KR100817891B1 - The Insulation Detecting Methods, Insulation Detecting System and Leakage current compensation devices for Electric Power Supply System - Google Patents

Abstract

The present invention relates to an insulation detection method, an insulation detection system, and a leakage current compensator for an electric wire path. More specifically, when the unbalanced capacitance is large, the reactive leakage current component becomes large, so that the effective leakage current component corresponding to the insulation condition of the wire cannot be accurately detected. The present invention relates to an insulation detection system and a leakage current compensator for detecting an insulation state of a three-phase line including a load by making it hardly detected and displaying only an effective leakage current component.

According to the present invention, the effective leakage current value due to the insulation resistance in the insulated state of the wire path can be detected with high sensitivity and the information of the worst phase can be known.

In addition, the leakage current compensator to offset the reactive leakage current flowing through the image transformer does not additionally generate the image leakage current between the cable line and the ground, so that it does not affect other insulation detectors and thus prevents malfunction of other insulation detectors. There is.

Insulation Detection, Leakage Current, Capacitance, Image Current, Leakage Current Compensator

Description

Insulation Detecting Methods, Insulation Detecting System and Leakage Current Compensation Devices for Electric Power Supply System

1 is a connection diagram illustrating a conventional leakage current detection method.

2 is a connection diagram of a conventional insulation detection system.

3 is a vector diagram illustrating a conventional insulation detection method.

Figure 4 is a connection diagram of a first embodiment of the insulation detection system of the present invention.

Figure 5 is a connection diagram of a second embodiment of the insulation detection system of the present invention.

Figure 6 is a connection diagram of a third embodiment of the insulation detection system of the present invention.

Figure 7 is a connection diagram of a fourth embodiment of the insulation detection system of the present invention.

8 is a connection diagram of Embodiment 5 of the insulation detection system of the present invention.

9 is a sixth embodiment connection diagram of the insulation detection system of the present invention.

Figure 10 is a connection diagram of a seventh embodiment of the insulation detection system of the present invention.

11 is a connection diagram of an eighth embodiment of the insulation detection system of the present invention.

12 is a connection diagram of Embodiment 9 of the insulation detection system of the present invention.

Figure 13 is a connection diagram of a tenth embodiment of an insulation detection system of the present invention.

14 is a detailed block diagram of the detector of the first embodiment of FIGS. 4 to 13;

FIG. 15 is a detailed block diagram of a second embodiment of the detector of FIGS. 4 to 13. FIG.

Fig. 16 is a detailed circuit diagram of a voltage component detecting means of the first embodiment of Fig. 14;

FIG. 17 is a detailed circuit diagram of a second embodiment of the voltage component detecting means of FIG. 15; FIG.

18 is a detailed circuit diagram of a first embodiment of the voltage conversion means of FIGS. 16 and 17;

FIG. 19 is a detailed circuit diagram of a second embodiment of the voltage converting means of FIGS. 16 and 17. FIG.

20 is a detailed circuit diagram of still another embodiment of the leakage current compensator of the present invention.

<Explanation of symbols for the main parts of the drawings>

10: video current transformer 12,13,14: voltage detection line

15: Leakage current compensation winding 20: Insulation detector

21: voltage component detecting means 22: leakage current detecting means

23: phase difference detecting means 24: leakage current display means

25: phase difference display means 30: leakage current compensator

31: compensation means 32: current phase selection means

33: ground direction selection means 211: voltage component conversion means

311: compensation capacitance part 312: compensation resistance part

The present invention relates to an insulation detection method, an insulation detection system, and a leakage current compensator for an electric wire path. More specifically, when the unbalanced capacitance is large, the reactive leakage current component becomes large, so that the effective leakage current component corresponding to the insulation condition of the wire cannot be accurately detected. The present invention relates to an insulation detection method for accurately detecting the insulation state of a three-phase line including a load, an insulation detection system, and a leakage current compensator for compensating an invalid leakage current so that almost no detection is made and only an effective leakage current component is displayed.

In particular, the present invention provides a method and system for detecting insulation of a three-phase wire path including a load, wherein the leakage current (Io) flowing between the wire path and the earth in an unbalanced state of capacitance existing between the wire path and the load including the load (Io). On the secondary side of the current transformer for detecting), the effective leakage current (Ir) due to the insulation resistance directly related to the insulation state and the reactive leakage current (Ic) due to the unbalance of the capacitance not directly related to the insulation state to the wire. Is represented by the vector sum (Io = Ir + Ic). Therefore, if the unbalanced state of the capacitance is large, the reactive leakage current component Ic becomes large, so that the effective leakage current component Ir corresponding to the insulation state of the wire path cannot be accurately detected and thus invalidated in the image current transformer. Insulation detection method, insulation detection system, and leakage current compensator that compensates for reactive leakage current accurately detect the insulation state of three-phase line including load by making minute leakage current hardly detected and showing only the effective leakage current component. It is about.

A conventional method of detecting an insulation state including a load on a wire line is to detect an image leakage current component flowing through the ground wire 5 in the grounded ground system on the secondary side of the transformer as shown in FIG. The method of detecting the image leakage current flowing between the grounds of () has been used. In the present invention, "wire line" means a power supply line including both a high-voltage distribution line and a low-voltage distribution line including a load. In addition, "image current transformer" means a current transformer capable of detecting a leakage current, the voltage detection line can be connected directly to the wire to detect the voltage component or by using a non-contact method to detect the voltage component to the wire Means that.

As shown in FIG. 1, a commercial AC voltage is supplied to a load 4 through a transformer 1, a switch 2, and an electric wire 3 for converting a voltage.

In FIG. 1, the secondary side of the transformer 1 is wired with a Y connection, and the neutral point of the wire connection is grounded to the ground 6 through the ground wire 5. Although it is not directly related to the effective leakage current (Ir) and the insulation state due to the insulation resistance (9) component directly related to the insulation state between the cable line (3) and the ground, the cable line (3) is long or the input terminal of the load (4) The reactive leakage current Ic flows due to the capacitance 8 component such as the noise filter present in the filter. An image leakage current Io = Ir + Ic, which is a vector sum of the two components, flows through the ground line 5 of the transformer.

The image leakage current (Io) is a leakage current detected as a leakage current detected at the secondary side of the current transformer 10 in which the middle of the ground line 6 of the transformer or the three phases of the wire line 3 are collectively passed. In general, a method of detecting an insulation state is widely used. Electrical apparatuses using the method of detecting the image leakage current (Io) as described above include a ground fault circuit breaker, a ground fault alarm, a ground fault detector, a ground fault detector, and a ground fault relay.

The conventional method of detecting only the image leakage current (Io) value shown in FIG. 1 is directly related to the insulation state when the unbalance between the three phases of the cable line 3 or the load 4 and the ground is large. Since the reactive leakage current Ic due to the electrostatic capacitance 8 component becomes large, the image leakage current Io is also detected as a bad insulation state even when the insulation resistance 9 is small, i.e., a good insulation state. Or even if the effective leakage current Ir caused by the constant insulation resistance 9 component flows according to the magnitude of the reactive leakage current Ic due to the capacitance 8 component, the image leakage current Io that is detected varies. There is a problem that accurate insulation detection is not possible.

As a method for solving this problem, the technique shown in Figs. 2 and 3 is disclosed in Japanese Utility Model Publication No. 58-180478.

In FIG. 2, the phase B of the transformer 1 is changed to detect an insulation state of the wire path 3 in a system in which power is supplied through the transformer 1, the switch 2, and the wire path 3 once grounded. An image current transformer 10 is installed in the middle of the ground wire 5 for connection to ground, and the image leakage current component (Io = Ir + Ic) detected in the secondary winding of the image current transformer 10 is connected to the wire. A separate capacitance compensation winding 11 or an electric wire for passing through the image current transformer 10 for compensating or removing the component of the reactive leakage current Ic due to the capacitance present between the earths of (3) and the capacitance One side of the compensating winding 11 is connected to each of the two non-grounded phase conductors, and the other side of the compensating winding 11 is connected to the grounded phase through several kinds of capacitors. Use (16). On the other hand, the vector sum current measuring device 18 connected to the secondary winding of the image transformer 10 measures the image leakage current (Io) flowing through the earth one by one in the power failure state, and the capacitor in the capacitance capacitor 16 Is adjusted to flow the reactive compensation current Ic 'in the opposite direction to the image leakage current Io component to the compensation winding 11 so as to minimize the vector sum as shown in the vector diagram shown in FIG. In this method, the load is measured in advance and records the value of the capacitance of the line 3 in the blackout state, and then the blackout in the image leakage current Io detected by the vector sum current meter 18 while the load is supplied with electricity. In this state, the reactive component leakage current component of the capacitance component measured and recorded is corrected and calculated, but the capacitance component existing at the load input terminal and the capacitance component generated by the load cannot be corrected or removed. In addition, in the wye connection where the side connection of the transformer 1 is not a delta connection, a capacitance component exists between all three phases and the capacitance component of each phase is unbalanced. Is 50mA and the reactive leakage current Ics due to the capacitance of S phase is 70mA, and the reactive leakage current Ict due to the capacitance of T phase is 100mA. Since the imbalance of the R phase and the S phase cannot be solved, the reactive current leakage component (Ic) caused by the capacitance flows through the image current transformer, so that there is a problem in that the leakage current component due to the accurate insulation resistance component cannot be detected.

In addition, since one capacitance is used for each phase, the ground wire of the transformer 1 or the ground wire of the transformer 1 can be used to detect the insulation state of the transformer 1 or immediately after the transformer 1, i.e., the entire transformer system. In the case of detecting the insulation state in the middle of the wire line 3 or near the load with the device for detecting the insulation state immediately after the transformer 1, the reactive compensation current Ic due to the capacitance to be corrected Ic. When the insulation detector is installed at the ground wire of the transformer 1 or immediately after the transformer 1, the reactive leakage current due to capacitance increases in the insulation detector, resulting in a comprehensive image leakage current (Io) component. There has been an increasing problem.

Therefore, in the three-phase cable path, when the side connection of the transformer 1 flows not only a delta connection but also a large amount of reactive leakage current Ic due to the unbalance of the ground-to-ground capacitance in the wye connection, Insulation detection method that can solve the problem that the effective leakage current (Ir) can not be detected and solve the problem of malfunction of other insulation detectors installed at the front end even in the middle of wire line 3 or near the load, and There has been a demand for an insulation detection system using the same, and a leakage current compensator capable of compensating for an invalid leakage current has been required.

SUMMARY OF THE INVENTION The present invention has been made to solve the problems of the prior art, and an object of the present invention is to provide an unbalanced state of capacitance existing between an electric line and a ground in a three-phase electric line, and to accurately connect the electric line even at a place close to the middle or load of the electric line. The present invention provides an insulation detection method capable of detecting an insulation state, an insulation detection system, and a leakage current compensator capable of compensating an effective leakage current or an effective leakage current by a capacitance component.

In order to achieve the object of the present invention, the voltage detection line for detecting the AC voltage of the three-phase wire; Voltage component detecting means for detecting a voltage component between the earths of each of the three phases inputted by the voltage detecting line; An image current transformer for detecting a leakage current component flowing between the three-phase wire path and the ground; Leakage current detection means for amplifying and filtering the leakage current component detected at the secondary side of the image current transformer; Phase difference detecting means for detecting a phase difference between the voltage component detected by the voltage component detecting means and the leakage current component output from the leakage current detecting means; Impedance of the three-phase alternating current between the three-phase AC voltage component inputted by the voltage detection line and the earth ground is made almost equal so that no additional leakage current flows in the actual cable line, and no leakage is caused by the capacitance of the actual cable line. In the insulation detection method for detecting the insulation state of the three-phase wire by providing a leakage current compensator for making a compensation leakage current capable of compensating the current to flow to the image current transformer or earth ground,

By using the leakage current value output from the leakage current detection means and the phase difference of each of the three phases detected by the phase difference detection means, the value of the reactive divided leakage current due to the capacitance detected at the secondary side of the image current transformer is Leakage current compensating current caused by the compensation capacitance by the capacitance operated by the leakage current compensator by the leakage current compensation winding formed by the test wire of the image current transformer or the primary winding configured separately so that the current flows through the image current transformer. In a state in which the current flows in the opposite direction or the same direction as the current, the leakage current component detected at the secondary side of the current transformer is detected to detect an insulation state of the wire.

According to still another aspect of the present invention, there is provided an insulation detection method comprising: a voltage detection line for detecting an AC voltage of a three-phase wire; Voltage component detecting means for detecting a voltage component between the earths of each of the three phases inputted by the voltage detecting line;

An image current transformer for detecting a leakage current component flowing between the three-phase wire path and the ground;

Leakage current detection means for amplifying and filtering the leakage current component detected at the secondary side of the image current transformer;

Phase difference detecting means for detecting a phase difference between the voltage component detected by the voltage component detecting means and the leakage current component output from the leakage current detecting means;

Impedance of the three-phase alternating current between the three-phase AC voltage component inputted by the voltage detection line and the earth ground is made almost equal so that no additional leakage current flows in the actual cable line, and no leakage is caused by the capacitance of the actual cable line. Insulation detection method for a wire path which detects the insulation state of a three-phase wire path by providing a leakage current compensator for making a compensatory leakage current for compensating an effective leakage current by current or insulation resistance and flowing it to the image current transformer or earth ground. To

By using the leakage current value output from the leakage current detection means and the phase difference of each of the three phases detected by the phase difference detection means, the leakage current value due to capacitance or insulation resistance detected at the secondary side of the current transformer is Leakage current compensation winding consisting of a test wire of a current transformer or a primary winding configured separately so that the leakage current for compensation caused by the capacitance or resistance manipulated by the leakage current compensator is opposite to the leakage current flowing through the image current transformer. Or flowing in the same direction; And detecting the insulation state of the cable line by using the compensation leakage current value flowing by the capacitance or the resistance operated by the leakage current compensator.

In addition, the insulation detection system of the present invention includes an image current transformer for detecting a leakage current component flowing between the three-phase cable line and the ground; Leakage current detection means for amplifying and filtering the leakage current component detected by the image current transformer; Leakage current display means for displaying an output value of the leakage current detection means; Voltage component detecting means for detecting a voltage component between the cable line and the ground, converting the voltage component into a predetermined magnitude, and selecting the voltage component of one of the three phases; Phase difference detecting means for detecting a phase difference between the voltage component detected by the voltage component detecting means and the leakage current component output from the leakage current detecting means; Phase difference display means for displaying an output value of the phase difference detection means; Impedance of the three-phase AC voltage component inputted by the voltage detection line and the three-phase each phase between the earth ground is made almost the same so that no additional leakage current flows in the actual line and the leakage current due to the capacitance of the actual line And a leakage current compensator for making a compensatory leakage current for compensation and flowing it to the image current transformer or ground.

In addition, another insulation detection system of the present invention includes an image current transformer for detecting a leakage current component flowing between the three-phase wire and the ground; Leakage current detection means for amplifying and filtering the leakage current component detected by the image current transformer; Leakage current display means for displaying an output value of the leakage current detection means; A voltage detection line for detecting an AC voltage of the three-phase wire;

Converts the voltage component between the three phases of each phase input by the voltage detection line to a certain magnitude and selects the voltage component of one of the three phases or detects the voltage components of all three phases of each phase input by the voltage detection line. Voltage component detecting means for performing;

Phase difference detecting means for detecting a phase difference between the voltage component detected by the voltage component detecting means and the leakage current component output from the leakage current detecting means;

Phase difference display means for displaying an output value of the phase difference detection means;

The three-phase AC voltage component inputted by the voltage detecting line and the grounding of the three-phase each phase are configured to be substantially the same, so that no additional leakage current flows in the actual line, and the capacitance and insulation resistance of the actual line It characterized in that it comprises a leakage current compensator for making a leakage current for compensation to compensate for the leakage current and flowing to the image current transformer or ground.

The voltage component detecting means includes: voltage component converting means for detecting a voltage component between an electric line and a ground and converting the voltage component into a predetermined magnitude; And voltage phase selection means for reading the voltage of one phase of the three phase voltage components converted by the voltage component converting means.

Leakage current compensator of the present invention for achieving the object of the present invention and the voltage detection line for detecting the commercial AC voltage of the three-phase wire; Compensating means for constructing a three-phase commercial AC voltage component detected by the voltage component detecting means and an impedance of each of the three phases between the earth ground and making a compensatory leakage current; Leakage current compensation winding means for flowing a compensatory leakage current through the image current transformer to earth ground; Current phase selection for selecting whether to flow the compensatory leakage current flowing through the compensating means to the earth ground for each of the three phases or through the leak current compensation winding means by the commercial AC voltage of the voltage component detecting means. Way; The direction of the compensating leakage current flowing through the current phase selection means is configured to be in the opposite direction or the same direction as the direction of the leakage current flowing between the wire and the ground including the actual load.

Another leakage current compensator of the present invention for achieving the object of the present invention includes a voltage detection line for detecting a commercial AC voltage in the three-phase wire; Compensating means for constructing a three-phase commercial AC voltage component detected by the voltage component detecting means and an impedance of each of the three phases between the earth ground and making a compensatory leakage current; Leakage current compensation winding means for flowing a compensatory leakage current through the image current transformer to earth ground; Current phase selection for selecting whether to flow the compensatory leakage current flowing through the compensating means to the earth ground for each of the three phases or through the leak current compensation winding means by the commercial AC voltage of the voltage component detecting means. Way; And a ground direction selection means for selecting whether to flow the leakage current for compensation flowing through the current phase selection means in the same direction as the direction of the leakage current flowing between the cable line and the earth including the actual load or in the opposite direction. It is characterized in that the configuration.

The compensating means includes: a compensating capacitive section comprising at least one capacitance for compensating the reactive leakage current by the capacitance for each phase; Characterized in that it comprises a compensation resistor portion consisting of one or more resistors for compensating the effective leakage current by the insulation resistance.

The current phase selection means includes an invalid portion direction selection section for selecting whether to flow an invalid portion compensation current to the ground side or a leakage current compensation winding side; And an effective portion direction selection section for selecting whether the effective portion compensation current flows to the ground side or the leakage current compensation winding side.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

1 is a connection diagram illustrating a conventional leakage current detection method, FIG. 2 is a connection diagram of a conventional insulation detection system, and FIG. 3 is a vector diagram illustrating a conventional insulation detection method.

Figure 4 is a wiring diagram of a first embodiment of the insulation detection system of the present invention, Figure 5 is a wiring diagram of a second embodiment of the insulation detection system of the present invention, Figure 6 is a connection diagram of a third embodiment of the insulation detection system of the present invention. .

Figure 7 is a connection diagram of the fourth embodiment of the insulation detection system of the present invention, Figure 8 is a connection diagram of the fifth embodiment of the insulation detection system of the present invention, Figure 9 is a connection diagram of the sixth embodiment of the insulation detection system of the present invention. .

10 is a connection diagram of a seventh embodiment of the insulation detection system of the present invention, FIG. 11 is a connection diagram of an eighth embodiment of the insulation detection system of the present invention, and FIG. 12 is a connection diagram of a ninth embodiment of the insulation detection system of the present invention. 13 is a connection diagram of Embodiment 10 of the insulation detection system of the present invention.

14 is a detailed block diagram of the first embodiment of the detector of FIGS. 4 to 13, and FIG. 15 is a detailed block diagram of the second embodiment of the detector of FIGS. FIG. 16 is a detailed circuit diagram of the voltage component detecting means of the first embodiment of FIG. 14, and FIG. 17 is a detailed circuit diagram of the second embodiment of the voltage component detecting means of FIG. FIG. 18 is a detailed circuit diagram of the voltage conversion means of the first embodiment of FIGS. 16 and 17, and FIG. 19 is a detailed circuit diagram of the second embodiment of the voltage conversion means of FIGS. 20 is a detailed circuit diagram of still another embodiment of the leakage current compensator of the present invention.

Figure 4 is a connection diagram of a first embodiment of the insulation detection system of the present invention. Fig. 5 is a connection diagram of a second embodiment of the insulation detection system of the present invention.

4 and 5 are different from those connected from the current phase selecting means 32 in the leakage current compensator 30 to the leakage current compensating winding 15. In FIG. 4, the current transformer in the current phase selecting means 32 is different. While the leakage current compensation winding 15 is connected to ground from the load 4 side of the primary side to the transformer 1 side, the image current transformer 10 is connected to the current phase selection means 32 in FIG. The leakage current compensation winding 15 is connected from the transformer 1 side of the primary side to the load 4 side and connected to ground.

4 is to reverse the flow direction of the image leakage current Io flowing between the actual cable 3 and the ground, and the compensation of the reactive compensation current Ic 'flowing by the compensation means 31 is shown in FIG. The reactive compensation current Ic 'flowing through the melting means 31 is characterized in that it is made the same direction as the flow direction of the image leakage current Io flowing between the actual cable line 3 and the ground.

 Figure 6 is a connection diagram of a third embodiment of the insulation detection system of the present invention. 7 is a connection diagram of a fourth embodiment of the insulation detection system of the present invention.

Fig. 6 shows that only the one side of the reactive compensation current Ic 'of Figs. 4 and 5 can be selected by the ground direction selecting means 33 to change the direction of the reactive compensation current Ic' to the electric wire 3. ) May be selected in the flow direction of the image leakage current Io flowing between the ground and the ground, or in the opposite direction to the flow direction of the image leakage current Io.

7 is a connection diagram of a fourth embodiment of the insulation detection system of the present invention. FIG. 7 illustrates that the secondary connection of the transformer 1 in FIGS. 4 to 6 can be used in the delta connection.

FIG. 8 illustrates that the compensating means 31 in the leakage current compensator 30 in FIGS. 4 to 7 may be connected to the ground side of the leakage current compensation winding 15. will be.

Differences between FIG. 14 and FIG. 15, which are detailed block diagrams of the insulation detector 20, will be described in detail below. In FIG. 14, the voltage component detection means 21 detects voltage components one by one and detects the leakage current in the phase detection means 23. Although the phase difference with the image leakage current (Io) component output from the means 22 is detected one phase, in FIG. 15, the voltage component detecting means 21 detects the voltage component in all three phases, and thus the phase detecting means 23 is detected. The phase difference with the image leakage current (Io) component outputted from the leakage current detecting means 22 is different from that of detecting one phase or three phases at once.

The difference between FIG. 16 and FIG. 17 is that the voltage component detecting means 21 in the insulation detector 20 of FIG. 14 uses the voltage phase selecting means 212 to detect the voltage components one by one. FIG. 18 corresponds to the voltage component detecting means 21 in the insulation detector 20 of FIG. 15, except that the voltage phase selecting means 212 is not used to simultaneously detect the three-phase voltage component.

18 and 19 show the configuration of the voltage component converting means 211 in the voltage component detecting means 21 of FIGS. 16 and 17, such as whether to use a resistor, a capacitor, or a transformer (TR). It is for describing various embodiments.

(First embodiment)

4, 14, and 16 will be described first as a first embodiment for explaining the insulation detection method, insulation detection system, and leakage current compensator of the present invention.

In FIG. 4, the transformer 1 supplies electric power to the wire path 3 through the switch 2 as a transformer for converting voltage. Reference numeral 5 is a ground wire for connecting the neutral point of the transformer 1 to the ground 6 for safety. When insulation deterioration occurs between the cable line 3 including the load 4 and the earth while power is supplied to the load 4 through the switch 2 and the wire line 3, the insulation resistance 8 is insulated. The resistance value is lowered, and the effective leakage current Ir caused by the insulation resistance flows through the insulation resistance 9 to the ground. If only the effective leakage current Ir by the insulation resistance can be detected, the earth-to-earth insulation state of the cable line 3 can be known.

However, in the case where the cable line 3 is a long-distance line, or in the case of the cable line 3 divided into several places, the capacitance C becomes large due to the parallel synthesis of the cable-to-earth capacitance of the cable line 3. In particular, in the case where the load 4 is an electronic precision equipment, an electronic component such as a noise filter is often inserted between the input terminal and the ground to prevent noise from entering the input terminal of the load 4. Since electronic components such as noise filters have many capacitor components, a large amount of reactive leakage current (Ic) flows due to the capacitance that is 90 degrees ahead of the voltage which is not directly related to the insulation state, and the load 4 is the same as that of inverters. In the power electronic equipment which controls the equipment by using the power electronic device, the reactive leakage current (Ic) due to the capacitance flows to the ground through the capacitor included in the equipment by the high frequency when controlling the frequency or the voltage at high frequency. Or a high frequency generated in a facility such as an inverter flows through the capacitance between the cable and the ground, and the reactive leakage current (Ic) flows due to the capacitance larger than the commercial frequency, and the cable line 3 is long. Since the capacitance is synthesized in parallel between the cable line 3 and the ground, the longer the length of the cable line 3 is, the larger the thickness of the cable of the cable line 3 is, the larger the capacitance becomes. The larger the void leakage current (Ic) according to the capacity. When the reactive leakage current Ic caused by the above-mentioned capacitance flows in the same magnitude between the three-phase RST phase and the ground, the three phases are balanced, and the three-phase vector sum of the reactive leakage currents Ic due to capacitance is almost zero ( In a complex system where single-phase loads are used in three-phase lines or branched into multiple loads, the capacitance between three phases is difficult to balance. This unbalanced capacitance increases the reactive leakage current Ic due to the capacitance flowing between the cable line 3 and the ground.

In addition, the effective leakage current (Ir) due to the insulation resistance and the reactive leakage current (Ic) due to the capacitance flow together between the line 3 and the ground, and as described above, the earth of the line 3 To detect the image leakage current flowing to the ground to know the insulation state between the terminals, an image current transformer 10 such as ZCT is connected to the middle of the wire line 3 or the neutral point of the transformer 1 or the ground on one end of the transformer 1. Install in the middle of connected ground wire (5). Since the image current transformer 10 is represented by the vector sum of the effective divided leakage current Ir due to the insulation resistance and the reactive divided leakage current Il due to the capacitance, the insulation current is very large, that is, even if the insulation state is satisfactory. Image leakage current, which is a vector sum of Ir and Ic detected in the secondary winding of the image transformer 10, as the reactive leakage current Ic caused by the capacitance flowing to the ground due to the unbalance of the capacitance not directly related to the state increases. (Io) is largely detected.

Since the effective leakage current Ir due to the insulation resistance cannot be separated only by the magnitude of the image leakage current Io, which is the vector sum of Ir and Ic, the phase difference θ with the commercial AC voltage component of the cable line 3 is determined. The cosθ of the image leakage current Io, which is in phase with the voltage component, is the effective leakage current Ir due to the insulation resistance, and the sinθ of the image leakage current Io, which is 90 degrees out of phase with the voltage component, The method of separating the reactive leakage current (Ic) by means of a single phase is effective in single phase, but in three phases, since each of the three phases has a 120-degree phase difference, the three-phase composite image leakage current (Io) is equal to the phase component of each of the three phases. Since the phase-phase components are mixed, it is very difficult to separate the effective leakage current Ir and the reactive leakage current Ic.

Also, the larger the effective leakage current Ic in the state where the constant effective leakage current Ir flows, the more accurate the effective leakage current Ir is caused by the magnetic field characteristic of the image current transformer 10 on the secondary side of the image transformer 10. It is very difficult to accurately detect the magnitude of the effective leakage current (Ir) due to the phenomenon that the magnitude does not appear.

Therefore, in order to detect and detect the insulation state of the cable line 3, in order to accurately detect the earth-to-earth insulation state of the cable line 3 including the load 4 with high sensitivity even in the unbalanced state of capacitance, the image leakage current flowing between the earths The reactive current leakage current Ic caused by the capacitance flows very small in the image current transformer 10 such as ZCT that detects the component of Io, and the image current transformer 10 has an effective leakage current Ir due to insulation resistance. Since only the component is required to flow, the reactive current leakage current Ic ', such as the reactive leakage current Ic, caused by the capacitance flowing in the primary winding of the image current transformer 10 in the opposite direction, flows in the opposite direction. It is necessary to minimize the leakage current component Ic due to the capacitance detected in the secondary winding of 10) and to prevent unnecessary additional leakage current components from appearing between the line 3 and the ground.

As described above, an image current transformer 10 such as ZCT for detecting a component of the image leakage current Io is provided in the middle of the wire line 3 or the ground line 5 of the transformer 1, and the phase difference? Voltage detection lines (12, 13, 14) for detecting the voltage components of each phase of the wire line (3) necessary for detecting the phase difference, and the phase difference of each phase of each of the three phases and the component size of the image leakage current (Io) The secondary side of the image current transformer 10 and the voltage detection lines 12, 13, and 14 are connected to an insulation detector 20 for detecting (θ). The insulation detector 20 is shown in detail in FIG. Then, the capacitance is manipulated from the phase where the reactive leakage current caused by the capacitance among the three phases flows the most by the phase difference θ for each of the three phases and the image leakage current Io detected by the insulation detector 20. The leakage current compensator 30 and the leakage current compensator to prevent the reactive leakage current Ic from being detected by the secondary winding of the The leakage current for causing the reactive compensation current Ic 'due to the capacitance operated in 30) to flow in a direction opposite to the flow of the leakage current passed through the three-phase package (or the ground line of the transformer) of the image transformer 10. The compensation winding means 15 uses a test line of the image current transformer in the image current transformer 10 or uses a separate auxiliary winding. The leakage current compensator 30 includes compensation means 31 for generating various reactive compensation currents Ic 'and an invalid compensation current Ic' flowing through the capacitance of the compensation means 31. Is provided for each phase to select whether to flow to the ground side or to the leakage current compensation winding 15 side. When the current phase selection means 32 do not operate, the current flowing through the capacitance of the compensating means 31 flows to the ground side, and the values of the capacitances C1, C2, and C3 are different. However, the combined capacitance (C1 + C2 + C3) values for each of the three phases may be configured to be substantially the same so that the ground or the leakage through the voltage detecting lines 12, 13, and 14 and the compensating means 31 are achieved. Preferably, the reactive leakage current flowing through the current compensation winding 15 to ground is balanced.

For example, the voltage between the three-phase line (3) and the ground is 220 V 60 Hz, and the effective part leakage current flowing through the insulation resistance (9) between each phase and the ground is: R phase is Irr = 1 mA, S phase is Irs = 40 mA, T As an example, a phase-discharge leakage current flowing through the capacitance 8 between each of the three phases and the ground, that is, the phase is Irt = 1 mA, that is, the R phase is Icr = 60 mA, the S phase is Ics = 20 mA, and the T phase is Ict = 20 mA. Actually, the vector sum of the effective leakage current flowing through the insulation resistance 9 is 39 mA, and the vector sum of the reactive leakage current flowing through the capacitance is 40 mA. However, the leakage current flowing between the cable line and the ground, i.e., the leakage current flowing through the image current transformer is about 76mA, and detecting only 76mA did not accurately determine the effective leakage current due to the insulation resistance flowing between the cable line and the ground. The present invention is to implement a method and a device that can accurately detect the effective leakage current Ir = 39mA, and Ic = 40mA generated due to the large amount of reactive leakage current caused by the capacitance of R phase compared to other phases. The voltage component of the R phase in the direction opposite to the current flow of the image leakage current flowing between the actual line 3 and the earth as the primary winding of the image transformer so that the value detected at the secondary side of the image transformer 10 becomes almost zero. In the state where the reactive compensation current Ic '= 40mA having a phase difference of 90 degrees flows, the image compensation current Io', which is detected on the secondary side of the image transformer 10, that is, almost no component of the reactive leakage current Ic is hardly detected. Instead, only the effective leakage current due to the insulation resistance is to be detected.

When the image leakage current Io detected by the secondary side of the image transformer 10 is inputted to the insulation detector 20 as shown in FIG. 8, the leakage current display means amplifies and filters the leakage current and displays the leakage current. The leakage current component (Io) displayed by the means (25) and amplified and filtered by the leakage flow detection means (22) is outputted to the phase detection means (23). In FIG. 16, when the voltage component of the three-phase each phase between the grounds of the wire line 3 input by the voltage detection lines 12, 13, and 14 is input to the insulation detector 20 as shown in FIG. In the example voltage component detecting means 21, the resistances Rv1 and Rv2 of the voltage component converting means 211 are converted as shown in Equation 1 below.

 That is, the voltage component of each phase of three phases is converted at the same ratio as in Equation 1, and there is no phase change, and the value of each phase of Rv1 in order to eliminate leakage current caused by the unbalance of the resistors Rv1 and Rv2 in addition to the actual line. Is the same and it is preferable to make the value of Rv2 the same. The voltage component of each of the three-phase phases converted by the voltage component converting means 211 is a voltage component of the R phase when the switch sw_v of the voltage phase selecting means 212 is selected to the r side, and the switch sw_v is moved to the s side. If it is selected, the voltage component of the S phase is output to the phase detecting means 23 when the switch sw_v is selected to the t side. The image leakage current component Io output from the leakage current detecting means 22 and the image leakage current component Io for the voltage component of the phase selected by the voltage phase selection means 212 and the voltage component of each of the three phases. The phase difference is detected and displayed on the phase difference display means 24.

The image leakage current component (Io) displayed on the leakage current display means 25 can be expressed as in Equation 2 below.

Where V and I are vector functions.

For example, the phase difference of the image leakage current Io with respect to the R phase voltage component displayed by the phase difference display means 24 is θr, and the phase difference of the image leakage current Io with respect to the S phase voltage component is θs, T phase. If the phase difference of the image leakage current (Io) with respect to the voltage component is θ t

The component of the image leakage current Io with respect to the R phase voltage component may be expressed as shown in Equation 3,

The component of the image leakage current Io with respect to the S phase voltage component may be expressed as shown in Equation 4,

The component of the image leakage current Io with respect to the T phase voltage component may be expressed as shown in Equation 5.

For example, as described above, the effective leakage current Irr = 1 mA due to the resistance component flowing in R phase, the reactive leakage current Icr = 60 mA due to capacitance, and the effective leakage current Irs due to the resistance component in S phase. In a three-phase wire line where = 1 mA, the reactive leakage current Ics = 20 mA due to capacitance, the effective leakage current Irt = 1 mA due to the resistance component flowing in T phase, and the reactive leakage current Ict = 20 mA due to capacitance, The value of the image leakage current detected and displayed by the leakage current detection means 22 and the leakage current display means 25 connected to the secondary side of the image current transformer 10 is Io = 76.3mA, and the voltage detection line 12, 13 and 14 and a phase difference between the image leakage current component outputted from the leakage current detecting means 22 for the voltage component of each of the three phases detected through the voltage component detecting means 22; 23) and each of the three-phase each phase detected and displayed by the phase difference display means 24 The phase difference with respect to the voltage component, that is, the phase difference with the image leakage current (Io) with respect to the voltage component of the R phase is θ r = 104.8, the phase difference with the image leakage current (Io) with respect to the voltage component of the S phase is θ s = -15.2, and the voltage of the T phase The phase difference with the image leakage current Io for the component is θ t = -135.2.

Substituting the equations 3 to 5 for each of the three phase phases using the values of Io, θr, θs, θt, Io for the voltage component of R phase is -19.5 + j73.8, and Io for the voltage component of S phase is 73.6. Io for the voltage component of -j20.0, T phase can be calculated as -54.1-j53.8. In addition, the left term of the value of Io is in phase with respect to the voltage, and the right term, i.e., the term j contains 90 degrees with respect to the voltage.

Next, a check is made to see if any of the three phases has a large amount of reactive leakage current Ic due to capacitance. First, confirming that each of the in-phase and 90-degree phases of the leakage current with respect to the voltage of each phase is larger, the 90-phase phase of the R phase is the largest and the in-phase of the S phase is the largest. It is common that the 90-degree phase of R phase becomes + (plus) when the reactive leakage current (Icr) of R phase is large or the effective leakage current (Irs) of S phase is large. In phase, the phase in phase becomes + (plus) when the effective phase leakage current (Irs) of S phase is large or the reactive leakage current (Icr) of R phase is large. In order to reconfirm that the Icr and Irs values identified above are the largest, confirm that the in phase and the 90 degree phases of the leakage current with respect to the voltage of each phase are respectively small, the phase phase of the T phase is the smallest and the 90 degree phase of the T phase is smaller. You can see that it is the smallest. As shown in Equation 5, the in phase of T phase becomes-(minus), the effective leakage current (Irr) of R phase is large, or the effective leakage current (Irs) of S phase is large, or the reactive leakage current of R phase ( It is common for Icr) to be large, and the 90-phase phase of T phase becomes-(minus), as shown in Equation 5, the reactive leakage current (Icr) of R phase is large or the reactive leakage current of S phase of S phase. Since (Ics) is large or the effective leakage current (Irs) of the S phase is large, it is invalid for the R phase to satisfy the combination of the effective and reactive leakage currents of each phase with respect to the largest and smallest values. It is understood that the divided leakage current Icr is large and the effective divided leakage current Irs of the S phase is large.

Next, when the reactive leakage current of a certain magnitude flows in the opposite direction to the leakage current flowing in the actual line to the primary side of the image transformer 10, the primary side of the image transformer 10 has the largest reactive phase leakage current. By canceling the reactive leakage current flowing in the flow to the secondary side of the current transformer 10 to calculate whether the reactive leakage current is not detected. The j term of Equation 3 to Equation 5, i.e., calculates the value of Icr 'that becomes 90 degrees phase is zero.

Expression 3 Equation 4 Equation 5 Icr 'calculation About-73.8 -40.0 About -107.6 Image leakage current calculation value for R phase voltage -19.5 + j0.0 -19.5 + j33.8 -19.5-j33.8 Image leakage current calculation for S phase voltage 9.8 + j16.9 39.0 + j0.0 -19.5 + j33.8 Image leakage current calculation value for T phase voltage 9.8-j16.9 -19.5-j33.8 39.0 + j0.0

In Table 1, since the effective leakage current Irs of the S phase corresponds to Equation 4, the reactive compensation current Icr 'for the R phase is 40 mA.

Next, C1, C2, and C3 of the compensation means 31 connected to the R phase, that is, the voltage detection line 12 in the leakage current compensator 30 (in the embodiment of the present invention, each capacitor consists of three capacitor elements, The phase voltage between the wire path 3 and the ground is calculated so that the reactive compensation current Icr 'of the contact switches sw1r, sw2r, and sw3r of the current phase selection means 32 is 40 mA. Switching the contact switch corresponding to the leakage current compensation winding 15 side, the corresponding capacitance (C1, C2, C3) and the current phase selection means of the voltage detection line 12 and the compensation means 31 (32) and the leakage current compensation winding (15) to the primary side of the current transformer 10, the direction of the image leakage current (Io) flowing between the actual cable line 3 and the ground, that is, of the current transformer 10 From the load side, it passes through the image transformer 10 and flows to the ground side, and the reactive leakage current Ic is canceled, so that 2 of the image transformer 10 Valid only leakage current (Ir) component by little insulation resistance (9) side is detected.

Next, in the state where the reactive compensation current Ic 'of the R phase, that is, the reactive compensation current Icr' in the R phase, flows through the leakage current compensation winding 15 to the primary winding of the image transformer 10. The leakage current detection means 22 in the insulation detector 20 to which the secondary side of the image current transformer 10 is connected detects the image correction current Io ′ through amplification and filtering processes, and detects the leakage current detection means ( The image compensating current Io 'detected at 22 is displayed on the leakage current display means 25, and the voltage component detecting means in the insulation detector 20 to which the voltage detection lines 12, 13 and 14 are connected ( 21 converts the phase voltage of each of the three phase phases into a constant voltage in the voltage component conversion means 211, and converts the phase voltage of each of the three phase phases converted from the voltage component conversion means 211 into the voltage phase selection means 212. Switch the sw_v switch to r side in 3 phase sequence to detect the voltage component of R phase. R phase voltage component detected by the voltage phase selecting means 212 and the image correction current Io 'detected by the leakage current detecting means 22 are inputted to the R phase voltage component. The phase difference [theta] r 'of the image correction current Io' is detected, and the phase difference [theta] r 'detected by the phase detection means 23 is displayed. Next, the sw_v switch in the voltage phase selecting means 212 is switched to the s side to detect the voltage component for the S phase, and the voltage component of the S phase detected by the voltage phase selecting means 212 and the leakage current detecting means ( Phase detection means 23 to which the image correction current Io 'detected in 22) is inputted detects the phase difference θs' of the image correction current Io' with respect to the S-phase voltage component, and the phase detection means 23 Indicates the phase difference θs' detected in S phase. Next, the sw_v switch in the voltage phase selecting means 212 is switched to the t side to detect the voltage component for the T phase, and the voltage component of the T phase detected by the voltage phase selecting means 212 and the leakage current detecting means ( The phase detection means 23 to which the image correction current Io 'detected in 22) is inputted detects the phase difference θt' of the image correction current Io 'with respect to the T phase voltage component, and the phase detection means 23 Indicates the phase difference θt 'detected in S phase.

When reconfirming that the phase difference θs 'with the image correction current Io' for the S phase voltage component is almost zero, or the phase difference θr 'with the image correction current Io' for the other R and T phase voltage components, When? t 'is determined to be 120 degrees or -120 degrees, the image correction current Io' detected above is applied to the effective leakage current Ir flowing by the insulation resistance 9 flowing between the actual cable line 3 and the earth. The reactive current leakage current (Ic) almost does not flow to the primary side of the current transformer 10, so that the image current transformer 10 is equal to 2 of the current transformer 10 by a small amount of the effective current leakage current Ir. Since it is induced on the vehicle side, the effective resistance leakage current Ir flowing to the ground can be detected by the insulation resistance 9 which is directly related to the earth leakage with high sensitivity, and the phase in which the insulation is the worst, that is, the earth leakage can be identified. Intensive for awards that are being shorted As a result, it is possible to save time by investigating and evaluating the leakage current, and additionally, the information of the phase with the largest capacitance and the amount of the reactive leakage current (Ic) are also known. It becomes possible. On the other hand, if the θs' with the image correction current Io 'for the S phase voltage component is not substantially zero, the reactive compensation current Icr' for the R phase is passed to the leakage current compensating means 15. It is preferable to detect and display the effective leakage current Ir in a state where the reactive leakage current Ic component is hardly detected on the secondary side of the image transformer 10 by repeatedly performing the above-described operation in the Do.

In the example described above, when the reactive leakage current Ic due to the capacitance of one of the three phases flows large, the detection of the invalid residual compensation current Ic 'is performed for the phase where the reactive leakage current Ic is large. The current flows in the direction opposite to the current flow direction of the image leakage current Io flowing between the cable line 3 and the ground. However, if the reactive leakage current Ic is large due to the capacitance of two phases out of three phases, it is invalid. The two phases having the large divided leakage current Ic are simultaneously detected and calculated in the opposite direction to the current flow direction of the image leakage current Io flowing between the actual cable line 3 and the ground. It is recommended to use a method of checking whether the image correction current (Io) is almost zero by flowing the correction current for the largest phase or the current for the next smallest phase. Is recommended.

(Second embodiment)

Next, FIGS. 5, 15, and 17 will be described as a second embodiment for explaining the insulation detection method, insulation detection system, and leakage current compensator of the present invention.

The configuration of FIG. 5 is substantially the same as that of FIG. 4 described above, but in FIG. 4, which is the first embodiment, voltage detection lines 12, 13, and 14 connected to detect voltage components of the three-phase respective phases between the cable line 3 and the earth. ) Is connected to the leakage current compensator 30 and is connected to the ground side of the current phase selection means 32 through the capacitances C1, C2, C3 in the compensating means 31. The other contact of the current phase selection means 32 is connected to the leakage current compensation winding 15 connected to the ground through the primary side of the image transformer 10 from the load 4 of the image transformer 10 to the transformer 1 side. While the current flow direction of the reactive compensation current c 'is configured to be opposite to the flow direction of the image leakage current Io between the wire path 3 and the ground, the wire path in FIG. Voltage detection lines 12, 13 and 14 connected to detect voltage components of the three-phase respective phases between the ground and the ground (3) are connected to the leakage current compensator 30 so that the capacitances C1 and C2 in the compensation means 31 can be obtained. C3 is connected to the ground side of the current phase selection means 32. The other contact point of the current phase selecting means 32 is a leakage current compensation winding 15 connected to ground through the primary side of the image transformer 10 from the transformer 1 of the image transformer 10 to the load 4 side. The current flow direction of the reactive compensation current (c ') is connected in the same direction as the flow direction of the image leakage current (Io) between the cable line 3 and the ground.

As described in the first embodiment, in detecting the insulation state of the cable line 3, the earth-to-earth insulation state of the cable line 3 including the load 4 can be detected with high sensitivity even in the unbalanced state of the capacitance. To this end, the reactive current leakage current Ic due to capacitance flows very small to the image current transformer 10 such as ZCT which detects the component of the image leakage current Io flowing between the grounds, and the insulation resistance of the image current transformer 10 is reduced. Only the effective component leakage current Ir is required to flow. In the first embodiment described above, the reactive current correction current Ic 'is applied to the image current transformer 10 for the phase where the reactive component leakage current Ic is the largest. Leakage current component due to capacitance detected on the secondary side of the image transformer 10 by flowing an invalid portion correcting current Ic 'such as an invalid portion leakage current Ic due to capacitance flowing on the primary side of (Ic) almost appears In the second embodiment of the present invention, the static electricity flowing in the reactive current correction current Ic 'to the primary side of the image transformer 10 is applied to two phases other than the phase where the reactive leakage current Ic has the largest value. The reactive current correction current Ic 'such as the reactive current leakage current Ic caused by the capacitance flows in the same direction so that the leakage current component Ic due to the capacitance detected on the secondary side of the image transformer 10 hardly appears. It is.

As described above, an image current transformer 10 such as ZCT for detecting a component of the image leakage current Io is provided in the middle of the wire line 3 or the ground line 5 of the transformer 1, and the phase difference? Voltage detection lines (12, 13, 14) for detecting the voltage components of each phase of the wire line (3) necessary for detecting the phase difference, and the phase difference of each phase of each of the three phases and the component size of the image leakage current (Io) The secondary side of the image current transformer 10 and the voltage detection lines 12, 13, and 14 are connected to an insulation detector 20 for detecting (θ). The insulation detector 20 is shown in detail in FIG. 15. In addition, the phase leakage current Io detected by the insulation detector 20 and the phase capacitance of each of the three phases are determined by the phase difference θ. The leakage current compensator 30 and the leakage current compensator for operating the three-phase electrostatic capacitance so that the reactive leakage current Ic due to the capacitance are not detected on the secondary side of the current transformer 10 are operated. The leakage current for causing the reactive compensation current Ic 'caused by the capacitance operated in 30) to flow in the same direction as the flow of leakage current passed through the three-phase package (or the ground line of the transformer) of the image transformer 10. The compensation winding means 15 uses a test line of the image current transformer in the image current transformer 10 or uses a separate auxiliary winding. The leakage current compensator 30 includes compensation means 31 for generating various reactive compensation currents Ic 'and an invalid compensation current Ic' flowing through the capacitance of the compensation means 31. Is provided for each phase to select whether to flow to the ground side or to the leakage current compensation winding 15 side. When the current phase selection means 32 do not operate, the current flowing through the compensation means 31 flows to the ground side, and the values of the capacitances C1, C2, and C3 may be different. The combined capacitance (C1 + C2 + C3) values for each of the three phases are configured to be substantially the same so that the ground or the leakage current compensation windings are connected through the voltage detection lines 12, 13, and 14 and the compensation means 31. It is preferable that the reactive leakage current flowing to ground through (15) be balanced. An example is demonstrated.

The voltage between the three-phase cable line (3) and the ground is 220V 60 Hz, and the effective leakage current flowing through the insulation resistance (9) between each phase and the ground is: R phase is Irr = 1 mA, S phase is Irs = 40 mA, and T phase is Irt = 1 mA. For example, an inductor leakage current flowing in the capacitance 8 between each of the three phases and the ground, i.e., an Icr = 60mA for the R phase, an Ics = 20mA for the S phase, and an Ict = 20mA for the T phase, for example,

The vector sum of the effective leakage current flowing through the actual insulation resistance 9 is 39 mA, and the vector sum of the reactive leakage current flowing through the capacitance is 40 mA. However, the leakage current flowing between the cable line and the ground, i.e., the leakage current flowing through the image current transformer is about 76mA, and detecting only 76mA did not accurately determine the effective leakage current due to the insulation resistance flowing between the cable line and the ground. The present invention is to implement a method and a device that can accurately detect the effective leakage current Ir = 39mA, and Ic = 40mA generated due to the large amount of reactive leakage current caused by the capacitance of R phase compared to other phases. S-phase and T-phase in the same direction as the current flow of the image leakage current flowing between the actual cable line 3 and the earth with the primary winding of the image transformer so that the value detected at the secondary side of the image transformer 10 becomes almost zero. Image compensating current Io 'detected at the secondary side of the image transformer 10 in the state where an invalid component compensating current Ic' = 40mA having a 90-degree phase difference from the voltage component is respectively applied, that is, an almost reactive component leakage current Ic component. This is hardly detected and only the effective leakage current due to the insulation resistance is to be detected.

That is, when the image leakage current Io detected by the secondary side of the image current transformer 10 is input to the insulation detector 20 as shown in FIG. 15, the leakage current detection means 22 undergoes amplification and filtering to prevent leakage. The current leakage means (Io) is displayed on the current display means (25), and the leakage current component (Io) amplified and filtered by the leakage flow detection means (22) is output to the phase detection means (23). When the voltage component of the three-phase each phase between the ground of the cable line 3 input by the voltage detection lines 12, 13, 14 is input to the insulation detector 20 as shown in FIG. In the example voltage component detecting means 21, the resistances Rv1 and Rv2 of the voltage component converting means 211 are converted as shown in Equation 1 above.

In FIG. 16, which is a detailed circuit diagram of the voltage component detecting means in the first embodiment described above, the voltage components of each of the three phases are sequentially detected one by one by sw_v of the voltage phase selecting means 212. FIG. On the other hand, in FIG. 17, which is a detailed circuit diagram of the voltage component detecting means in the second embodiment, there is no voltage phase selecting means 212 in FIG.

 That is, the voltage component of each phase of three phases is converted at the same ratio as in Equation 1, and there is no phase change, and the value of each phase of Rv1 in order to eliminate leakage current caused by the unbalance of the resistors Rv1 and Rv2 in addition to the actual line. Is the same and it is preferable to make the value of Rv2 the same. The voltage component of each of the three phases converted by the voltage component converting means 211 is outputted to the phase detecting means 23. Phase difference between the image leakage current component Io output from the leakage current detecting means 22 and the image leakage current component Io for each voltage component of each of the three phases output by the voltage component converting means 211. Is detected and displayed on the phase difference display means (24).

The image leakage current component Io displayed on the leakage current display means 25 can be displayed as shown in Equation 2 above.

For example, the phase difference of the image leakage current Io with respect to the R phase voltage component displayed by the phase difference display means 24 is θr, and the phase difference of the image leakage current Io with respect to the S phase voltage component is θs, T phase. If the phase difference of the image leakage current (Io) with respect to the voltage component is θ t

The component of the image leakage current Io with respect to the R phase voltage component may be expressed as shown in Equation 3. In addition, the component of the image leakage current Io with respect to the S-phase voltage component may be expressed as shown in Equation 4. The component of the image leakage current Io with respect to the T phase voltage component may be expressed as shown in Equation 5.

For example, as in the example described above, the effective leakage current Irr = 1 mA due to the resistance component flowing in R phase, the reactive leakage current Icr = 60 mA due to capacitance, and the effective leakage current Irs due to the resistance component in S phase. In a three-phase wire line where = 1 mA, the reactive leakage current Ics = 20 mA due to capacitance, the effective leakage current Irt = 1 mA due to the resistance component flowing in T phase, and the reactive leakage current Ict = 20 mA due to capacitance, The value of the image leakage current detected and displayed by the leakage current detection means 22 and the leakage current display means 25 connected to the secondary side of the image current transformer 10 is Io = 76.3mA, and the voltage detection line 12, 13 and 14 and a phase difference between the image leakage current component outputted from the leakage current detecting means 22 for the voltage component of each of the three phases detected through the voltage component detecting means 22; 23) and each of the three-phase each phase detected and displayed by the phase difference display means 24 The phase difference with respect to the voltage component, that is, the phase difference with the image leakage current (Io) with respect to the voltage component of the R phase is θ r = 104.8, and the phase difference with the image leakage current (Io) with respect to the voltage component of the S phase is θ s = -15.2, and the voltage of the T phase is The phase difference with the image leakage current Io for the component is θ t = -135.2.

Substituting the equations 3 to 5 for each of the three phase phases using the values of Io, θr, θs, θt, Io for the voltage component of R phase is -19.5 + j73.8, and Io for the voltage component of S phase is 73.6. Io for the voltage component of -j20.0, T phase can be calculated as -54.1-j53.8. In addition, the left term of the value of Io is in phase with respect to the voltage, and the right term, i.e., the term j contains 90 degrees with respect to the voltage.

Next, a check is made to see if any of the three phases has a large amount of reactive leakage current Ic due to capacitance. First, confirming that each of the in-phase and 90-degree phases of the leakage current with respect to the voltage of each phase is larger, the 90-phase phase of the R phase is the largest and the in-phase of the S phase is the largest. It is common that the 90-degree phase of R phase becomes + (plus) when the reactive leakage current (Icr) of R phase is large or the effective leakage current (Irs) of S phase is large as shown in Equation 3. .

 The in phase of S phase becomes + (plus), as shown in Equation 4, when the effective leakage current Irs of the S phase is large or the reactive leakage current Icr of the R phase is large. In order to reconfirm that the Icr and Irs values identified above are the largest, verify that the in phase and the 90 degree phases of the leakage current with respect to the voltage of each phase are respectively small, the phase in phase T is the smallest and the phase 90 degrees in the T phase is the smallest. It can be seen that it is small.

As shown in Equation 5, the in phase of T phase becomes-(minus), the effective leakage current (Irr) of R phase is large, or the effective leakage current (Irs) of S phase is large, or the reactive leakage current of R phase ( It is common for Icr) to be large, and the 90-phase phase of T phase becomes-(minus), as shown in Equation 5, the reactive leakage current (Icr) of R phase is large or the reactive leakage current of S phase of S phase. Since (Ics) is large or the effective leakage current (Irs) of the S phase is large, it is invalid for the R phase to satisfy the combination of the effective and reactive leakage currents of each phase with respect to the largest and smallest values. It is understood that the divided leakage current Icr is large and the effective divided leakage current Irs of the S phase is large.

Next, when the reactive leakage current of a certain magnitude is passed in the S phase and the T phase except the R phase having the largest reactive leakage current, in the same direction as the leakage current flowing in the actual line to the primary side of the image transformer 10, the image By canceling the reactive leakage current flowing to the primary side of the current transformer 10 to calculate whether the reactive leakage current is detected on the secondary side of the current transformer 10. The j term of Equation 3 to Equation 5, i.e., the values of Ics 'and Ict' where the 90 degree phase becomes zero are as follows.

Expression 3 Equation 4 Equation 5 Icr 'calculation About-73.8 -40.0 About -107.6 Image leakage current calculation value for R phase voltage -19.5 + j0.0 -19.5 + j33.8 -19.5-j33.8 Image leakage current calculation for S phase voltage 9.8 + j16.9 39.0 + j0.0 -19.5 + j33.8 Image leakage current calculation value for T phase voltage 9.8-j16.9 -19.5-j33.8 39.0 + j0.0

In Table 2, since the effective leakage current (Irs) of the S phase corresponds to the condition of Equation 4, the reactive leakage current (Icr) having the largest R phase corresponds to 40 mA. Increasing the reactive leakage current by 40mA will cause the reactive leakage current to equilibrate.

Next, C1, C2, C3 of the compensation means 31 connected to the S and T phase voltage detection lines 13 and 14 in the leakage current compensator 30 (in the embodiment of the present invention, three capacitor elements are provided for each phase). It is configured, but not limited to three) and the contact switch (sw1r, sw2r, sw3r) of the current phase selection means 32 corresponding to the S phase and the T phase by calculating the phase voltage between the cable line 3 and the ground. ) Switch the contact switch corresponding to the active component compensation current (Ics 'and Ict') of 40mA to the leakage current compensation winding 15 side, the corresponding of the voltage detection line 12 and the compensation means 31 Image flowing between the actual cable line 3 and the ground to the primary side of the current transformer 10 through the capacitance (C1, C2, C3), the current phase selection means 32 and the leakage current compensation winding 15 In the same direction as the leakage current Io, i.e., through the image transformer 10 from the transformer 1 side of the image transformer 10, the reactive compensation current Ic 'is transferred to the ground side. Increasingly, the reactive leakage current Ic is balanced so that only the active leakage current Ir component due to the insulation resistance 9 is almost detected on the secondary side of the current transformer 10.

Then, through the leakage current compensation winding 15, the reactive compensation current Ic ', that is, in the above example, the reactive compensation currents Ics' and Ict' of the S phase and the T phase are the primary values of the current transformer 10. Detecting the image correction current (Io ') through the amplification and filtering process in the leakage current detection means 22 in the insulation detector 20 connected to the secondary side of the image current transformer 10 in the state flowing through the winding, An insulation detector 20 in which the image correction current Io 'detected by the leakage current detection means 22 is displayed on the leakage current display means 25, and the voltage detection lines 12, 13, and 14 are connected. The phase voltage component of the three-phase each phase converted by the voltage component converting means 211 in the voltage component detecting means 211 into a constant voltage, and converted by the voltage component converting means 211 into the constant voltage. Phase detecting means 23 into which the image correction current Io 'detected by the leakage current detecting means 22 is input. Phase difference θr 'of the image correction current Io' with respect to the R phase voltage component and phase difference θs' of the image correction current Io 'with respect to the S phase voltage component and the image correction current Io' with respect to the T phase voltage component Phase difference θt 'is detected and displayed on the phase difference display means 25.

When reconfirming that the phase difference θs 'with the image correction current Io' for the S phase voltage component is almost zero, or the phase difference θr 'with the image correction current Io' for the other R and T phase voltage components, When? t 'is determined to be 120 degrees or -120 degrees, the image correction current Io' detected above is applied to the effective leakage current Ir flowing by the insulation resistance 9 flowing between the actual cable line 3 and the earth. The reactive current leakage current (Ic) almost does not flow to the primary side of the current transformer 10, so that the image current transformer 10 is equal to 2 of the current transformer 10 by a small amount of the effective current leakage current Ir. Since it is induced on the vehicle side, the effective resistance leakage current Ir flowing to the ground can be detected by the insulation resistance 9 which is directly related to the earth leakage with high sensitivity, and the phase in which the insulation is the worst, that is, the earth leakage can be identified. Intensive for awards that are being shorted As a result, it is possible to save time by investigating and evaluating the leakage current, and additionally, the information of the phase with the largest capacitance and the amount of the reactive leakage current (Ic) are also known. It becomes possible. On the other hand, if the θs' with the image correction current Io 'for the S phase voltage component becomes substantially zero, the reactive compensation current Ics' for the S phase and the reactive correction current for the T phase ( Ict ') is repeatedly carried out in the state of flowing the leakage current compensating means 15, and in the state where the reactive component leakage current Ic is hardly detected on the secondary side of the current transformer 10, It is preferable to detect and display the effective leakage current Ir.

In the example described above, when the reactive leakage current Ic due to the capacitance of one of the three phases flows largely, the detection of the residual dispersion correction current Ic 'is performed for two phases with a small amount of the reactive leakage current Ic. Although the current flows in the same direction as the current flow direction of the image leakage current Io flowing between the actual cable line 3 and the ground, but if the reactive leakage current Ic is large due to the capacitance of two phases in three phases, Detecting and calculating the reactive correction current Ic 'of the phase where the reactive leakage current Ic is small, and flowing it in a direction opposite to the current flow direction of the image leakage current Io flowing between the actual cable line 3 and the earth, or Alternatively, it is preferable to use a method of confirming whether the image correction current Io is almost zero by flowing the correction current to the smallest phase first and then to the next small phase.

(Third Embodiment)

Next, FIGS. 15 and 17, which are the second embodiment of the insulation detector of the insulation detection system of FIG. 6 and the present invention, will be described as a third embodiment for explaining the insulation detection method and the leakage current compensator of the present invention.

The configuration of FIG. 6 is the same as that of FIGS. 4 and 5 described above, but in FIG. 4, which is the first embodiment, voltage detection lines 12 and 13 connected to detect voltage components of three-phase respective phases between the cable line 3 and the ground. , 14 is connected to the leakage current compensator 30, and is connected to the ground side of the current phase selection means 32 through the capacitances C1, C2, C3 in the compensation capacitance means 31. The other contact point of 32 is connected to the leakage current compensation winding 15 connected to the ground through the primary side of the image transformer 10 from the load 4 of the image transformer 10 to the transformer 1 side and connected to ground, thereby making it possible to compensate for the invalid distribution. The current flow direction of the current c 'is configured in a direction opposite to the flow direction of the image leakage current Io between the cable line 3 and the ground. In the second embodiment of FIG. 5, voltage detection lines 12, 13, and 14 connected to detect the voltage component of each of the three-phase respective phases between the cable line 3 and the ground are connected to the leakage current compensator 30 to compensate for ( 31 is connected to the ground side of the current phase selection means 32 via the capacitances C1, C2, C3. The other contact point of the current phase selection means 32 is a leakage current compensation winding 15 connected to the ground through the primary side of the current transformer 10 from the transformer 1 of the image transformer 10 to the load 4 side. The current flow direction of the reactive compensation current c 'is connected in the same direction as the flow direction of the image leakage current Io between the cable line 3 and the ground.

On the other hand, in the third embodiment, in FIG. 6, voltage detection lines 12, 13, and 14 connected to detect the voltage component of each of the three phases between the line 3 and the ground are connected to the leakage current compensator 30 to compensate. It is connected to the ground side of the current phase selection means 32 via the capacitances C1, C2, C3 in the melting means 31. The other contact point of the current phase selection means 32 passes through the primary side of the image transformer 10 from the load 4 of the image transformer 10 to the transformer 1 side in the flow direction of the reactive compensation current Ic '. To flow to ground or to flow through the primary side of the image transformer 10 from the transformer 1 side of the image transformer 10 to the load 4 side to the ground, i.e., an invalid portion flowing between the cable line 3 and the ground. It is connected to the leakage current compensation winding 15 which has passed through the primary side of the image current transformer 10 through a ground direction selecting means 33 which can select whether to flow in the opposite direction to the leakage current Ic or in the same direction. Is different.

As described in the first and second embodiments, in the detection and detection of the insulation state of the cable line 3, the earth-to-earth insulation of the wire line 3 including the load 4 is precisely performed even in the unbalanced state of the capacitance. In order to detect the state with high sensitivity, the reactive current leakage current Ic due to the capacitance flows very small in the image current transformer 10 such as ZCT which detects the component of the image leakage current Io flowing between the grounds. 10), only the effective leakage current Ir component due to the insulation resistance is required to flow. In the first embodiment described above, the reactive correction current Ic 'is applied to the phase with the largest reactive leakage current Ic. Is detected on the secondary side of the image transformer 10 by flowing an invalid portion correcting current Ic 'such as an invalid portion leakage current Ic due to the capacitance flowing to the primary side of the image transformer 10 in the opposite direction. Leakage current component (Ic) Almost not appearing.

In the second embodiment, the invalid partial correction current Ic 'is invalid due to the capacitance flowing to the primary side of the image transformer 10 for the other two phases except for the phase having the largest reactive partial leakage current Ic. Although the reactive correction current Ic 'such as the divided leakage current Ic flows in the same direction, the leakage current component Ic due to the capacitance detected on the secondary side of the image current transformer 10 is hardly shown. In the third embodiment of the invention, the functions of the first embodiment and the second embodiment are combined, and the reactive leakage current between the cable line 3 and the ground is selected depending on the selection position of the switch sw4 of the ground direction selecting means 33. It is decided whether to flow in the direction opposite to the direction of Ic or in the same direction so that the leakage current component Ic due to the capacitance detected on the secondary side of the image current transformer 10 is hardly shown.

As described above, an image current transformer 10 such as ZCT for detecting a component of the image leakage current Io is provided in the middle of the wire line 3 or the ground line 5 of the transformer 1, and the phase difference? Voltage detection lines (12, 13, 14) for detecting the voltage components of each phase of the wire line (3) necessary for detecting the phase difference, and the phase difference of each phase of each of the three phases and the component size of the image leakage current (Io) The secondary side of the image current transformer 10 and the voltage detection lines 12, 13, and 14 are connected to an insulation detector 20 for detecting (θ). The insulation detector 20 is shown in detail in FIG. 15. The phase leakage current (Io) detected by the insulation detector 20 and the phase difference θ by each phase of each of the three phases indicate that the reactive leakage current caused by the capacitance among the three phases flows most or the smallest. A leakage current compensator 30 for manipulating the capacitance of the phase to be judged so that the capacitance of the three phases is balanced so that the reactive leakage current Ic due to the capacitance is not detected on the secondary side of the current transformer 10. The reactive compensation current Ic 'caused by the capacitance operated in the leakage current compensator 30 is the same or opposite to the flow of the leakage current passed through the three-phase package (or the ground line of the transformer) of the image transformer 10. The leakage current compensation winding means 15 connected through the ground direction selecting means 33 for selecting to flow in the direction to flow the reactive compensation current Ic 'is connected to the image current transformer 10 with the test line of the image current transformer. Use a separate auxiliary winding. The leakage current compensator 30 has compensation means 31 for making various reactive compensation currents Ic 'and reactive compensation current Ic' flowing through the compensation means 31 to the ground side. The current phase selection means 32 which can select whether to flow or to the leakage current compensation winding 15 connected through the ground direction selection means 33 is configured for each phase, and the current phase selection means 32 Through the reactive current compensation current Ic 'for flowing into the leakage current compensation winding 15 through the current in the opposite direction to the flow direction of the reactive leakage current Ic flowing between the actual cable line 3 and the ground or The ground direction selecting means 33 can select whether or not to flow. When the current phase selection means 32 do not operate, the current flowing through the compensation means 31 flows to the ground side, and the values of the capacitances C1, C2, and C3 may be different. The combined capacitance (C1 + C2 + C3) values for each of the three phases are configured to be substantially the same so that the ground or the ground direction selection means are provided through the voltage detection lines 12, 13 and 14 and the compensation means 31. (33) and the reactive leakage current flowing to the ground through the leakage current compensation winding 15 are preferably configured to be balanced.

An example is demonstrated. The voltage between the three-phase cable line 3 and the ground described in the first and second embodiments is 220 V 60 Hz, and the effective divided leakage current flowing through the insulation resistance 9 between each phase and the ground is Rr = Irr = 1 mA, S phase is Irs = 40mA, T phase is Irt = 1mA, and the reactive leakage current flowing through the capacitance (8) between each of three phases and the ground, that is, R phase is Icr = 60mA, S phase is Ics = 20mA, T phase is Ict = 20mA In the case of, the reactive leakage current (Icr) of the R phase flows the most and the reactive leakage current (Ics and Ict) of the other two phases (S phase and T phase) is very small compared to the R phase, so Leakage current from the ground direction selecting means 33 so as to cancel the reactive leakage current (Icr ') in the direction opposite to the reactive leakage current (Ic) direction to cancel the reactive leakage current component passing through the image current transformer (10). Z1 on the load side of the image transformer 10 of the compensation winding 15 is connected to the current phase selecting means 32, and the image current of the leakage current compensation winding 15 is connected. Sw4 is selected so that z2 on the transformer side of (10) is connected to the ground side, so that the reactive compensation current (Icr ') flows from the load side of the image transformer 10 to the transformer side, that is, the image leakage flowing between the actual cable line 3 and the ground. The image correction current detected on the secondary side of the image transformer 10 while flowing in the direction opposite to the current Io to cancel the reactive leakage current Ic so as not to be induced on the secondary side of the image transformer 10. By detecting (Io '), the effective leakage current (Ir) is accurately detected with very high sensitivity. In the above example, the reactive leakage current (Ic) of two phases is very large and the reactive leakage current (Ic) of one phase is very small. The phase and magnitude through which the very small reactive leakage current Ic flows are detected and calculated by the method described in the first and second embodiments, so that the reactive correction current for the voltage of the phase where the reactive residual leakage current Ic is very small. (Ic ') by operating the phase (C1, C2, C3) and the current phase selection means 32 of the phase corresponding to the compensation means (31) and the reactive correction current (Ic) in the ground direction selection means (33) ') Flow direction from the transformer side to the load side, that is, to flow in the same direction as the flow direction of the image leakage current (Io) so that the reactive component leakage current component passing through the primary side of the image transformer 10 is balanced. Therefore, the reactive side leakage current component is almost detected on the secondary side of the image transformer 10. The effective leakage current (Ir) to detect the image correction current (Io ') detected by the current transformer secondary side of the image 10 in a state so as not to accurately detect a very high sensitivity.

4, the second embodiment, FIG. 5, and the third embodiment, FIG. 6, illustrate that the secondary side connection of the transformer 1 is wired, but is also used in the delta connection. Figure 7 shows a connection diagram of another embodiment. Although the secondary connection of the transformer 1 is changed to a delta connection in FIG. 6, the leakage current compensator 30 used in FIGS. 4 and 5 may also be applied to the configuration of the leakage current compensator 30.

8 shows that the secondary side connection of the transformer 1 can be used in a non-grounding manner, and the compensation means 31 in the leakage current compensator 30 is grounded before correction in the first to third embodiments. It is an embodiment for explaining that there may be an embodiment in which the connection is connected to the leakage current compensation winding 15 or the ground direction selecting means 33 before correction.

18 and 19 show an embodiment in which the voltage converting means of Figs. 16 and 17, which are the voltage component detecting means used in Figs. In FIG. 18, the first embodiment of the converting means, there may be an embodiment in which capacitors Cv1 and Cv2 are configured in series using a capacitor instead of a resistor to use voltage components of each phase shown in Cv2. In FIG. 19, which is a second embodiment of the voltage converting means, an embodiment for explaining that the voltage can be converted even when the transformer TR is used without converting the voltage using the resistor or the capacitor. In FIG. 19, a capacitor may be used instead of the resistor Rv connected between the secondary side of the transformer TR and the ground, and a three-phase phase between the secondary side of the transformer TR and the ground may be used without using a resistor or a capacitor. There may also be an embodiment of the configuration using the voltage component. In addition, in the embodiment of the present invention, only one leakage current compensation winding 15 is used, but there may be an embodiment in which three leakage current compensation windings 15 are used for each of the three phases. In the embodiment of the present invention, the voltage component converting means 211 for detecting the voltage component is composed of the internal configuration of the insulation detector 20, but the portion having the function of the voltage component converting means 211 is formed in the insulation detector 20. There may also be embodiments configured externally. There may be an embodiment in which some functions of the leakage current detecting means 22 for detecting the image leakage current are configured outside the insulation detector 20, and instead of the phase voltage detected by the voltage detecting lines 12, 13, and 14, respectively. There may be an embodiment for detecting the line voltage in the above, and there may be an embodiment for detecting the voltage component of only one phase of the three phases by using a phase shift, and converts the three-phase voltage components by phase shifting by 120 degrees. In addition, although the embodiment of the present invention has been described with respect to the embodiment in which the installation position of the image current transformer 10 is installed in the middle of the electric wire path 3 which is intermediate between the transformer 1 and the load 4, the transformer 1 and There may be an embodiment provided in the middle of the ground line 5 of the ground (6). Although the embodiment in which the connection positions of the voltage detection lines 12, 13, and 4 are connected to the front end of the image transformer 10, that is, the transformer 1 side, has been described, the rear end of the image transformer 10, that is, the load 4, has been described. There may also be embodiments connected in the lateral direction.

(Example 4)

First, a fourth embodiment for explaining the insulation detection method, insulation detection system, and leakage current compensator of the present invention will be described with reference to FIGS. 9, 14, and 16.

In FIG. 9, the transformer 1 supplies electric power to the wire path 3 through the switch 2 as a transformer for converting voltage. Reference numeral 5 is a ground wire for connecting the neutral point of the transformer 1 to the ground 6 for safety. When insulation deterioration occurs between the cable line 3 including the load 4 and the earth while power is supplied to the load 4 through the switch 2 and the wire line 3, the insulation resistance 8 is insulated. The resistance value is lowered, and the effective leakage current Ir caused by the insulation resistance flows through the insulation resistance 9 to the ground. If only the effective leakage current Ir by the insulation resistance can be detected, the earth-to-earth insulation state of the cable line 3 can be known.

However, in the case where the cable line 3 is a long-distance line, or in the case of the cable line 3 divided into several places, the capacitance C becomes large due to the parallel synthesis of the cable-to-earth capacitance of the cable line 3. In particular, in the case where the load 4 is an electronic precision equipment, an electronic component such as a noise filter is often inserted between the input terminal and the ground to prevent noise from entering the input terminal of the load 4. Since electronic components such as noise filters have many capacitor components, a large amount of reactive leakage current (Ic) flows due to the capacitance that is 90 degrees ahead of the voltage which is not directly related to the insulation state, and the load 4 is the same as that of inverters. In the power electronic equipment which controls the equipment by using the power electronic device, the reactive leakage current (Ic) due to the capacitance flows to the ground through the capacitor included in the equipment by the high frequency when controlling the frequency or the voltage at high frequency. Or a high frequency generated in a facility such as an inverter flows through the capacitance between the cable and the ground, and the reactive leakage current (Ic) flows due to the capacitance larger than the commercial frequency, and the cable line 3 is long. Since the capacitance of the cable line 3 and the ground is combined in parallel, the longer the length of the cable line 3 is, the larger the thickness of the cable of the cable line 3 is, the larger the capacitance becomes. The reactive leakage current Ic due to the capacitance becomes large. When the reactive leakage current Ic caused by the above-mentioned capacitance flows in the same magnitude between the three-phase RST phase and the ground, the three phases are balanced, and the three-phase vector sum of the reactive leakage currents Ic due to capacitance is almost zero ( zero, but in a complex system using single-phase loads on three-phase lines or branching into multiple loads, the capacitance between three phases is difficult to balance. This unbalanced capacitance increases the reactive leakage current Ic due to the capacitance flowing between the cable line 3 and the ground.

In addition, the effective leakage current (Ir) due to the insulation resistance and the reactive leakage current (Ic) due to the capacitance flow together between the line 3 and the ground, and as described above, the earth of the line 3 To detect the image leakage current flowing to the ground to know the insulation state between the terminals, an image current transformer 10 such as ZCT is connected to the middle of the wire line 3 or the neutral point of the transformer 1 or the ground on one end of the transformer 1. Install in the middle of connected ground wire (5). Since the image current transformer 10 is represented by the vector sum of the effective divided leakage current Ir due to the insulation resistance and the reactive divided leakage current Il due to the capacitance, the insulation current is very large, that is, even if the insulation state is satisfactory. Image leakage current, which is a vector sum of Ir and Ic detected in the secondary winding of the image transformer 10, as the reactive leakage current Ic caused by the capacitance flowing to the ground due to the unbalance of the capacitance not directly related to the state increases. (Io) is largely detected.

Since the effective leakage current Ir due to the insulation resistance cannot be separated only by the magnitude of the image leakage current Io, which is the vector sum of Ir and Ic, the phase difference θ with the commercial AC voltage component of the cable line 3 is determined. The cosθ of the image leakage current Io, which is in phase with the voltage component, is the effective leakage current Ir due to the insulation resistance, and the sinθ of the image leakage current Io, which is 90 degrees out of phase with the voltage component, The method of separating the reactive leakage current (Ic) by means of a single phase is effective in single phase, but in three phases, since each of the three phases has a 120-degree phase difference, the three-phase composite image leakage current (Io) is equal to the phase component of each of the three phases. Since the phase-phase components are mixed, it is very difficult to separate the effective leakage current Ir and the reactive leakage current Ic.

In addition, the larger the reactive leakage current Ic in the state where the constant effective leakage current Ir flows, the more effective the effective leakage current Ir due to the magnetic field characteristic of the image transformer 10 on the secondary side of the image transformer 10. It is also very difficult to accurately detect the magnitude of the effective leakage current (Ir) due to the phenomenon that the magnitude does not appear.

Therefore, in order to detect and detect the insulation state of the cable line 3, in order to accurately detect the earth-to-earth insulation state of the cable line 3 including the load 4 with high sensitivity even in the unbalanced state of capacitance, the image leakage current flowing between the earths The reactive current leakage current Ic caused by the capacitance flows very small in the image current transformer 10 such as ZCT that detects the component of Io, and the image current transformer 10 has an effective leakage current Ir due to insulation resistance. Since only the component flows, it is necessary to flow the reactive compensation current Ic 'such as the reactive leakage current (Ic) due to the capacitance flowing in the primary winding of the image transformer 10 in the opposite direction to flow the current transformer ( The leakage current component (Ic) due to the capacitance detected in the secondary winding of 10) can be almost suppressed.However, as described above, the three-phase connection of the secondary side of the transformer 1, in particular, 3-phase each phase The effective leakage current due to the insulation resistance flowing in the primary winding of the image current transformer 10 is affected by the leakage current component flowed by the insulation resistance 9 and the capacitance 8 to the phase leakage current Io component. The effective compensation current Ir 'such as (Ir) is also flowed in the opposite direction to more accurately determine whether the image leakage current Io detected in the secondary winding of the image transformer 10 becomes zero. The effective leakage current Ir and the invalid leakage current Ic flowing between the cable line 3 and the ground can be detected.

As described above, an image current transformer 10 such as ZCT for detecting a component of the image leakage current Io is provided in the middle of the wire line 3 or the ground line 5 of the transformer 1, and the phase difference? The voltage detection lines 12, 13, and 14 for detecting the voltage components of each phase of the wire line 3 necessary for detecting the phase difference are used, and the phase difference between each phase of each phase and the three phases of the image leakage current Io The secondary side of the image current transformer 10 and the voltage detection lines 12, 13, and 14 are connected to an insulation detector 20 for detecting θ). The insulation detector 20 is shown in detail in FIG. In addition, the reactive leakage current due to the three-phase capacitance and the effective leakage current due to the insulation resistance flow most due to the phase difference θ for each phase of the image leakage current Io and the three phases detected by the insulation detector 20. The capacitance and resistance of the three phases are balanced by manipulating the capacitance and the resistance from the phase where it is judged to be high, so that the reactive leakage current Ir due to the capacitance and the effective leakage current Ir due to the insulation resistance are determined by the image current transformer ( The reactive current compensation current Ic 'by the leakage current compensator 30 and the capacitance operated by the leakage current compensator 30 and the effective distribution compensation current due to the resistance so as not to be detected by the secondary winding of 10). The leakage current compensation winding means 15 for causing Ir ') to flow in a direction opposite to the flow of the leakage current passed through the three-phase package (or the ground wire of the transformer) of the image transformer 10 is connected to the image transformer 10. The test line of the image transformer Use a separate auxiliary winding. The leakage current compensator 30 includes a compensating capacitance part 311 for making various reactive compensation currents Ic 'and a compensating resistance part for making various effective compensating currents Ir' ( Compensation means 31 composed of 312, and can be selected to flow to the ground side or to the leakage current compensation winding (15) side of the reactive compensation current (Ic ') flowing through the compensation means (31) Current phase selection consisting of an effective partial direction selecting section 321 and an effective partial direction selecting section 322 that can select whether to flow an effective divided compensating current Ir 'to the ground side or the leakage current compensating winding 15 side. Means 32 are configured. Values of the capacitances C1, C2, and C3 of the compensation capacitance unit 311 may be different, and the combined capacitances C1 + C2 + C3 for each of the three phases have the same value. The reactive leakage current flowing through the detection lines 12, 13 and 14 and the compensation means 31 to the ground or through the leakage current compensation winding 15 to the ground is preferably configured to be balanced. Values of the capacitances r1, r2, and r3 of the compensation resistor unit 312 may vary, and the combined resistance (r1 + r2 + r3) values of each of the three phases may be configured to be the same. Preferably, the reactive leakage current flowing to ground through the 12, 13, 14 and the compensation means 31 or to the ground through the leakage current compensation winding 15 is balanced. The capacitance amount and the resistance amount of the capacitor portion 311 and the compensation resistor portion 312 are not limited to three.

The voltage between the three-phase cable line (3) and the ground is 220V 60 Hz, and the effective leakage current flowing through the insulation resistance (9) between each phase and the ground is: R phase is Irr = 1 mA, S phase is Irs = 40 mA, and T phase is Irt = 1 mA. An example of an ineffective leakage current flowing in the capacitance 8 between each of the three phases and the ground, i.e., an electric wire path in which the R phase is Icr = 60 mA, the S phase is Ics = 20 mA, and the T phase is Ict = 20 mA will be described.

The vector sum of the effective leakage current flowing through the actual insulation resistance 9 is 39 mA, and the vector sum of the reactive leakage current flowing through the capacitance is 40 mA. However, the leakage current flowing between the cable line and the ground, i.e., the leakage current flowing through the image current transformer is about 76mA, and detecting only 76mA did not accurately determine the effective leakage current due to the insulation resistance flowing between the cable line and the ground. The present invention is to implement a method and a device that can accurately detect the effective leakage current Ir = 39mA, and Ic = 40mA generated due to the large amount of reactive leakage current caused by the capacitance of R phase compared to other phases. The voltage component of the R phase in the direction opposite to the current flow of the image leakage current flowing between the actual line 3 and the earth as the primary winding of the image transformer so that the value detected at the secondary side of the image transformer 10 becomes almost zero. Ir = 39mA, which is generated due to the fact that the reactive compensation current Ic '= 40mA having a phase difference of 90 degrees and the effective leakage current due to the insulation resistance of the S phase flows in comparison with the other phases, is detected on the secondary side of the current transformer 10. It is a primary winding of the image transformer so that the value is almost zero. It has a phase difference equal to the voltage component of the S phase in the direction opposite to the current flow of the image leakage current flowing between the actual line 3 and the earth. When the effective compensation current Ir '= 39mA is applied, it is checked whether the image compensation current Io' detected at the secondary side of the current transformer 10 becomes almost zero, so that the effective leakage current Ir is 39mA in S phase. It is to detect the fact that the reactive leakage current Ic flows 40 mA in R phase.

When the image leakage current Io detected by the secondary side of the current transformer 10 is input to the insulation detector 20 as shown in FIG. 14, the leakage current is amplified and filtered by the leakage current detection means 22. The display means 25 displays the image leakage current Io value, and the leakage current component Io amplified and filtered by the leak flow detection means 22 is outputted to the phase detection means 23. In the state, when the voltage component of the three-phase each phase between the ground of the cable line 3 input by the voltage detection lines 12, 13, 14 is input to the insulation detector 20, as shown in FIG. In the voltage component detecting means 21 of the same embodiment, the resistances Rv1 and Rv2 of the voltage component converting means 211 are converted as in Equation 1.

 That is, the voltage component of each phase of three phases is converted at the same ratio as in Equation 1, and there is no phase change, and the value of each phase of Rv1 in order to eliminate leakage current caused by the unbalance of the resistors Rv1 and Rv2 in addition to the actual line. Is the same and it is preferable to make the value of Rv2 the same. The voltage component of each of the three-phase phases converted by the voltage component converting means 211 is a voltage component of the R phase when the switch sw_v of the voltage phase selecting means 212 is selected to the r side, and the switch sw_v is moved to the s side. If it is selected, the voltage component of the S phase is output to the phase detecting means 23 when the switch sw_v is selected to the t side. The image leakage current component Io output from the leakage current detecting means 22 and the image leakage current component Io for the voltage component of the phase selected by the voltage phase selection means 212 and the voltage component of each of the three phases. The phase difference is detected and displayed on the phase difference display means 24.

The image leakage current component Io displayed on the leakage current display means 25 can be displayed as shown in Equation 2 above.

For example, the phase difference of the image leakage current Io with respect to the R phase voltage component displayed by the phase difference display means 24 is θr, and the phase difference of the image leakage current Io with respect to the S phase voltage component is θs, T phase. If the phase difference of the image leakage current (Io) with respect to the voltage component is θ t

The component of the image leakage current Io with respect to the R phase voltage component is expressed by Equation 3, and the component of the image leakage current Io with respect to the S phase voltage component is expressed by Equation 4. In addition, the component of the image leakage current Io with respect to the T phase voltage component is expressed as in Equation 5.

For example, as described above, the effective leakage current Irr = 1 mA due to the resistance component flowing in R phase, the reactive leakage current Icr = 60 mA due to capacitance, and the effective leakage current Irs due to the resistance component in S phase. In a three-phase wire line where = 1 mA, the reactive leakage current Ics = 20 mA due to capacitance, the effective leakage current Irt = 1 mA due to the resistance component flowing in T phase, and the reactive leakage current Ict = 20 mA due to capacitance, The value of the image leakage current detected and displayed by the leakage current detection means 22 and the leakage current display means 25 connected to the secondary side of the image current transformer 10 is Io = 76.3mA, and the voltage detection line 12, 13 and 14 and the phase difference means of the phase difference between the image leakage current component output from the leakage current detecting means 22 for the voltage component of each of the three phases detected through the voltage component detecting means 22; 23) and detecting and displaying three phases of each phase through the phase difference display means 24. The phase difference with respect to the voltage component, that is, the phase difference with the image leakage current (Io) with respect to the voltage component of the R phase is θ r = 104.8, the phase difference with the image leakage current (Io) with respect to the voltage component of the S phase is θ s = -15.2, and the voltage of the T phase The phase difference with the image leakage current Io for the component is θ t = -135.2.

Substituting the equations 3 to 5 for each of the three phase phases using the values of Io, θr, θs, θt, Io for the voltage component of R phase is -19.5 + j73.8, and Io for the voltage component of S phase is 73.6. Io for the voltage component of -j20.0, T phase can be calculated as -54.1-j53.8. In addition, the left term of the value of Io is in phase with respect to the voltage, and the right term, i.e., the term j contains 90 degrees with respect to the voltage.

Next, an operation is performed to check whether any of the three phases has a large amount of reactive leakage current Ic due to capacitance and effective leakage current Ir due to insulation resistance. First, confirming that each of the in-phase and 90-degree phases of the leakage current with respect to the voltage of each phase is larger, the 90-phase phase of the R phase is the largest and the in-phase of the S phase is the largest. It is common that the 90-degree phase of R phase becomes + (plus) when the reactive leakage current (Icr) of R phase is large or the effective leakage current (Irs) of S phase is large. The in phase of S phase becomes + (plus), as shown in Equation 4, when the effective leakage current Irs of the S phase is large or the reactive leakage current Icr of the R phase is large. In order to reconfirm that the Icr and Irs values identified above are the largest, verify that the in phase and the 90 degree phases of the leakage current with respect to the voltage of each phase are respectively small, the phase in phase T is the smallest and the phase 90 degrees in the T phase is the smallest. It can be seen that it is small. As shown in Equation 5, the in phase of T phase becomes-(minus), the effective leakage current (Irr) of R phase is large, or the effective leakage current (Irs) of S phase is large, or the reactive leakage current of R phase ( It is common for Icr) to be large, and the 90-phase phase of T phase becomes-(minus), as shown in Equation 5, the reactive leakage current (Icr) of R phase is large or the reactive leakage current of S phase of S phase. Since (Ics) is large or the effective leakage current (Irs) of the S phase is large, it is invalid for the R phase to satisfy the combination of the effective and reactive leakage currents of each phase with respect to the largest and smallest values. It is understood that the divided leakage current Icr is large and the effective divided leakage current Irs of the S phase is large.

Next, when the reactive leakage current of a certain magnitude flows in the opposite direction to the leakage current flowing in the actual line to the primary side of the image transformer 10, the primary side of the image transformer 10 has the largest reactive phase leakage current. By canceling the reactive leakage current flowing in the flow to the secondary side of the current transformer 10 to calculate whether the reactive leakage current is not detected. The j term of Equation 3 to Equation 5, i.e., calculates the value of Icr 'that becomes 90 degrees phase is zero.

Expression 3 Equation 4 Equation 5 Icr 'calculation About-73.8 -40.0 About -107.6 Image leakage current calculation value for R phase voltage -19.5 + j0.0 -19.5 + j33.8 -19.5-j33.8 Image leakage current calculation for S phase voltage 9.8 + j16.9 39.0 + j0.0 -19.5 + j33.8 Image leakage current calculation value for T phase voltage 9.8-j16.9 -19.5-j33.8 39.0 + j0.0

In Table 3, since the effective leakage current (Irs) of the S phase corresponds to the condition of Equation 4, the reactive compensation current (Icr ') for the R phase is 40 mA and the effective component for the S phase. The compensation current Irs' is 39 mA.

Next, C1, C2, C3 of the compensation capacitance unit 311 in the compensation means 31 connected to the R phase, that is, the voltage detection line 12 in the leakage current compensator 30 (for each phase in the embodiment of the present invention). It is composed of three condenser elements, but not limited to three.) The phase voltage between the cable line 3 and the ground is calculated to be invalid among the contact switches sw1r, sw2r, and sw3r of the current phase selection means 32. Switching means 31 for switching the contact switches made such that the minute compensation current Icr 'is 40 mA to the leakage current compensation winding 15 side, and also being connected to the S-phase voltage detection line 13 in the leakage current compensator 30 R1, r2, r3 of the compensating resistor part 312 (in the embodiment of the present invention, each resistor consists of three resistance elements, but not limited to three) and the wire path 30 and the compensation current between the earth By switching the contact switches made such that (Irs') is 39 mA to the leakage current compensation winding 15 side, The distributed compensation current Icr 'includes the voltage detection line 12, the corresponding capacitances C1, C2, C3 in the compensation means 31, and an invalid partial direction selecting part 321 in the current phase selection means 32. And the effective compensating current Irs' include the voltage detecting line 13, the corresponding resistors r1, r2, r3 in the compensating means 31 and the effective part selecting portion in the current phase selecting means 32. 322 and the leakage current compensation winding 15 to the primary side of the current transformer 10 in a direction opposite to the image leakage current Io flowing between the actual cable line 3 and the ground, that is, of the image current transformer 10. From the load side, it passes through the image current transformer 10 and flows to the ground side, and the reactive leakage current Ir and the effective leakage current Ir are canceled, and the image leakage current Io component is almost on the secondary side of the current transformer 10. Will not be detected.

Next, the reactive compensation current Ic 'of the R phase, in this example, flows through the leakage current compensation winding 15 to the primary winding of the image transformer 10. In the example, the active side compensation current Ir ', that is, in the example, the secondary side of the image current transformer 10 is connected while the active phase compensation current Irs' of the S phase flows to the primary winding of the image current transformer 10. The leakage current detection means 22 in the insulation detector 20 detects the image correction current Io 'through amplification and filtering, and detects the image correction current Io' detected by the leakage current detection means 22. In the leakage current display means 25, and in the voltage component conversion means 211 in the voltage component detection means 21 in the insulation detector 20 to which the voltage detection lines 12, 13, 14 are connected. The phase voltage of each phase is converted into a constant voltage and converted by the voltage component converting means 211. The phase voltage of each of the three phases is switched to the r side in the three-phase sequence by sw_v switch in the voltage phase selection means 212 to detect the voltage component of the R phase, and the R phase detected by the voltage phase selection means 212. The phase detection means 23, to which the voltage component and the image correction current Io 'detected by the leakage current detecting means 22 is input, detects the phase difference θr' of the image correction current Io 'with respect to the R phase voltage component. Then, the phase difference θr 'of the R phase detected by the phase detection means 23 is displayed. Next, the sw_v switch in the voltage phase selecting means 212 is switched to the s side to detect the voltage component for the S phase, and the voltage component of the S phase detected by the voltage phase selecting means 212 and the leakage current detecting means ( Phase detection means 23 to which the image correction current Io 'detected in 22) is inputted detects the phase difference θs' of the image correction current Io' with respect to the S-phase voltage component, and the phase detection means 23 The phase difference θs' detected in S phase is displayed. Next, the sw_v switch in the voltage phase selecting means 212 is turned to the t side to detect a voltage component for the T phase, and the voltage phase selecting means 212 detects it. Phase difference θt of the image correction current Io 'with respect to the T phase voltage component in the phase detecting means 23 to which the voltage component of the phase T phase and the image correction current Io' detected by the leakage current detecting means 22 are input. 'Phase, and the phase difference of the S phase detected by the phase detection means 23 It represents a t '.

When the image correction current Io 'and the phase differences θr', θs ', and θt' for the three-phase R, S, and T-phase voltage components detected above are confirmed to be almost zero, respectively, (Irs ') = 39 mA corresponds to the effective leakage current (Ir) which is directly related to the leakage current, and the reactive leakage current (Icr') = 40 mA is not related to the leakage current. Ic), and it is possible to check the phase (S phase in the above example) in which the insulation is the worst, so that it is possible to intensively investigate and take measures of the leakage source. In addition, it is possible to save time in leakage inspection and measures, and additionally, it is possible to know information on the phase having the largest capacitance and the amount of the reactive leakage current Ic. On the other hand, if the image correction current (Io ') and the phase differences θr', θs 'and θt' for the three-phase R, S, and T phase voltages do not become substantially zero, the above-described operation is repeated. It is preferable to repeat the correction operation so that the image correction current Io 'and the phase differences θr', θs ', and θt' for the three-phase R, S, and T phase voltages become almost zero, respectively.

In the above-described example, the effective leakage current (Ir) or the reactive leakage current (Ic) when the effective leakage current (Ir) due to the insulation resistance of one of the three phases or the reactive leakage current (Ic) due to the capacitance flows large. ) Is calculated by detecting and calculating the effective differential compensation current Ir 'or the reactive differential correction current Ic', and the current flow direction of the image leakage current Io flowing between the actual cable line 3 and the earth However, if the effective leakage current (Ir) due to the insulation resistance of two phases of the three phases or the reactive leakage current (Ic) due to the capacitance flows largely, the effective leakage current (Ir) or invalid leakage is caused. The two phases of the large current Ic are simultaneously detected and calculated by the effective portion correcting current Ir 'or the reactive portion correcting current Ic', and thus the image leakage current Io flowing between the actual cable line 3 and the ground is calculated. To flow in the direction opposite to the current flow direction, or It is preferable to use a method of checking whether the image correction current Io is almost zero by flowing the correction current first for the largest phase and then the correction current for the next small phase.

(Example 5)

Next, FIGS. 10, 15, and 17 will be described as a fifth embodiment for explaining the insulation detection method, insulation detection system, and leakage current compensator of the present invention.

The configuration of FIG. 10 is substantially the same as that of FIG. 9 described above, but in the fourth embodiment of FIG. 9, the output from the current phase selecting means 32 is the primary side of the image transformer 10 from the load 4 to the transformer 1 side. The current flow direction of the image compensation current Io 'is connected in the opposite direction to the flow direction of the image leakage current Io between the cable line 3 and the ground by being connected to the leakage current compensation winding 15 connected to ground through the circuit. do. On the other hand, in FIG. 10, the fifth embodiment, the output of the current phase selecting means 32 is a leakage current compensation connected to the ground by passing the image transformer 10 through the primary side from the transformer 1 to the load 4 side. The current flow direction of the image correction current Io 'connected to the winding 15 is different in that it is configured in the same direction as the flow direction of the image leakage current Io between the cable line 3 and the ground.

As described in the fourth embodiment, in detecting and detecting the insulation state of the wire passage 3, even if the capacitance and the insulation resistance are unbalanced, the earth-to-earth insulation state of the wire passage 3 including the load 4 can be accurately measured. In order to detect with high sensitivity, the image leakage current Io due to capacitance and insulation resistance flows very small to the image current transformer 10 such as ZCT which detects the component of the image leakage current Io flowing between the grounds. 10, it is necessary to make the image leakage current Io almost not flow. In the fourth embodiment described above, the image leakage current Io flowing the image correction current Io 'to the primary side of the image transformer 10 is described. In the opposite direction.

However, in the fifth embodiment, the image correction current Io 'is applied to the other two phases except for the phase where the reactive leakage current Ic and the effective leakage current Ir are the largest. The image leakage current Io flowing in the same direction as that flowing in the vehicle side flows in the same direction so that the image leakage current Io component detected on the secondary side of the image current transformer 10 hardly appears.

As described above, an image current transformer 10 such as ZCT for detecting a component of the image leakage current Io is provided in the middle of the wire line 3 or the ground line 5 of the transformer 1, and the phase difference? Voltage detection lines (12, 13, 14) for detecting the voltage components of each phase of the wire line (3) necessary for detecting the phase difference, and the phase difference of each phase of each of the three phases and the component size of the image leakage current (Io) The secondary side of the image current transformer 10 and the voltage detection lines 12, 13, and 14 are connected to an insulation detector 20 for detecting (θ). The insulation detector 20 is shown in detail in FIG. 15. In addition, the phase leakage current Io detected by the insulation detector 20 and the phase capacitance of each of the three phases are determined by the phase difference θ. The three-phase electrostatic capacitance is balanced so that the reactive leakage current (Ic) due to the capacitance and the effective leakage current due to the three-phase insulation resistance due to the phase difference (θ) for each of the three phases and the image leakage current (Io) Is operated so that the insulation resistance of the three phases is balanced by manipulating the resistance of the phase other than the phase that is determined to flow the most, so that the effective leakage current Ir due to the insulation resistance is not detected on the secondary side of the current transformer 10. The effective compensation current Ir 'caused by the leakage current compensator 30 and the reactive compensation current Ic' caused by the capacitance operated in the leakage current compensator 30 and the resistance operated by the leakage current compensator 30. ) The leakage current compensation winding means 15 for flowing in the same direction as the flow of the leakage current passed through the three-phase package (or the ground wire of the transformer) of the image transformer 10 is used to test the image transformer 10 with the image transformer 10. Use a wire or use a separate auxiliary winding.

The voltage between the three-phase cable line (3) and the ground is 220V 60Hz, and the effective leakage current flowing through the insulation resistance (9) between each phase and the ground is: R phase is Irr = 1mA, S phase is Irs = 40mA, and T phase is Irt = 1mA. An example of an ineffective leakage current flowing in the capacitance 8 between each of the three phases and the ground, i.e., an electric wire path in which the R phase is Icr = 60 mA, the S phase is Ics = 20 mA, and the T phase is Ict = 20 mA will be described.

The vector sum of the effective leakage current flowing through the actual insulation resistance 9 is 39 mA, and the vector sum of the reactive leakage current flowing through the capacitance is 40 mA. However, the leakage current flowing between the cable line and the ground, i.e., the leakage current flowing through the image current transformer is about 76mA, and detecting only 76mA did not accurately determine the effective leakage current due to the insulation resistance flowing between the cable line and the ground. The present invention is to implement a method and apparatus for accurately detecting the effective leakage current Ir = 39mA, and additionally to implement a method and apparatus for accurately detecting the reactive leakage current Ic = 40mA. . It demonstrates in detail below.

When the image leakage current Io detected by the secondary side of the image transformer 10 is inputted to the insulation detector 20 as shown in FIG. 15, the leakage current display means amplifies and filters the leakage current through the leakage current detection means 22. The leakage current component (Io) displayed by the means (25) and amplified and filtered by the leakage flow detection means (22) is outputted to the phase detection means (23). In FIG. 16, when the voltage component of the three-phase each phase between the grounds of the wire line 3 input by the voltage detection lines 12, 13, and 14 is input to the insulation detector 20 as shown in FIG. In the example voltage component detecting means 21, the resistances Rv1 and Rv2 of the voltage component converting means 211 are converted as in Equation 1 above.

 That is, the voltage component of each phase of three phases is converted at the same ratio as in Equation 1, and there is no phase change, and the value of each phase of Rv1 in order to eliminate leakage current caused by the unbalance of the resistors Rv1 and Rv2 in addition to the actual line. Is the same and it is preferable to make the value of Rv2 the same. The voltage component of each of the three phases converted by the voltage component converting means 211 is outputted to the phase detecting means 23. The phase difference between the image leakage current component Io output from the leakage current detecting means 22 and the image leakage current component Io for each voltage component of each of the three phases output by the voltage component converting means 211 is determined. It detects and displays it on the phase difference display means 24.

The image leakage current component Io displayed on the leakage current display means 25 can be displayed as shown in Equation 2 above.

For example, the phase difference of the image leakage current Io with respect to the R phase voltage component displayed by the phase difference display means 24 is θr, and the phase difference of the image leakage current Io with respect to the S phase voltage component is θs, T phase. If the phase difference of the image leakage current (Io) with respect to the voltage component is θ t

The component of the image leakage current Io with respect to the R phase voltage component may be expressed as in Equation 3, and the component of the image leakage current Io with respect to the S phase voltage component may be represented as in Equation 4. The component of the image leakage current Io with respect to the T phase voltage component may be expressed as shown in Equation 5.

For example, as described above, the effective leakage current Irr = 1 mA due to the resistance component flowing in R phase, the reactive leakage current Icr = 60 mA due to capacitance, and the effective leakage current Irs due to the resistance component in S phase. = 1 mA and reactive leakage current Ics = 20 mA due to capacitance. In a three-phase wire line having an effective leakage current Irt = 1 mA by a resistance component flowing in a T phase and an invalid leakage current Ict = 20 mA by a capacitance, the leakage current detection means connected to the secondary side of the current transformer 10 ( 22) and the value of the image leakage current detected and displayed by the leakage current display means 25 is Io = 76.3 mA, and is detected through the voltage detection lines 12, 13, and 14 and the voltage component detection means 22. The phase difference with the image leakage current component outputted from the leakage current detecting means 22 with respect to the voltage component of each of the three phase phases detected is detected and displayed by the phase detecting means 23 and the phase difference displaying means 24. The phase difference with respect to the voltage component of each phase, that is, the phase difference with the image leakage current (Io) with respect to the voltage component of the R phase, is θ r = 104.8, and the phase difference with the image leakage current (Io) with respect to the voltage component of the S phase is θ s = -15.2, The phase difference with the image leakage current Io for the voltage component of the T phase is θ t = -135.2. .

Substituting the equations 3 to 5 for each of the three phase phases using the values of Io, θr, θs, θt, Io for the voltage component of R phase is -19.5 + j73.8, and Io for the voltage component of S phase is 73.6. Io for the voltage component of -j20.0, T phase can be calculated as -54.1-j53.8. In addition, the left term of the value of Io is in phase with respect to the voltage, and the right term, i.e., the term j contains 90 degrees with respect to the voltage.

Next, an operation is performed to check whether any of the three phases has an effective partial leakage current Ic due to capacitance and an effective partial leakage current Ir due to insulation resistance. First, confirming that each of the in-phase and 90-degree phases of the leakage current with respect to the voltage of each phase is larger, the 90-phase phase of the R phase is the largest and the in-phase of the S phase is the largest. It is common that the 90-degree phase of R phase becomes + (plus) when the reactive leakage current (Icr) of R phase is large or the effective leakage current (Irs) of S phase is large. The in phase of the phase S becomes + (plus), as shown in Equation 4, when the effective phase leakage current Irs of the S phase is large or the reactive leakage current Icr of the R phase is large. Next, in order to reconfirm that the Icr and Irs values identified above are the largest, confirm that each of the in-phase and 90-degree phases of the leakage current with respect to the voltage of each phase is smaller, the in-phase portion of the T phase is the smallest and the 90-phase phase of the T phase. You can see that the minute is the smallest. As shown in Equation 5, the in phase of T phase becomes-(minus), the effective leakage current (Irr) of R phase is large, or the effective leakage current (Irs) of S phase is large, or the reactive leakage current of R phase ( It is common that Icr) is large, and the 90-phase phase of T phase becomes-(minus), as shown in Equation 50. The reactive leakage current (Icr) of R phase is large or the reactive leakage current of S phase of S phase is large. Since (Ics) is large or the effective leakage current (Irs) of the S phase is large, it is invalid for the R phase to satisfy the combination of the effective and reactive leakage currents of each phase with respect to the largest and smallest values. It is understood that the divided leakage current Icr is large and the effective divided leakage current Irs of the S phase is large.

Next, when the reactive leakage current of a certain magnitude is passed in the S phase and the T phase except the R phase having the largest reactive leakage current, in the same direction as the leakage current flowing in the actual line to the primary side of the image transformer 10, the image By canceling the reactive leakage current flowing to the primary side of the current transformer 10 to calculate whether the reactive leakage current is detected on the secondary side of the current transformer 10. The j term of Equation 3 to Equation 5, i.e., the values of Ics 'and Ict' where the 90 degree phase becomes zero are as follows.

Expression 3 Equation 4 Equation 5 Icr 'calculation About-73.8 -40.0 About -107.6 Image leakage current calculation value for R phase voltage -19.5 + j0.0 -19.5 + j33.8 -19.5-j33.8 Image leakage current calculation for S phase voltage 9.8 + j16.9 39.0 + j0.0 -19.5 + j33.8 Image leakage current calculation value for T phase voltage 9.8-j16.9 -19.5-j33.8 39.0 + j0.0

In Table 4, since the effective leakage current (Irs) of the S phase corresponds to the condition of Equation 4, the reactive leakage current (Icr) having the largest R phase corresponds to 40 mA. Increasing the reactive leakage current by 40mA will cause the reactive leakage current to equilibrate.

Next, since the effective leakage current Irs having the largest S phase corresponds to 39 mA, increasing the effective leakage current by 39 mA in R and T phases cancels the effective leakage current on the primary side of the current transformer 10. In this way, the effective leakage current will not be detected on the secondary side of the image transformer 10.

Next, C1, C2 and C3 of the compensation capacitance unit 311 in the compensation means 31 connected to the S and T phase voltage detection lines 13 and 14 in the leakage current compensator 30 (the embodiment of the present invention). Is composed of three capacitor elements for each phase, but is not limited to three.) In the current phase selection means 32 corresponding to the S and T phases, the phase voltages between the cable line 3 and the ground are calculated. When the contact switch corresponding to 40 mA of the invalid part compensation current Ics 'and Ict' among the contact switches sw1r, sw2r, and sw3r of the invalid part direction selection unit 321 is switched to the leakage current compensation winding 15 side, Corresponding capacitances C1, C2, C3 of the voltage detecting line 12, the compensating capacitance portion 311 in the compensating means 31, and the invalid partial direction selecting part in the current phase selecting means 32 ( 321 and the leakage current compensation winding 15 in the same direction as the image leakage current Io flowing between the actual cable line 3 and the earth to the primary side of the current transformer 10. That is, the reactive current compensation current Ic 'is increased from the transformer 1 side of the image current transformer 10 through the image current transformer 10 to the ground side, thereby balancing the reactive leakage current Ic with the image current transformer 10. An almost no reactive leakage current (Ic) component will not be detected on the secondary side of the circuit. Next, r1, r2, r3 of the compensating resistor section 312 in the leakage current compensator 30 (in each embodiment of the present invention), Three resistance elements constitute the insulation resistance 9 but are not limited to three.) Current phase selection means (32) corresponding to the R and T phases are calculated by calculating the phase voltage between the cable line (3) and the earth. Of the contact switches (sw4r, sw5s, sw6t) of the effective partial direction selector 322 in which the effective part compensation currents Irr 'and Irt' correspond to 39 mA, is switched to the leakage current compensation winding 15 side. And corresponding resistors r1, r2, r3 of the voltage detecting line 13 and the compensating resistor part 312 in the compensating means 31 and the electric field. The image leakage current flowing between the actual cable line 3 and the ground to the primary side of the current transformer 10 through the effective partial direction selection unit 322 and the leakage current compensation winding 15 in the phase selection means 32. In the same direction as Io, that is, the effective current leakage current Ir is balanced by increasing the effective compensation current Ir 'from the transformer 1 side of the image current transformer 10 to the ground side. On the secondary side of the video current transformer 10, an almost effective leakage current Ir component is not detected. Therefore, the reactive leakage current Ic and the effective leakage current Ir component are hardly detected on the secondary side of the image transformer 10, and the image leakage current Io component is formed on the secondary side of the image transformer 10. This is hardly detected.

Next, the reactive compensation current Ic 'through the leakage current compensation winding 15, that is, the reactive compensation currents Ics' and Ict 'of the S phase and the T phase in this example, and the effective compensation current Ir', In this example, the insulation detector having the secondary side of the image transformer 10 connected to the primary current windings of the image transformer 10 while the effective compensation currents Irr 'and Irt' of the R phase and the T phase are flowing. The image correction current Io 'is detected by the leakage current detecting means 22 through amplification and filtering, and the image correction current Io' detected by the leakage current detecting means 22 is a leakage current. The three-phase each phase is displayed on the display means 25 and in the voltage component conversion means 211 in the voltage component detection means 21 in the insulation detector 20 to which the voltage detection lines 12, 13, and 14 are connected. Converts a phase voltage into a constant voltage, and converts the phase voltage component of each phase of each of the three phases converted by the voltage component converting means 211 and the In the phase detection means 23 to which the image correction current Io 'detected by the snow current detection means 22 is inputted, the phase difference θr' and the S phase voltage component of the image correction current Io 'with respect to the R phase voltage component are input. The phase difference θs 'of the image correction current Io' with respect to the phase difference θt 'of the image correction current Io' with respect to the T phase voltage component is detected and displayed on the phase difference display means 25.

When it is confirmed that the phase difference θr ', θs', and θt' between the magnitude of the corrected image current Io 'and the image correction current Io' for the three-phase each phase voltage component are almost zero, R, The effective resistance compensation currents (Irr 'and Irt') corrected for T phase and the effective leakage current (Irs') of the S phase, in which the three-phase vector sum becomes zero, flows between the actual line 3 and the earth (9). This corresponds to the effective leakage current (Ir) flowing by), and since the reactive leakage current (Ic) component hardly flows on the primary side of the image transformer 10, the image transformer 10 has a very small effective leakage current ( Since it is induced on the secondary side of the image current transformer 10 as much as Ir), it is possible to detect the effective leakage current Ir flowing to the ground by the insulation resistance 9 which is directly related to the earth leakage with high sensitivity. The image which becomes the short circuit by being able to confirm the image which is the worst, the short circuit Investigating and acting on the leakage power supply intensively can save time in the leakage power supply investigation and action, and additionally, the information of the phase with the largest capacitance and the amount of reactive leakage current (Ic) You will also know. On the other hand, if θr 'θs' θt 'with the image correction current Io' becomes almost zero, the reactive compensation currents Ics 'and Ict' and the effective compensation currents Irr 'and Irt' It is preferable to repeat the operation performed in the above state in the state of flowing the leakage current compensation means 15 so that the image correction current Io 'is hardly detected on the secondary side of the image current transformer 10.

In the example described above, in the case where the effective leakage current Ir caused by the insulation resistance of one of the three phases or the reactive leakage current Ic caused by the capacitance flows large, the effective leakage current Ir or the reactive leakage current ( The image leakage current Io flowing between the actual cable line 3 and the ground by detecting and calculating the effective differential compensation current Ir 'or the reactive differential correction current Ic' for two other phases except for the phase where Ic is large. However, if the effective leakage current (Ir) due to the insulation resistance of two phases of three phases or the reactive leakage current (Ic) due to capacitance is large, effective leakage occurs. Detecting and calculating the effective portion correction current Ir 'or the reactive portion correction current Ic' for one phase having the smallest current Ir or the reactive portion leakage current Ic, between the actual line 3 and the ground Opposite the current flow direction of flowing image leakage current (Io) It is preferable to use a method of confirming that the image correction current (Io) is almost zero by flowing in the direction of the direction, or in the order of applying the correction current to the smallest phase first and then the correction current to the next small phase. Do.

(Sixth Embodiment)

Next, FIG. 11 and FIG. 14 and FIG. 16, which is a fifth embodiment of the insulation detector of the insulation detection system of the present invention, will be described as a sixth embodiment for explaining the insulation detection method and the leakage current compensator of the present invention.

The configuration of FIG. 11 is substantially the same as that of FIGS. 9 and 10 described above, but in FIG. 9, the fourth embodiment, voltage detection lines 12 and 13 connected to detect voltage components of three-phase respective phases between the cable line 3 and the earth. 14 is connected to the leakage current compensator 30 so that the capacitances C1, C2 and C3 in the compensation capacitance part 311 in the compensation means 31 and the compensation resistance portion in the compensation means 31 The load (4) of the image current transformer 10 is passed through the ineffective direction selection section 321 and the effective direction selection section 322 in the current phase selection means 32 through the resistors r1, r2, r3 in the 312. ) Is connected to the leakage current compensation winding 15 connected to the ground through the primary side of the current transformer 10 from the transformer 1 to the transformer 1 side, so that the current flow direction of the image correction current Io ' It is composed of the direction opposite to the flow direction of the image leakage current (Io) between the ground. In FIG. 10, the fifth embodiment, voltage detection lines 12, 13, and 14 connected to detect the voltage component of each of the three-phase respective phases between the cable line 3 and the ground are connected to the leakage current compensator 30 to compensate for the voltage. 31. Current phase selection through the capacitances C1, C2, C3 in the compensation capacitance section 311 and the resistors r1, r2, r3 in the compensation resistor section 312 in the compensation means 31. Through the invalid partial direction selecting section 321 and the effective partial selecting section 322 in the means 32, the image current transformer 10 is moved from the load 4 of the current transformer 10 to the transformer 1 side. It is connected to the leakage current compensation winding 15 connected to the ground through the current flow direction of the image correction current (Io ') is configured in the same direction as the flow direction of the image leakage current (Io) between the cable line 3 and the ground have. On the other hand, in FIG. 11, the sixth embodiment, voltage detection lines 12, 13, and 14 connected to detect the voltage component of each of the three-phase respective phases between the cable line 3 and the ground are connected to the leakage current compensator 30 for compensation. Current through the capacitances C1, C2, C3 in the compensation capacitance portion 311 in the means 31 and the resistors r1, r2, r3 in the compensation resistance portion 312 in the compensation means 31. The current flow direction of the image compensating current Io 'is controlled from the load 4 of the image current transformer 10 through the invalid partial direction selecting section 321 and the effective partial direction selecting section 322 in the phase selection means 32. Whether to flow through the primary side of the image transformer 10 to the transformer 1 side to ground or through the primary side of the image transformer 10 from the transformer 1 side of the image transformer 10 to the load 4 side. Can be selected to flow in the direction opposite to the image leakage current (Io) flowing between the cable line 3 and the ground or in the same direction Differs in that the configuration is connected to the primary side in which the leakage current compensation winding (15) through the current transformer of the image 10 through the direction selection means (33). That is, since it corresponds to the embodiment of the mixed form of the fourth embodiment and the fifth embodiment, a detailed description thereof will not be given below.

9 and 5, which is the fourth embodiment described above, and FIG. 11, which is the fifth embodiment, and FIG. 11, the secondary side connection of the transformer 1 is described as a wire connection. Although the connection configuration diagram of another embodiment is illustrated as shown in FIG. 10, the secondary side connection of the transformer 1 is changed to a delta connection, but the leakage current compensator used in FIGS. 30 can also be applied.

13 is an embodiment for explaining that the secondary side connection of the transformer 1 can also be used in the non-grounding method. 18 and 19 show an embodiment in which the voltage converting means of Figs. 16 and 17, which are the voltage component detecting means used in the fourth to sixth embodiments, of Figs. However, in FIG. 18, which is the first embodiment of the voltage converting means, there may be an embodiment in which capacitors Cv1 and Cv2 are configured in series using a capacitor instead of a resistor to use voltage components of each phase shown in Cv2. In FIG. 19, which is a second embodiment of the voltage converting means, the voltage can be converted even when the transformer TR is used without converting the voltage using the resistor or the capacitor. In FIG. 19, a capacitor may be used instead of the resistor Rv connected between the secondary side of the transformer TR and the ground, and the voltage of each three-phase phase between the secondary side of the transformer TR and the ground without using a resistor or a capacitor. There may also be embodiments of the configuration using the components. In addition, in the exemplary embodiment of the present invention, only one leakage current compensation winding 15 is used, but three leakage current compensation windings 15 may be used for each of the three phases, or the effective leakage current and the reactive leakage current may be adjusted. Two leakage current compensation windings 15 may be used to compensate, or two leakage current compensation windings 15 may be used to compensate for the effective leakage current and the reactive leakage current for each of the three phases. There may be an embodiment using the leakage current compensation winding 15. In addition, in the embodiment of the present invention, the current phase selecting means 32 and the effective portion direction selection section 321 and the effective portion for selecting whether to flow the reactive compensation current to the ground side or the leakage current compensation winding 15 side. Although it consists of an effective partial direction selecting section 322 for selecting whether to flow the compensation current to the ground side or the leakage current compensation winding 15 side, the invalid partial direction selecting section 321 and the effective partial direction selecting section ( There may be an embodiment that can serve two functions of 322. In addition, the reactive partial selector 321 and the effective partial selector 322 are configured such that only the selected capacitance or resistance is connected to the leakage current compensation winding 15 by connecting a capacitance or a resistor to the ground side at all times. Alternatively, the capacitance or resistance is connected to the always-leakage current compensation winding 15 side, so that only the selected capacitance or resistance is connected to the ground side, or the capacitance is connected to the always-ground side, and the resistance is always the leakage current compensation winding 15 It may be configured to be connected to the side), or in the case of being configured with a plurality of capacitances or resistors to be connected to the always-ground side and the leakage current compensation winding 15 side. In addition, although the embodiment of the present invention has been described with respect to the embodiment in which the installation position of the image current transformer 10 is installed in the middle of the electric wire path 3 which is intermediate between the transformer 1 and the load 4, the transformer 1 and There may be an embodiment provided in the middle of the ground line 5 of the ground (6), the connection position of the voltage detection lines (12, 13, 14) is connected to the front end of the image transformer 10, that is, the transformer 1 side direction Although the embodiment has been described, there may be an embodiment connected to the rear end of the image transformer 10, that is, the load 4 side. In addition, in the embodiment of the present invention, the voltage component converting means 211 for detecting the voltage component is composed of an internal configuration of the insulation detector 20, but the portion having the function of the voltage component converting means 211 has the insulation detector 20. There may also be an embodiment configured outside of the. There may be an embodiment in which some functions of the leakage current detecting means 22 for detecting the image leakage current are configured outside the insulation detector 20, and instead of the phase voltage detected by the voltage detecting lines 12, 13, and 14, respectively. There may be an embodiment of detecting the line voltage in the above, and there may also be an embodiment in which a voltage component of only one phase of the three phases is used and phase shifted by 120 degrees to convert the three phase voltage components. It is obvious that the person skilled in the art related to the present invention can be easily applied without departing from the scope of the present invention.

The present invention provides an insulation resistance that is insulated from an electric line including a load even when a large amount of reactive leakage current (Ic) flows due to the capacitance flowing between the electric wire and the ground in an unbalanced state of capacitance existing between the earth of a three-phase electric wire including a load. Effective leakage current can be accurately detected with high sensitivity, and even the information of the worst phase can be known.

In addition, the present invention does not generate an image leakage current between the wire and the ground in the leakage current compensator for canceling the reactive leakage current flowing through the image current transformer, so that it does not affect other insulation detectors and thus prevents malfunction of other insulation detectors. It can be effective.

Claims (10)

A voltage detection line for detecting an AC voltage of the three-phase wire; Voltage component detecting means for detecting a voltage component between the earths of each of the three phases inputted by the voltage detecting line; An image current transformer for detecting a leakage current component flowing between the three-phase wire path and the ground; Leakage current detection means for amplifying and filtering the leakage current component detected at the secondary side of the image current transformer; Phase difference detecting means for detecting a phase difference between the voltage component detected by the voltage component detecting means and the leakage current component output from the leakage current detecting means; Impedance of the three-phase alternating current between the three-phase AC voltage component inputted by the voltage detection line and the earth ground is made almost equal so that no additional leakage current flows in the actual cable line, and no leakage is caused by the capacitance of the actual cable line. In the insulation detection method of the electric wire path detecting the insulation state of the three-phase electric wire by providing a leakage current compensator for making a compensation leakage current to compensate the current to flow to the image current transformer or earth ground, By using the leakage current value output from the leakage current detecting means and the phase difference of the three-phase each phase detected by the phase difference detecting means, the value of the reactive divided leakage current due to the capacitance detected at the secondary side of the image current transformer is almost The leakage current flowing through the image current transformer to the image current transformer or the leakage current compensation winding formed by the primary winding separately configured by the compensation capacitance by the capacitance operated by the leakage current compensator. Causing it to flow in the opposite or same direction as the one; And detecting an insulation state of the cable line by detecting a leakage current component detected at a secondary side of the image current transformer. A voltage detection line for detecting an AC voltage of the three-phase wire; Voltage component detecting means for detecting a voltage component between the earths of each of the three phases inputted by the voltage detecting line; An image current transformer for detecting a leakage current component flowing between the three-phase wire path and the ground; Leakage current detection means for amplifying and filtering the leakage current component detected at the secondary side of the image current transformer; Phase difference detecting means for detecting a phase difference between the voltage component detected by the voltage component detecting means and the leakage current component output from the leakage current detecting means; Impedance of the three-phase alternating current between the three-phase AC voltage component inputted by the voltage detection line and the earth ground is made almost equal so that no additional leakage current flows in the actual cable line, and no leakage is caused by the capacitance of the actual cable line. Insulation detection method for a wire path which detects the insulation state of a three-phase wire path by providing a leakage current compensator for making a compensatory leakage current for compensating an effective leakage current by current or insulation resistance and flowing it to the image current transformer or earth ground. To By using the leakage current value output from the leakage current detecting means and the phase difference of each of the three phases detected by the phase difference detecting means, the leakage current value due to capacitance or insulation resistance detected at the secondary side of the image current transformer is Leakage current compensation winding consisting of a test wire of a current transformer or a primary winding configured separately so that the leakage current for compensation caused by the capacitance or resistance manipulated by the leakage current compensator is opposite to the leakage current flowing through the image current transformer. Or flowing in the same direction; And detecting the insulation state of the cable line by using a compensation leakage current value flowing by the capacitance or the resistance operated by the leakage current compensator. In the insulation detection system of an electric wire path which detects the insulation state of a three-phase electric wire path, An image current transformer for detecting a leakage current component flowing between the three-phase wire path and the ground; Leakage current detection means for amplifying and filtering the leakage current component detected by the image current transformer; Leakage current display means for displaying an output value of the leakage current detection means; A voltage detection line for detecting an AC voltage of the three-phase wire; Converts the voltage component between the three phases of each phase input by the voltage detection line to a certain magnitude and selects the voltage component of one of the three phases or detects the voltage components of all three phases of each phase input by the voltage detection line. Voltage component detecting means for performing; Phase difference detecting means for detecting a phase difference between the voltage component detected by the voltage component detecting means and the leakage current component output from the leakage current detecting means; Phase difference display means for displaying an output value of the phase difference detection means; Impedance of the three-phase AC voltage component inputted by the voltage detection line and the three-phase each phase between the earth ground is made almost the same so that no additional leakage current flows in the actual line and the leakage current due to the capacitance of the actual line And a leakage current compensator for making a compensatory leak current for compensating and flowing it to the image current transformer or ground. In the insulation detection system of an electric wire path which detects the insulation state of a three-phase electric wire path, An image current transformer for detecting a leakage current component flowing between the three-phase wire path and the ground; Leakage current detection means for amplifying and filtering the leakage current component detected by the image current transformer; Leakage current display means for displaying an output value of the leakage current detection means; A voltage detection line for detecting an AC voltage of the three-phase wire; Converts the voltage component between the three phases of each phase input by the voltage detection line to a certain magnitude and selects the voltage component of one of the three phases or detects the voltage components of all three phases of each phase input by the voltage detection line. Voltage component detecting means for performing; Phase difference detecting means for detecting a phase difference between the voltage component detected by the voltage component detecting means and the leakage current component output from the leakage current detecting means; Phase difference display means for displaying an output value of the phase difference detection means; The three-phase AC voltage component inputted by the voltage detecting line and the grounding of the three-phase each phase are configured to be substantially the same, so that no additional leakage current flows in the actual line, and the capacitance and insulation resistance of the actual line And a leakage current compensator for making a compensatory leakage current capable of compensating for leakage current and flowing it to the image current transformer or ground. 5. The apparatus as claimed in claim 3 or 4, wherein the voltage component detecting means includes: voltage component converting means for detecting a voltage component between an electric wire path and a ground and converting the voltage component into a predetermined magnitude; And a voltage phase selection means for reading the voltage of one phase of the three phase voltage components converted by said voltage component conversion means. In the leakage current compensator used for the insulation detection device for detecting the leakage current of the three-phase wire, An image current transformer for detecting a leakage current component flowing between the three-phase wire path and the ground; Leakage current detection means for amplifying and filtering the leakage current component detected by the image current transformer; Leakage current display means for displaying an output value of the leakage current detection means; A voltage detection line for detecting an AC voltage of the three-phase wire; Compensation means connected to the voltage detection line, configured to make the impedance of each of the three phases between the detected three-phase commercial AC voltage component and the earth ground almost equal, and for making a compensation leakage current; Leakage current compensation winding means for flowing a compensatory leakage current through the image current transformer to earth ground; Current phase selection for selecting whether to flow the compensatory leakage current flowing through the compensating means to the earth ground for each of the three phases or through the leak current compensation winding means by the commercial AC voltage of the voltage component detecting means. Way; The leakage current compensator, characterized in that the direction of the compensation leakage current flowing through the current phase selection means is configured to be in the opposite direction or the same direction as the direction of the leakage current flowing between the wire and the ground including the actual load. In the leakage current compensator used for the insulation detection device for detecting the leakage current of the three-phase wire, An image current transformer for detecting a leakage current component flowing between the three-phase wire path and the ground; Leakage current detection means for amplifying and filtering the leakage current component detected by the image current transformer; Leakage current display means for displaying an output value of the leakage current detection means; A voltage detection line for detecting an AC voltage of the three-phase wire; Compensation means connected to the voltage detection line, configured to make the impedance of each of the three phases between the detected three-phase commercial AC voltage component and the earth ground almost equal, and for making a compensation leakage current; Leakage current compensation winding means for flowing a compensatory leakage current through the image current transformer to earth ground; Current phase selection for selecting whether to flow the compensatory leakage current flowing through the compensating means to the earth ground for each of the three phases or through the leak current compensation winding means by the commercial AC voltage of the voltage component detecting means. Way; And a ground direction selection means for selecting whether to flow the leakage current for compensation flowing through the current phase selection means in the same direction as the direction of the leakage current flowing between the cable line and the earth including the actual load or in the opposite direction. Leakage current compensation, characterized in that configured. 8. The leakage current compensator of claim 6 or 7, wherein the compensating means comprises one or more capacitances or resistors for each phase. 8. The compensation capacitor according to claim 6 or 7, wherein the compensation means comprises: a compensation capacitance unit comprising one or more capacitances for compensating the reactive leakage current by the capacitance for each phase; A leakage current compensator for a wire line, comprising: a compensating resistor part consisting of one or more resistors for compensating an effective leakage current due to an insulation resistance. 8. The apparatus according to claim 6 or 7, wherein the current phase selection means comprises: an invalid portion direction selection section for selecting whether to flow an invalid portion compensation current to the ground side or a leakage current compensation winding side; A leakage current compensator for a wire passage comprising an effective division direction selection section for selecting whether to flow an effective compensation current to the ground side or a leakage current compensation winding side.

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