KR20080015648A - Insulation detecting system - Google Patents

Abstract

An insulation detecting system is provided to remotely control insulation resistance for voltage of a commercial AC frequency between a power line and the ground. An analog/digital converting unit(61) converts an analog value into a digital value. A digital/analog converting unit(51a,51b,51c) converts the digital value into the analog value. An analog multiplying unit(52a,52b,52c) multiplies an analog component. A setting unit(63) sets and inputs various data. A display unit(64) displays the various data or alarms. An operation control unit(62) has an operation function. A memory unit(66) stores the various data. A voltage detecting device detects a voltage component of a power line to accurately detect active leakage current. A voltage detecting unit(31a,31b,31c) converts the voltage component into a predetermined voltage size. A voltage filter unit(32a,32b,32c) extracts the voltage component of a commercial frequency component from the voltage component. A 90 degree phase shifting unit(33a,33b,33c) shifts a phase of voltage of the commercial frequency component by 90 degrees. A zero phase current transformer(10) detects zero leakage current flowing between the power line and the ground. A current/voltage converting unit(41) converts a current value of the zero phase leakage current into a voltage value. An amplifying unit(42) amplifies the zero phase leakage current. A current filter unit(43) extracts a zero phase leakage current component of the commercial frequency component through the voltage filter unit. A synchronous detecting unit(44) synchronously detects the zero phase leakage current component of the commercial frequency component, the voltage component of the commercial frequency component, and the 90 degree shifted voltage component. A reactive current compensating winding has an auxiliary winding function. A compensating filter unit(53a,53b,53c) flows current to the reactive current compensating winding of the zero phase current transformer.

Description

Insulation Detecting System

1 is an explanatory diagram of an embodiment of an insulation monitoring system in a conventional live state;

2 is an explanatory diagram of still another embodiment of an insulation monitoring system in a conventional live state;

3 is an explanatory diagram of the connection connection of the first embodiment of the insulation monitoring system in the three-phase wire path of the present invention;

4 is an explanatory diagram of the connection and connection of the second embodiment of the insulation monitoring system in the three-phase electric wire of the present invention.

5 is an explanatory diagram of a connection connection of a third embodiment of the insulation monitoring system in the three-phase electric wire of the present invention.

6 is an explanatory view of the connection and connection of the fourth embodiment of the insulation monitoring system in the three-phase electric wire of the present invention.

7 is an explanatory view of the connection and connection of the fifth embodiment of the insulation monitoring system in the three-phase wire path of the present invention.

8 is an explanatory view of the connection and connection of the sixth embodiment of the insulation monitoring system in the three-phase wire path of the present invention.

9 is an explanatory view of the connection and connection of the seventh embodiment of the insulation monitoring system in the three-phase electric wire of the present invention.

10 is an explanatory view of the connection and connection of the eighth embodiment of the insulation monitoring system in the three-phase electric wire of the present invention.

FIG. 11 is an internal detailed explanation view of a first embodiment of the insulation monitoring apparatus in the three-phase electric wire of the present invention. FIG.

12 is an internal detailed view of a second embodiment of the insulation monitoring apparatus in the three-phase electric wire of the present invention.

FIG. 13 is an internal detailed view of a third embodiment of an insulation monitoring apparatus in a three-phase wire path of the present invention. FIG.

14 is an internal detailed diagram of a fourth embodiment of the insulation monitoring apparatus in the three-phase electric wire of the present invention.

Fig. 15 is an internal detailed explanation view of a fifth embodiment of the insulation monitoring apparatus in the three-phase electric wire of the present invention.

16 is an internal detailed view of a sixth embodiment of an insulation monitoring apparatus in a three-phase wire path of the present invention.

17 is an internal detailed view of a seventh embodiment of an insulation monitoring apparatus in a three-phase wire path of the present invention.

18 is a representative operation flow used in the embodiment of the insulation monitoring device for a three-phase electric wire of the present invention

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

1: transformer 2: switchgear

3: line (line) 4: load equipment

5: ground wire 6: ground for transformers

7: Ground 8: Line capacitance

9: earth insulation resistance of cable line 10: current transformer

12: insulation monitoring device

21, 21a, 21b, 21c: reactive current compensation winding

22a, 22b, 22c: voltage detection means

31,31a, 31b, 31c: voltage detector 32,32a, 32b, 32c: voltage filter

33a, 33b, 33c: 90 degrees or more 34: 120 degrees or more

35: 240 degrees or more

41: current / voltage converter 42: amplifier

43: current filter unit 44: synchronous detector

51, 51a, 51b.51c: digital / analog converter

52, 52a, 52b, 52c: Analog multiplication part

53, 53a, 53b, 53c: compensation filter unit

54, 54a, 54b, 54c: Zero cross section

55,55a, 55b, 55c: Digital multiplication part

56,56a, 56b, 56c: waveform shaping section

61: analog / digital conversion unit 62: operation control unit

63: setting unit 64: display unit

65: output unit 66: storage unit

The present invention is not directly related to the leakage current in the live state at the wire line and the load input terminal in the live state, without directly discharging the insulation state of the three-phase line, regardless of the magnitude of the reactive leakage current of the component of the capacitance. In the insulation monitoring system that detects the active component leakage current or insulation resistance value of the relevant insulation resistance component in a live state,

When the leakage current of the reactive component flowing through the capacitance is very large due to the AC commercial voltage, and the leakage current of the effective component flowing due to the insulation resistance is very small, the reactive component detected by the image current transformer detecting the leakage current is large. In order to eliminate the influence that the leakage current value has a significant influence on the detection error of the small leakage current value of the effective portion, the commercial AC voltage component of the three-phase cable is detected, and the leakage current corresponding to the commercial AC frequency (60 Hz or 50 Hz) component. Is detected through the current transformer, and the detected leakage current is taken out as the leakage current corresponding to the 90 degree phase difference of the detected commercial AC voltage. After the reverse current flows to the current transformer to allow the leakage current corresponding to the invalid component to be erased, Leakage current component corresponding to the minute only is to ensure that detected by the image current transformer according to the insulation monitoring system for monitoring the leakage current of the effective minute image current transformer accurately detect and display the available minute leakage current value corresponding to an insulation resistance value and the resistance component.

It also detects the leakage current (Io) flowing between the cable line and the ground before removing the invalid leakage current, and uses it as the comparison data.Also, it performs an alarm function if the detected data is larger than the preset leakage current alarm set value. can do.

Conventionally, a device that detects and monitors an insulation state of a three-phase wire path in a live state, that is, a short circuit detection device, as shown in FIG. 1 is located in the middle of the wire path 3 between the transformer 1 and the load 4 or in the transformer 1. The reactive current leakage current (Ioc) leaked by the capacitance (8) flowing between the cable line (3) and the earth (7) by installing the current transformer (10) in the middle of the ground wire (5) connected between the neutral point and the earth And the image leakage current Io = Ior + Ioc corresponding to the vector sum of the effective leakage current Ior by the insulation resistance 9 are detected by the image current transformer 10, and the image current transformer 10 described above. If the leakage current (Io) detected by the amplification and filtering in the insulation monitoring device 12 is greater than a preset value, an insulation monitoring system such as an earth leakage alarm or a leakage current meter displaying an alarm or displaying the detected leakage current value is generally used. Has been used. Similar devices include an earth leakage relay, an earth leakage circuit breaker, a clamp meter, a ground fault detector, and the like. In the present invention, the "electric line" or the "electric line" includes not only a low voltage line including a load but also a high voltage line. Means.

The insulation monitoring system which detects the image leakage current (Io) described above and monitors the insulation state is a case where the effective leakage current (Ior) and the line are long due to the insulation resistance 9 existing between the cable line 3 and the ground. Is detected by the vector sum of the reactive leakage current (Ioc) caused by the capacitance 8 generated by the capacitance 8 and the noise filter inserted into the input terminal of the load facility. Even if the capacitance is very good, the reactive leakage current (Ioc) caused by the capacitance component is also increased because the capacitance is very large, and there has been a problem that the insulation state is poorly measured, i.e., it is detected and detected that a short circuit or an uninterrupted occurrence has occurred.

Due to this problem, foreign countries use Japanese Utility Model Publication No. Hei 7-29477 (Insulating Leakage Current Measuring Device) to detect an effective leakage current (Ior) corresponding to an insulation resistance component caused by an insulation state in a live state. . The device is briefly described as a three-phase cable line but has the configuration as shown in FIG. 2 and detects the leakage current Io flowing through the ground line 5 of the transformer 1 once grounded by the image current transformer 10. The reference voltage (Vrs) corresponding to the phase voltage between the phase grounded and the non-grounded phase is measured through the reference voltage input line connected to the charging unit separately in the insulation monitoring device 12 on the wire path 3, and the leakage current The phase difference θ is obtained from Io and Vrs, and the effective leakage current value Ior corresponding to the resistance component is calculated from the phase difference θ and the leakage current Io. This method has various problems, but when the insulation resistance (9) component between the cable line (3) and the ground is very small and the capacitance (8) component is very large, the current leaked to the ground by the commercial AC voltage (Io). Since Ioc >> Ior, the leakage current detected by the image current transformer 10 is due to the reactive leakage current (Ioc) due to the very large capacitance (8). The measurement sensitivity of Ior) is not accurate because the magnetic field characteristics of the current transformer in the current transformer 10 are deteriorated and the leakage current (Io), which is widely used in the prior art, is not displayed. Due to the large (Ioc) component, it is inconvenient to provide various types of information to the leakage manager, such as being unable to compare whether the image leakage current (Ioc) is largely detected. In addition, Japanese Utility Model Publication No. 58-180478 (line-to-point capacitive compensator), which is applied to the effect of the capacitance (8) component, corresponds to the capacitance (8) having a value corresponding to the capacitance existing between the grounds. The method of eliminating the leakage current of the reactive component flowing through the image transformer 10 is operated by operating a variable capacitance separately installed in the insulation monitoring device so that the leakage current of the reactive component flows in the opposite direction to the image transformer 10. . However, this method has been inconvenient for the measurer to manipulate the variable capacitance.

Therefore, even when the capacitance 8 component existing between the grounds is very large, that is, the reactive leakage current Ioc is very large, the insulation resistance 9 component is very large, that is, the effective leakage current Ior is very small. There has been a need for an insulation monitoring system capable of accurately detecting the effective leakage current (Ior).

In addition, smooth wire management is provided by providing detection data necessary for various leakage managers including the image leakage current Io and the invalid leakage current Ioc before the removal of the reactive leakage current Ioc detected by the conventional method. Insulation monitoring systems have been required.

Therefore, in the present invention, the insulation resistance 9 which is directly related to the leakage current even in a state where the capacitance (8) component existing between the grounds which is not directly related to the above-mentioned leakage current is very large, that is, the reactive leakage current (Ioc) is very large. When the component is very large, that is, the effective leakage current (Ior) is accurately detected, the effective leakage current (Ior) is accurately detected, and the image leakage current (Io) and the invalid of the commercial frequency component flowing between the actual line 3 and the ground An object of the present invention is to provide an insulation monitoring system capable of detecting and displaying minute leakage current (Ioc).

In addition, the object of the present invention is to provide an insulation monitoring system that can remotely control the display, alarm alarm output and input / output by calculating the insulation resistance (9) against the voltage of the commercial alternating frequency between the cable line (3) and the earth.

Still other objects of the present invention will become apparent from the following detailed description and the accompanying drawings.

Insulation monitoring system of claim 1 for detecting the insulation state of the three-phase wire in the live state of the present invention for achieving the above object,

An analog / digital converter having a function of converting an analog value into a digital value; A digital / analog converter having a function of converting a digital value into an analog value; An analog multiplication unit having a function of multiplying (or mixing) analog components; A setting unit having a function of setting and inputting various data by using a kind of component such as a keypad or a switch; A display unit capable of displaying various data or displaying alarms; An operation control unit for reading and outputting various data and having an operation function; A storage unit having a function of storing various data;

Voltage detecting means for detecting a voltage component of the cable line to accurately detect and monitor an effective leakage current of the insulation resistance component existing between the earth even if the capacitance component existing between the wire path and the earth is very large; A voltage detector for converting the voltage component detected by the voltage detector into a predetermined voltage; A voltage filter unit for extracting a voltage component of a commercial frequency component among the voltage components converted through the voltage detector; 90 degrees or more for shifting the phase of the voltage of the commercial frequency component extracted through the voltage filter unit by 90 degrees; An image current transformer for detecting an image leakage current flowing between an electric line and a ground; A current / voltage converter for converting the current value of the image leakage current component detected by the secondary side of the image current transformer into a voltage value; An amplifier for amplifying the image leakage current component converted into a voltage component through the current / voltage converter; A current filter unit for extracting commercial frequency components among the image leakage current components amplified by the amplifying unit; Phase synchronizing the video leakage current component of the commercial frequency component extracted through the current filter unit with the voltage component of the commercial frequency component extracted through the voltage filter unit and the 90-degree shift voltage component converted in the above 90 degree portion. A synchronization detector for detecting; A reactive current compensation winding having a function of an auxiliary winding by being separately provided with a test cable or on a primary side of the image current transformer; And a compensation filter unit having a function of extracting a commercial frequency component and flowing a current to the reactive current compensation winding of the image current transformer.

Insulation monitoring system of claim 2 for detecting the insulation state of the three-phase wire in the live state of the present invention for achieving the above object,

An analog / digital converter having a function of converting an analog value into a digital value; A zero cross section having a function of converting an AC component into a digital component by comparing magnitudes at zero points; A digital multiplier having a function of multiplying (or mixing) two digital components; A waveform shaping unit having a function of converting a digital value into an analog value and shaping a waveform; A setting unit having a function of setting and inputting various data by using a kind of component such as a keypad or a switch; A display unit capable of displaying various data or displaying alarms; An operation control unit for reading and outputting various data and having an operation function; A storage unit having a function of storing various data;

Voltage detecting means for detecting a voltage component of the cable line to accurately detect and monitor an effective leakage current of the insulation resistance component existing between the earth even if the capacitance component existing between the wire path and the earth is very large; A voltage detector for converting the voltage component detected by the voltage detector into a predetermined voltage; A voltage filter unit for extracting a voltage component of a commercial frequency component among the voltage components converted through the voltage detector; 90 degrees or more for shifting the phase of the voltage of the commercial frequency component extracted through the voltage filter unit by 90 degrees; An image current transformer for detecting an image leakage current flowing between an electric line and a ground; A current / voltage converter for converting the current value of the image leakage current component detected by the secondary side of the image current transformer into a voltage value; An amplifier for amplifying the image leakage current component converted into a voltage component through the current / voltage converter; A current filter unit for extracting commercial frequency components among the image leakage current components amplified by the amplifying unit; Phase synchronizing the video leakage current component of the commercial frequency component extracted through the current filter unit with the voltage component of the commercial frequency component extracted through the voltage filter unit and the 90-degree shift voltage component converted in the above 90 degree portion. A synchronization detector for detecting; A reactive current compensation winding having a function of an auxiliary winding by being separately installed on a test line of the image current transformer; And a compensation filter unit having a function of extracting a commercial frequency component and flowing a current to the reactive current compensation winding of the image current transformer.

Insulation monitoring system of claim 3 for detecting the insulation state of the three-phase wire in the live state of the present invention for achieving the above object,

An analog / digital converter having a function of converting an analog value into a digital value; A digital / analog converter having a function of converting a digital value into an analog value; An analog multiplication unit having a function of multiplying (or mixing) two analog components; A setting unit having a function of setting and inputting various data by using a kind of component such as a keypad or a switch; A display unit capable of displaying various data or displaying alarms; An operation control unit for reading and outputting various data and having an operation function; A storage unit having a function of storing various data;

Voltage detecting means for detecting a voltage component of the cable line to accurately detect and monitor an effective leakage current of the insulation resistance component existing between the earth even if the capacitance component existing between the wire path and the earth is very large; A voltage detector for converting the voltage component detected by the voltage detector into a predetermined voltage; A voltage filter unit for extracting a voltage component of a commercial frequency component among the voltage components converted through the voltage detector; 120 degrees or more for shifting the phase of the voltage of the commercial frequency component extracted through the voltage filter unit by 120 degrees; 240 degrees or more for shifting 240 degrees; 90 degrees or more for shifting the voltage phase of the voltage filter unit 120 degrees or more and 240 degrees or more by 90 degrees; An image current transformer for detecting an image leakage current flowing between an electric line and a ground; A current / voltage converter for converting the current value of the image leakage current component detected by the secondary side of the image current transformer into a voltage value; An amplifier for amplifying the image leakage current component converted into a voltage component through the current / voltage converter; A current filter unit for extracting commercial frequency components among the image leakage current components amplified by the amplifying unit; The image leakage current component of the commercial frequency component extracted through the current filter unit is converted from the voltage component of the commercial frequency component extracted through the voltage filter unit and 120 degrees or more and 240 degrees or more and 90 degrees or more. A synchronous detector for phase-synchronizing the 90 degree shift voltage component; A reactive current compensation winding having a function of an auxiliary winding by being separately installed on a test line of the image current transformer; And a compensation filter unit having a function of extracting a commercial frequency component and flowing a current to the reactive current compensation winding of the image current transformer.

Insulation monitoring system of claim 4 for detecting the insulation state of the three-phase wire in the live state of the present invention for achieving the above object,

An analog / digital converter having a function of converting an analog value into a digital value and a digital / analog converter having a function of converting a digital value into an analog value; An analog multiplication unit having a function of multiplying (or mixing) two analog components; A setting unit having a function of setting and inputting various data by using a kind of component such as a keypad or a switch; A display unit capable of displaying various data or displaying alarms; An operation control unit for reading and outputting various data and having an operation function; A storage unit having a function of storing various data;

Voltage detecting means for detecting a voltage component of the cable line to accurately detect and monitor an effective leakage current of the insulation resistance component existing between the earth even if the capacitance component existing between the wire path and the earth is very large; A voltage detector for converting the voltage component detected by the voltage detector into a predetermined voltage; A voltage filter unit for extracting a voltage component of a commercial frequency component among the voltage components converted through the voltage detector; 120 degrees or more for shifting the phase of the voltage of the commercial frequency component extracted through the voltage filter unit by 120 degrees; 90 degrees or more for shifting the voltage phase of the voltage filter unit and the 120 degrees or more by 90 degrees; An image current transformer for detecting an image leakage current flowing between an electric line and a ground; A current / voltage converter for converting the current value of the image leakage current component detected by the secondary side of the image current transformer into a voltage value; An amplifier for amplifying the image leakage current component converted into a voltage component through the current / voltage converter; A current filter unit for extracting commercial frequency components among the image leakage current components amplified by the amplifying unit; The image leakage current component of the commercial frequency component extracted through the current filter unit and the voltage component of the commercial frequency component extracted through the voltage filter unit and 120 degrees or more and the 90 degree shift voltage converted from the 90 degrees or more. A synchronous detection section for phase synchronous detection of components; A reactive current compensation winding having a function of an auxiliary winding by being separately installed on a test line of the image current transformer; And a compensation filter unit having a function of extracting a commercial frequency component and flowing a current to the reactive current compensation winding of the image current transformer.

In order to achieve the above object, the insulation monitoring system of claim 5 which detects the insulation state of the three-phase line in the live state of the present invention has a leakage current value compared with the alarm set value set in the setting unit or the alarm set value stored in the storage unit. If it is larger than the alarm set value or the insulation resistance value is smaller than the alarm set value, the alarm can be displayed on the outside by means such as buzzer, LED, relay in the display.

In addition, the insulation monitoring system of the present invention preferably further includes an input / output unit for telecommunication and control.

Hereinafter, the insulation monitoring system of the present invention will be described with reference to the accompanying drawings.

3 to 10 are examples in which the insulation monitoring system of the embodiment is installed in the three-phase wire path of the present invention, and FIGS. 11 to 17 are insulation monitoring devices 12 used in the three-phase wire path of FIGS. 3 to 10. The detailed embodiment of the inside). FIG. 18 is an exemplary flowchart illustrating an operation of the insulation monitoring apparatus of FIGS. 11 to 17.

3, 11, and 18, which are embodiments in the three-phase wire path, will be described first.

In FIG. 3, 1 is a transformer for converting to power through the switch 2 to the electric wire path (3). 5 is a ground wire for connecting to ground 6 for the safety of transformer 1. In general, the grounding of the transformer is generally conducted by two types of grounding, the load side is implemented by three kinds of grounding, and in the future, there is a high possibility of changing to common ground without distinguishing two or three kinds of grounding. On the other hand, in the state that power is supplied to the load 4 through the switchgear 2 and the wire path 3, the insulation resistance 9 and the capacitance 8 between the wire path 3 including the load 4 and the ground ) Exists. The insulation resistance 9 is directly related to the insulation state of the line 3 and the load 4, and the insulation resistance 9 includes the voltage component between the line 3 and the ground and the leakage current in phase, that is, the effective portion. The leakage current (Ior) flows, and the capacitance (8) indicates the capacitance component such as the noise filter at the load input terminal and the capacitance component existing between the cable and the ground, but is not directly related to the insulation state, that is, the insulation state. In the capacitance 8, the voltage component between the cable line 3 and the ground and the leakage current of the 90 degree phase difference, that is, the reactive leakage current Ioc flow. 10 is a leakage current detection means such as an image current transformer installed to detect leakage current components, ie, image leakage currents (Io = Ior + Ioc) flowing between the earths of the wires 3, and the primary side passes the wires to be monitored. The secondary side outputs a leakage current component that is proportional to the number of turns of the primary and secondary winding leakage components. When the insulation state of the three-phase cable line is monitored, the video current transformer 10 has a direction opposite to the leakage current flowing between the cable line 3 and the ground so that the reactive leakage current caused by the capacitance component is detected to be below a predetermined value. In order to flow to a separate auxiliary winding may be installed as a conductor on the primary side, or a plurality of separate tertiary windings may be used, or a winding may be used for testing the current transformer 10.

12 is an insulation monitoring device for monitoring an insulation state, which is an insulation state between the cable line 3 and the ground.

Insulation resistance that is directly related to a short circuit between the cable line 3 and the ground due to the insulation state of the wire line 3 or the load 4 in a state where electric power is supplied to the wire line 3 through the transformer 1 9) The effective leakage current (Ior) by 9) and the reactive leakage current (Ioc) due to the capacitance (8) not directly related to the short circuit cause the load-side type 3 ground (7) and the transformer-side type 2 ground (6). Leakage current (Io) flows through it. The leakage current Io is detected by the video current transformer 10 that detects the leakage current as a vector sum component of the effective leakage current Ior and the reactive leakage current Ioc and is input to the insulation monitoring device 12.

Then, voltage detection means 22a, 22b, 22c for detecting the voltage component of the cable line 3 to distinguish between the effective leakage current Ior and the reactive leakage current Ioc from the leakage current Io. Is applied to the insulation monitoring device 12.

First, FIGS. 11 and 18, which are the first embodiment of the insulation monitoring device 12, will be described in detail.

For example, various data used in the insulation monitoring device 12 as components such as a keypad or a switch in the main flow stored in the storage unit 66 inside the insulation monitoring device 12 as in the exemplary embodiment of FIG. When a plurality of insulation monitoring devices 12 are provided, data such as the number address, alarm set value, frequency, phase voltage of the line 3, and amplification rate for each component are provided for each insulation monitoring device 12. Various data setting flows 100 in the setting unit 63 having a settable function are executed, and then stored in advance in the various data or storage units 66 set by the setting unit 63 above. The operation of various data read flows 110 to read various data inputted through the external I / O unit 65 from the data or an external remote location is executed, and then Vr2, Vs2, Vt2, Vr3, Vs3, Vt3 read & store flows ( 120) is executed, the insulation monitoring system of FIGS. The leakage current Io detected by the leakage current detecting means 10 and the voltage component detected by the voltage detecting means 22a, 22b, 22c of the embodiment are input to the insulation monitoring device 12. The voltage components detected by the voltage detecting means 22a, 22b, and 22c are devide to voltages usable by the insulation monitoring device 12 using resistors, capacitors, or transformers in the voltage detecting parts 31a, 31b, and 31c, and Vr1. The Vr1, Vs1, and Vt1 voltage components are output in the values of Vs1, Vt1, and are commonly used in the voltage filter units 32a, 32b, and 32c because the components of the commercial frequency components, the commercial frequency components, and the noise components of other components are mixed. Only the voltage components Vr2, Vs2 and Vt2 of the frequency component are taken out. 90 degrees or more (33a, 33b, 33c) for shifting the phase of the voltage components (Vr2, Vs2, Vt2) of the commercial frequency components taken out from the voltage filter units (32a, 32b, 32c) by 90 degrees. In the 90 degree or more portions 33a, 33b, and 33c, the phases of the voltage components Vr2, Vs2, and Vt2 of the commercial frequency components are converted to 90 degree shift voltage components Vr3, Vs3, and Vt3 shifted by 90 degrees. The voltage components (Vr2, Vs2, Vt2) and the 90-degree shift voltage components (Vr3, Vs3, Vt3) of the commercial frequency components extracted from the voltage filter units 32a, 32b, and 32c are converted into analog values as digital values. The analog / digital converter 61 converts the Vr2, Vs2, Vt2 and Vr3, Vs3, Vt3 values into digital values, and the arithmetic and control unit 62 The data of Vr2, Vs2, Vt2, Vr3, Vs3, and Vt3 is stored in the storage unit 66 via the &quot;

 Next, when the Io1 read & store flow 130 is executed, as described above, the image leakage current component Io detected through the image current transformer 10 converts the current into a voltage. The leakage current component converted into a voltage component in the amplifier 42 and amplified by the amplifier 42 extracts only the leakage current Io1 of the commercial frequency component from the current filter unit 43, and sends it to the analog / digital converter 61 described above. It is output and stored in the memory | storage part 66 via the arithmetic and control part 62 mentioned above.

Next, when Iocr1, Iorr1, Iocs1, Iors1, Ioct1, Iort1 read & store flow 134 is executed, the leakage current (Io1) component of the commercial frequency component taken out from the current filter unit 43 and the above voltage fill Voltage components Vr2, Vs2, and Vt2 of the commercial frequency components extracted from the terminators 32a, 32b, and 32c, and 90 degree shift voltage components Vr3, Vs3, Vt3) Six components are input to the synchronous detection section 44 for synchronous detection of phase. In the synchronous detector 44, the leakage of the component having the same phase as the 90-degree shift voltage component Vr3 corresponding to the R phase among the leakage current Io1 components of the commercial frequency component under the control of the operational controller 62. The leakage current Iocr1 component of the current, i.e., the reactive leakage current Ioc, flowing in the capacitance 8 is taken out and output to the analog / digital converter 61, through the arithmetic and control unit 62. The leakage current Io1 component of the commercial frequency component described above is stored in the storage unit 66 and is controlled by the arithmetic and control unit 62, and the leakage current of the component having the same phase as the voltage component Vr2 of the commercial frequency component, That is, the leakage current Iorr1 of the effective leakage current Ior component flowing through the insulation resistance 9 is taken out and outputted to the analog / digital conversion unit 61 described above. 66), and the phase with the 90 degree shift voltage component (Vs3) corresponding to the S phase is The leakage current (Iocs1) component of the leakage current (Ioc) component of the leakage current (Ioc) flowing through the capacitance (8) of the same component is taken out and outputted to the analog / digital converting section (61). 62 is stored in the storage unit 66, and under the control of the operational control unit 62, the leakage current Io1 component of the commercial frequency component is in phase with the voltage component Vs2 of the commercial frequency component. Leakage current, i.e., leakage current Iors1 of the effective leakage current Ior component flowing through the insulation resistance 9, is taken out and outputted to the analog / digital conversion section 61, so that the arithmetic control section 62 is The leakage current (Ioc) component, which is stored in the storage unit 66 and flows through the leakage current of the component having the same phase as the 90-degree shift voltage component Vt3 corresponding to the T phase, that is, flows through the capacitance 8. Taking out the leakage current (Ioct1) component and outputting it to the analog-to-digital converter 61 The leakage current (Io1) component of the commercial frequency component is stored in the storage unit 66 through the arithmetic and control unit 62, and is again controlled by the arithmetic and control unit 62. The leakage current of the same phase as the phase, that is, the leakage current Iort1 of the effective leakage current Ior component flowing through the insulation resistance 9, is taken out and output to the analog / digital conversion unit 61 as described above. It is stored in the storage unit 66 via the control unit 62.

Then meet Iocr1 <k * Iorr1? When the flow 140 is executed, it is compared and judged whether the Iocr1 value which is the reactive leakage current component stored in the storage unit 66 is greater than or less than the product of the Iorr1 value which is the effective leakage current component multiplied by a constant constant (k). do. The above k value is a number greater than 0, but it is preferable that the value of k is different depending on the length of the cable line in the installation operation state of the cable line 3 or the capacitance at the input terminal of the load 4, etc., and in general, k Is preferably set to 1, and in the embodiment of the present invention, the value of k is set to 1. The reason is that if the effective leakage current Ior value and the invalid leakage current Ioc value are the same, the effective leakage current and the invalid leakage current detected on the secondary side of the image transformer 10 can be detected accurately. If the Iocr1 <k * Iorr1 condition satisfaction? Flow 140 is satisfied, i.e., if the Iorr1 value is greater than the Iocr1 value, the Iocs1 <k * Iorr1 condition satisfaction? Flow 200 is executed. If the Iocr1 value corresponding to the flowing reactive leakage current (Ioc) value is greater than the Iorr1 value corresponding to the effective leakage current (Ior) value flowing through the insulation resistance (9), the primary winding of the image current transformer (10) is R for calculating a value for forcing a component having the same phase as the reactive leakage current Ioc in the opposite direction to the leakage current flow of the reactive leakage current Ioc in order to reduce the flowing reactive leakage current Ioc. The ordinary effective fraction calculation flow 150 is executed.

When the R ordinary effective calculation flow 150 is executed, the data is executed in the various data read flows 110 and stored in the storage unit 66 and the above-mentioned Vr2, Vs2, Vt2, Vr3, Vs3, The Vr3 component executed in the Vt3 read & store flow 120 and stored in the storage unit 66 and the above Io1 read & store flow 130 and Iocr1, Iorr1, Iocs1, Iors1, Ioct1, Iort1 read & store flow 134 The values Iocr1 and Iorr1 stored in the storage unit 66 are stored in the voltage detectors 31a, 31b, 31c, the voltage filter units 32a, 32b, 32c, and 90 degrees or more (33a, 33b, 33c). The amplification factor related to the detection of the commercial frequency voltage component of the commercially available image converter 10, the current / voltage converter 41, the amplifier 42, the current filter 43 and the synchronous detector 44 Analog multipliers 52a, 52b, 52c having a function of multiplying (or mixing) two or more analog components with the amplification factor related to the leakage current component detection of the frequency components and the values of the commercial frequency components The arithmetic and control unit 62 using the same data as the amplification factor related to the removal of the ineffective leakage current component of the commercial frequency components of the compensating filter units 53a, 53b, and 53c having the function of taking out and converting them into current values. Through the calculation process, the R phase phase leakage leakage current value (Iocr3) of R phase which is about the same size as the reactive leakage current (Ioc) of the commercial frequency component by the capacitance (8) flowing between the actual cable (3) and the ground through Calculate The reactive phase removal leakage current value Iocr3 of R phase is calculated as follows, and the definition of the amplification factor or gain used in the following formula is as follows, and these values are set by the setting unit 63. The values are set or stored in the storage unit 66 in advance.

A1: Amplification-related coefficients of the voltage detectors 31a, 31b, and 31c

A2: Amplification-Related Coefficients of Voltage Filter Units 32a, 32a, and 32c

A3: Amplification-related coefficients over 90 degrees (33a, 33b, 33c)

B1: Amplification-related coefficients related to the primary / secondary winding ratio of the image transformer 10

B2: Amplification-Related Coefficients of Current / Voltage Converter 41

B3: Amplification-related coefficients of the current filter unit 43

B4: Amplification-related coefficients of the amplifier 43

B5: Amplification-related coefficients of the synchronization detector 44

C1: amplification-related coefficients of the analog multiplication sections 52a, 52b, 52c

C2: Amplification-related coefficients of the compensation filter units 53a, 53b, 53c

The conversion-related amplification coefficients of the analog / digital converter 61 and the digital / analog converters 51a, 51a, and 51c are set to one.

By substituting the Iocr value of Equation 1 above for the Iocr value of Equation 2 above, Iocr3 can be obtained as described above.

Next, when the R phase invalid fraction removal flow 160 is executed, the digital / analog value of the invalid fraction removal leakage current value Iocr3 of the commercial frequency component by the capacitance 8 calculated by the operation control section 62 is obtained. The value is sent to the conversion section 51a, and the digital / analog conversion section 51a is converted into an analog value and input to the analog multiplication section 52a. In the analog multiplication section 52a, the 90-degree voltage component Vr3 of the low frequency component detected by the 90-degree or higher portion 33a is calculated by the calculation control section 62, and the digital-to-analog conversion section 51a. Multiplying (mixing) of the reactive component removal leakage current value Iocr3 inputted through the signal and outputting it to the compensating filter unit 53a to have a 90 degree phase difference with the voltage of the commercial frequency component between the cable line 3 and the ground. The compensating filter unit 53a is once again filtered to be at the same frequency as the commercial frequency voltage between the cable line 3 and the ground, and in the opposite direction to the leakage current flowing between the cable line 3 and the ground in the image transformer 10. It converts into current value so that it can flow and sends it to the test line of the image transformer 10 or the reactive current compensation winding 21a, 21b, 21c which is composed of a plurality of auxiliary windings, and detects the secondary winding of the image transformer 10. Make sure that no reactive leakage current component is below a certain value.

Next, the Iorr1 and Iocr1 read flows 170 are executed to check whether the reactive leakage current due to the capacitance is detected by the video current transformer 10 and detected by the synchronization detector 44 as described above. The effective leakage current Iorr1 value and the invalid leakage current Iocr1 value are read by the operation control unit 62 through the analog / digital conversion unit 61, and the above Iocr1 <k * Iorr1 condition is satisfied? Iocr1 < k * Iorr1 condition satisfaction? Flow 180 identical to the flow 140 is determined by re-executing.

As described above, if the k-constant is k = 1, the reactive leakage current Iocr1 is larger than the effective leakage current Iorr1 even when the phase R invalid removal flow 160 is executed. If the reactive leakage current of the phase is continuously detected by the image transformer 10 to be higher than a predetermined value, the R phase invalid value correction calculation flow 190 similar to the R phase invalid value calculation 150 is executed again, and then R is again performed. The phase invalid fraction removal flow 160 is repeatedly executed. On the other hand, if the reactive phase leakage current Iocr1 of the R phase is smaller than the effective leakage current Iorr1 in the state where the phase R invalid removal flow 160 and the Iocr1 and Iorr1 read flows 170 are executed, the phase is invalid. The minute leakage current is detected by the image transformer 10 below a certain value, or the above Io1 read & store 130 and Iocr1, Iorr1, Iocs1, Iors1, Ioct1, Iort1 read & store flow 134 are executed. In the state where the reactive phase leakage current Iocr1 value of R is smaller than the effective leakage current Iorr1 value, Iocs1 <k * Iors1 condition satisfaction? Flow 200 is executed.

Then meet Iocs1 <k * Iors1? When the flow 200 is executed, it is compared and judged whether the value of Iocs1 which is the reactive leakage current component stored in the storage unit 66 is greater than or less than the value of Iors1 which is the effective leakage current component multiplied by a constant constant (k). do. If the Iocs1 <k * Iors1 condition satisfaction? Flow 200 is satisfied, i.e., if the Iors1 value is greater than the Iocs1 value, the Ioct1 <k * Iors1 condition satisfaction? Flow 260 is executed. If the Iocs1 value corresponding to the flowing reactive leakage current (Ioc) value is larger than the Iors1 value corresponding to the effective leakage current (Ior) value flowing through the insulation resistance (9), the primary winding of the image current transformer (10) is S for calculating a value for forcing a component having the same phase as the reactive leakage current Ioc in the opposite direction to the leakage current flow of the reactive leakage current Ioc in order to reduce the flowing reactive leakage current Ioc. The ordinary effective fraction calculation flow 210 is executed.

When the S phase effective calculation flow 210 is executed, the data is executed in the various data read flows 110 and stored in the storage unit 66 and the above-mentioned Vr2, Vs2, Vt2, Vr3, Vs3, The Vr3 component executed in the Vt3 read & store flow 120 and stored in the storage unit 66 and the above Io1 read & store flow 130 and Iocr1, Iorr1, Iocs1, Iors1, Ioct1, Iort1 read & store flow 134 The Iocs1 value and the Iors1 value stored in the memory 66 are stored in the voltage detectors 31a, 31b, 31c, the voltage filter units 32a, 32b, 32c, and the 90 degree or more portions 33a, 33b, 33c. The amplification factor related to the detection of the commercial frequency voltage component and the commercial frequency of the image transformer 10, the current / voltage converter 41, the amplifier 42, the current filter 43, and the synchronous detector 44 Analog multipliers 52a, 52b, 52c having a function of multiplying (or mixing) two or more analog components with the amplification factor related to the leakage current component detection of the components and the values of the commercial frequency components The arithmetic and control unit 62 using the same data as the amplification factor related to the removal of the ineffective leakage current component of the commercial frequency components of the compensating filter units 53a, 53b, and 53c having the function of converting the output and current values. Through the calculation process, the S phase phase leakage leakage current value (Iocs3), which is almost the same size as the reactive leakage current (Ioc) of the commercial frequency component due to the capacitance (8) flowing between the actual line (3) and the ground, is calculated through Calculate The reactive phase removal leakage current value Iocs3 of S phase is calculated as follows, and the definition of the amplification factor or gain used in the following calculation is as follows, and these values are set by the setting unit 63. The values are set or stored in the storage unit 66 in advance.

A1: Amplification-related coefficients of the voltage detectors 31a, 31b, and 31c

A2: Amplification-Related Coefficients of Voltage Filter Units 32a, 32a, and 32c

A3: Amplification-related coefficients over 90 degrees (33a, 33b, 33c)

B1: Amplification-related coefficients related to the primary / secondary winding ratio of the image transformer 10

B2: Amplification-Related Coefficients of Current / Voltage Converter 41

B3: Amplification-related coefficients of the current filter unit 43

B4: Amplification-related coefficients of the amplifier 43

B5: Amplification-related coefficients of the synchronization detector 44

C1: amplification-related coefficients of the analog multiplication sections 52a, 52b, 52c

C2: Amplification-related coefficients of the compensation filter units 53a, 53b, 53c

The conversion-related amplification coefficients of the analog / digital converter 61 and the digital / analog converters 51a, 51a, and 51c are set to one.

Substituting the Iocs value of Equation 3 into the Iocs value of Equation 4 above, Iocs3 can be obtained as described above.

Next, when the S-phase invalid fraction removing flow 220 is executed, the digital / analog value of the invalid fraction removal leakage current value Iocs3 of the commercial frequency component by the capacitance 8 calculated by the calculation control section 62 is obtained. The value is sent to the conversion section 51b, and the digital / analog conversion section 51b is converted into an analog value and input to the analog multiplication section 52b. In the analog multiplication section 52b, the 90-degree voltage component Vs3 of the low frequency component detected by the 90-degree or higher portion 33b is calculated by the calculation control section 62, and the digital / analog conversion section 51b. Multiplying (mixing) of the reactive component removal leakage current value Iocs3 inputted through the signal and outputting it to the compensating filter unit 53b to have a 90 degree phase difference with the voltage of the commercial frequency component between the cable line 3 and the ground. The compensating filter 53b is once again filtered to be at the same frequency as the commercial frequency voltage between the cable line 3 and the ground, and in the direction opposite to the leakage current flowing between the cable line 3 and the ground in the image current transformer 10. It is converted into a current value so that it can flow, and it is sent to the test current of the current transformer 10 or the reactive current compensation windings 21a, 21b, 21c, which are composed of a plurality of auxiliary windings, to the secondary winding of the image current transformer 10. Make sure that the reactive leakage current component detected is below a certain value.

Next, in order to confirm whether an invalid leakage current due to capacitance is detected in the image current transformer 10, the Iors1 and Iocs1 read flows 230 are executed to detect the synchronization detector 44 as described above. The effective leakage current Iors1 value and the invalid leakage current Iocs1 value are read by the operation control unit 62 through the analog / digital conversion unit 61, and the above Iocs1 <k * Iors1 condition is satisfied? Iocs1 < k * Iors1 condition satisfaction? Flow 240 identical to the flow 200 is determined by reexecuting the flow 240.

As described above, if the k-phase constant is k = 1, even if the above-mentioned phase S invalid flow removal flow 220 is executed, if the reactive leakage current Iocs1 is larger than the effective leakage current Iors1, that is, still S If the reactive leakage current of the phase is continuously detected by the image transformer 10 or more than a predetermined value, the S phase invalid value correction calculation flow 250 similar to the S phase invalid value calculation 210 is executed again, and then S is again performed. The phase invalid fraction removal flow 220 is repeatedly executed. On the other hand, if the invalid phase leakage current Iocs1 of the S phase is smaller than the effective leakage current Iors1 in the state where the S phase invalid fraction removal flow 220 and the Iocs1, Iors1 read flow 230 are executed, that is invalid. If the minute leakage current is detected below the constant value through the image current transformer 10, the Ioct1 <k * Iort1 condition is satisfied? Flow 200 is executed.

Then meet Ioct1 <k * Iort1? When the flow 260 is executed, it is compared to determine whether the Ioct1 value of the reactive leakage current component stored in the storage unit 66 is greater than or less than the value of the Iort1 value of the effective leakage current component multiplied by a constant constant (k). do. If Ioct1 <k * Iort1Condition Satisfaction? Flow 260 is satisfied, i.e., the Iort1 value is greater than the Ioct1 value, the Io2 read & store flow 320 is executed. If the Ioct1 value corresponding to the current (Ioc) value is larger than the Iort1 value corresponding to the effective leakage current (Ior) value flowing through the insulation resistance (9), the reactive leakage leakage flowing through the primary winding of the image current transformer (10) described above. T phase invalid calculation to calculate a value for forcing a component having the same phase as the reactive leakage current Ioc in the opposite direction to the leakage current flow of the reactive leakage current Ioc in order to reduce the current Ioc. Run flow 270.

When the T normal effective calculation flow 270 is executed, the data is executed in the various data reading flows 110 and stored in the storage unit 66 and the above-mentioned Vr2, Vs2, Vt2, Vr3, Vs3, The Vr3 component executed in the Vt3 read & store flow 120 and stored in the storage unit 66 and the above Io1 read & store flow 130 and Iocr1, Iorr1, Iocs1, Iors1, Ioct1, Iort1 read & store flow 134 The Iocs1 value and the Iors1 value stored in the memory 66 are stored in the voltage detectors 31a, 31b, 31c, the voltage filter units 32a, 32b, 32c, and the 90 degree or more portions 33a, 33b, 33c. The amplification factor related to the detection of the commercial frequency voltage component and the commercial frequency of the image transformer 10, the current / voltage converter 41, the amplifier 42, the current filter 43, and the synchronous detector 44 Analog multipliers 52a, 52b, 52c having a function of multiplying (or mixing) two or more analog components with the amplification factor related to the leakage current component detection of the components and the values of the commercial frequency components The arithmetic and control unit 62 using the same data as the amplification factor related to the removal of the ineffective leakage current component of the commercial frequency components of the compensating filter units 53a, 53b, and 53c having a function of converting the output and current values. Through the calculation process, the T phase reactive leakage current leakage value (Ioct3), which is almost equal to the reactive leakage current (Ioc) of the commercial frequency component by the capacitance (8) flowing between the actual cable line and the ground, is calculated through the calculation process. Calculate The reactive phase removal leakage current value Ioct3 of T phase is calculated as follows, and the definition of the amplification factor or gain used in the following calculation is as follows, and these values are set by the setting unit 63. The values are set or stored in the storage unit 66 in advance.

A1: Amplification-related coefficients of the voltage detectors 31a, 31b, and 31c

A2: Amplification-Related Coefficients of Voltage Filter Units 32a, 32a, and 32c

A3: Amplification-related coefficients over 90 degrees (33a, 33b, 33c)

B1: Amplification-related coefficients related to the primary / secondary winding ratio of the image transformer 10

B2: Amplification-Related Coefficients of Current / Voltage Converter 41

B3: Amplification-related coefficients of the current filter unit 43

B4: Amplification-related coefficients of the amplifier 43

B5: Amplification-related coefficients of the synchronization detector 44

C1: amplification-related coefficients of the analog multiplication sections 52a, 52b, 52c

C2: Amplification-related coefficients of the compensation filter units 53a, 53b, 53c

The conversion-related amplification coefficients of the analog / digital converter 61 and the digital / analog converters 51a, 51a, and 51c are set to one.

Substituting the Ioct value of Equation 5 above into the Ioct value of Equation 6 above, Ioct3 can be obtained as described above.

Next, when the T-phase reactive fraction removal flow 280 is executed, the digital / analog value of the invalid fraction removal leakage current value Ioct3 of the commercial frequency component by the capacitance 8 calculated by the operation controller 62 is obtained. The value is sent to the conversion unit 51c, and the digital / analog conversion unit 51c is converted into an analog value and input to the analog multiplication unit 52c. In the analog multiplication unit 52c, the 90-degree voltage component Vt3 of the low frequency component detected by the 90-degree or higher portion 33c is calculated by the calculation control unit 62, and the digital / analog conversion unit ( 51c) multiplies (mixes) the invalid component leakage current (Ioct3) input through 51c) and transmits it to the compensating filter unit 53c to have a 90-degree phase difference with the voltage of the commercial frequency component between the cable line 3 and the ground. . The compensation filter 53c is once again filtered to have the same frequency as the commercial frequency voltage between the cable line 3 and the earth, and is also in the opposite direction to the leakage current flowing between the cable line 3 and the earth in the image transformer 10. It converts into current value so that it can flow and sends it to the test line of the image transformer 10 or the reactive current compensation winding 21a, 21b, 21c which is composed of a plurality of auxiliary windings, and detects the secondary winding of the image transformer 10. Make sure that no reactive leakage current component is below a certain value.

Next, the Iort1 and Ioct1 read flows 290 are executed to check whether the reactive leakage current due to the capacitance is detected in the video current transformer 10 and detected by the synchronous detector 44 as described above. The effective leakage current Iort1 value and the invalid leakage current Ioct1 value are read by the operation control unit 62 through the analog / digital conversion unit 61, and the above Ioct1 <k * Iort1 condition is satisfied? Ioct1 < k * Iort1 condition satisfaction? Flow 300 identical to flow 260 is determined by re-execution.

As described above, if the k-phase constant is k = 1, the reactive leakage current Ioct1 is larger than the effective leakage current Iort1 even when the T-phase invalid component removal flow 230 is executed, that is, still T. If the reactive leakage current of the phase is continuously detected by the image transformer 10 or more than a predetermined value, the T phase invalidity correction calculation flow 310 similar to the T phase invalid fraction calculation 270 is executed again, and then T is again performed. The phase invalid fraction removal flow 270 is repeatedly executed. On the other hand, if the invalid phase leakage current Ioct1 of the T phase is smaller than the effective leakage current Iort1 in the state where the T phase invalid fraction removal flow 270 and the Ioct1, Iort1 read flow 290 are executed, that is invalid. If the minute leakage current is detected below the constant value through the image current transformer 10, the Io2 read & store flow 230 is executed.

When the Io2 read & store flow 320 is executed, the leakage current Io2 of the commercial frequency component is extracted from the current filter unit 43 in the same manner as the Io1 read & store flow 130 described above. The analog / digital conversion unit 61 outputs the data to the analog / digital conversion unit 61 and stores the data in the storage unit 66 through the operation control unit 62.

Next, when Iocr2, Iorr2, Iocs2, Iors2, Ioct2, and Iort2 read & store flow 330 are executed, the leakage current (Io1) component of the commercial frequency component taken out from the current filter unit 43 and the above voltage fill Voltage components Vr2, Vs2, and Vt2 of the commercial frequency components extracted from the terminators 32a, 32b, and 32c, and 90 degree shift voltage components Vr3, Vs3, Vt3) Six components are input to the synchronous detection section 44 for synchronous detection of phase. In the synchronous detection unit 44, the leakage of the component having the same phase as the 90-degree shift voltage component Vr3 corresponding to the R phase among the leakage current Io2 components of the commercial frequency component under the control of the operation control unit 62. The leakage current (Iocr2) component of the current, i.e., the reactive leakage current (Ioc) component flowing in the capacitance (8), is taken out and output to the analog / digital converter (61), through the arithmetic and control unit (62). The leakage current of the component having the same phase as the voltage component Vr2 of the commercial frequency component is stored in the storage unit 66 and is again controlled by the operation control unit 62. That is, the leakage current Iorr2 of the effective leakage current Ior component flowing through the insulation resistance 9 is taken out and outputted to the analog / digital conversion unit 61 described above, and stored in the storage unit through the operation control unit 62. Stored in (66), and the phase with the 90-degree shift voltage component Vs3 corresponding to the S phase The leakage current (Iocs2) component of the leakage current (Ioc) component of the leakage current (Ioc) flowing through the capacitance (8) of the same component is taken out and outputted to the analog / digital conversion unit (61). 62 is stored in the storage unit 66, and the control unit 62 controls the leakage current Io2 component of the commercial frequency component to be in phase with the voltage component Vs2 of the commercial frequency component. Leakage current, i.e., leakage current Iors2 of the effective leakage current Ior component flowing through the insulation resistance 9, is taken out and outputted to the analog / digital conversion unit 61, so that the arithmetic control unit 62 is The leakage current (Ioc) component, which is stored in the storage unit 66 and flows through the leakage current of the component having the same phase as the 90-degree shift voltage component Vt3 corresponding to the T phase, that is, flows through the capacitance 8. Taking out the leakage current (Ioct2) component and outputting it to the analog-to-digital converter 61 The leakage current (Io2) component of the commercial frequency component is stored in the storage unit 66 through the arithmetic and control unit 62, and is again controlled by the arithmetic and control unit 62. The leakage current Iort2 of the effective leakage current Ior component flowing through the insulation resistance 9, i.e., the leakage current Iort2 having the same phase as that of the component, is taken out and output to the analog / digital conversion unit 61 as described above. It is stored in the storage unit 66 via the control unit 62.

Next, when the calculation & display flow 340 is executed, various data stored in the storage unit 66 in each of the above flows, for example, Vr2, Vs2, Vt2, Vr3, Vs3, Vt3, Io1, Ioc1, Ior1, Io2 Using the detected data such as Ioc2, Ior2, and amplification-related coefficients, it can be expressed by the following formula.

The effective leakage current Ior flowing through the insulation resistance 9 flowing between the cable line 3 and the ground can be calculated by the following equation.

The image leakage current Io flowing between the cable line 3 and the ground can be calculated by the following expression (8).

The insulation resistance (R) between the cable line (3) and the ground can be calculated by the following equation (9).

The reactive leakage current Ioc flowing in the capacitance 8 flowing between the cable line 3 and the ground can be calculated by the following expression (10).

 As shown in Equation 1 to Equation 10 described above, various kinds of leakage current values and insulation resistance values can be calculated, and even if a large amount of reactive leakage current (Ioc) leaked to the ground due to capacitance, The effective leakage current (Ior) due to the insulation resistance can be detected accurately, and the image leakage current (Io) flowing between the actual cable line 3 and the ground can be detected and calculated as described above. The leakage current (Ior) as well as the image leakage current (Io) data can be displayed on the display means of the kind such as FND or LCD or the leakage current value or state on the display unit 64 to output to the display means such as LED or buzzer. have.

In addition, as described above, the insulation resistance R value due to the voltage between the actual cable line 3 and the ground can be automatically calculated and displayed on the display unit 64.

In addition, the reactive leakage current caused by the capacitance flowing from the actual cable line 3 to the ground using the reactive leakage current component Ioc1 read before the compensation of the reactive leakage current is stored in the storage unit 66 ( Ioc) can be calculated and displayed on the display unit 64,

In addition, by using the setting unit 63 having a function of inputting or selecting various data by means of a kind of a switch or a keypad, the various leakage current components and insulation resistance values are selectively displayed on the display unit 64, or If the alarm level is greater than the alarm level (leakage current) or less than the alarm level input by the setting unit 63 or the alarm level stored in the storage unit 66, the insulation section is displayed. 64 may display an alarm state, or may output various data or alarm alarms calculated above through the external output unit 65.

Next, FIG. 4 which is an explanatory view of the second connection connection of the insulation monitoring system in the three-phase wire of the present invention will be briefly described.

Although briefly described with reference to FIG. 4, the major difference between FIG. 3 and FIG. 4 is an example in which the image current transformer 10, which is a leakage current detecting means, is connected between the transformer 1 and the load 4. The current transformer 10 is for explaining that any part of the current path 10 between the transformer 1 and the load 4 can be connected and installed. The current path 10 after the image current transformer 10 is installed. ) And only the insulation state of the load 4 can be detected. In FIG. 4, the image current transformer 10 is installed in the middle of the ground line 5 connecting the transformer 1 and the ground 6. It will be explained that the insulation state of all the wires 3 and the loads 4 supplied from the secondary side of the transformer 1 can be detected.

Next, FIG. 5 which is an explanatory drawing of the third connection connection of the insulation monitoring system in the three-phase electric wire of the present invention will be briefly described.

FIG. 5, which is a third connection connection explanatory diagram, is similar to FIG. 3 described above, and FIG. 3 illustrates a three-phase three-wire system, while FIG. 5 illustrates that the present invention can be used in three-phase four-wire systems. The rest is the same as FIG. 3.

Next, Fig. 6, which is an explanatory diagram of a fourth connection connection of the insulation monitoring system in the three-phase wire of the present invention, will be briefly described.

FIG. 6 is described with a wire connection, which is a secondary connection of the transformer 1 as shown in FIG. 3 and FIG. 5, and in FIG. 3 and FIG. 5, the voltage detecting means uses all three phases R, S, and T. 6 shows that the present invention can be configured even when only one voltage detecting means is used, and the voltage detecting means is described in detail with reference to FIGS. 15 to 17 of the insulation monitoring apparatus 12. I only use one. 3 to 5, three reactive current compensation windings are used for each phase. However, in FIG. 6, the present invention can be implemented using only one reactive current compensation winding. For the purpose of explanation, FIG. 14 illustrates the insulation monitoring device 12 in detail, and shows an example in which only one reactive current compensation winding is implemented.

Next, FIG. 7 which is a connection connection explanatory drawing of the insulation monitoring system 5 in the three-phase electric wire of this invention is demonstrated briefly.

FIG. 7 is a combination of the matter of using the video current transformer 10 of FIG. 4 described above in the middle of the ground line 5, using three reactive current compensation windings, and using only one voltage detecting means of FIG. In this case, even if only one voltage detecting means is used, the present invention can be implemented even when the video current transformer 10 is provided in the middle of the ground line 5.

Next, FIG. 8, which is a connection diagram of the sixth insulation monitoring system in the three-phase electric wire of the present invention, will be briefly described.

FIG. 8 is an explanatory view for explaining that the present invention can be used in the secondary connection of the transformer 1 even in the delta connection, and using three voltage detection lines and only one reactive current compensation winding. .

Next, FIG. 9 which is a connection explanatory drawing of the insulation monitoring system 7 in the three-phase electric wire of this invention is demonstrated briefly.

FIG. 9 is an explanatory view for explaining that the present invention can be used in the secondary connection of the transformer 1 even in the delta connection, and in the case of using one voltage detection line and two reactive current compensation windings. .

Next, Fig. 10, which is a connection explanatory diagram of the insulation monitoring system 8 of the three-phase electric wire of the present invention, will be briefly described.

FIG. 10 shows that the present invention is implemented even when the installation position of the image transformer 10 is installed in the middle of the ground line 5 using one voltage detection line and one reactive current compensation right as described above. It is explanatory drawing for demonstrating that it can be done.

Next, Fig. 12, which is a second embodiment of the insulation monitoring device 12 for three-phase wire of the present invention, will be briefly described.

In FIG. 11, a first embodiment of the insulation monitoring device 12 described above, the internal structure of the insulation monitoring device 12 that detects, calculates, controls, and displays the leakage current is connected to the leakage current component through the image current transformer 10. Detects and converts the leakage current component into a voltage component in the current / voltage converter 41, and amplifies the value converted into the voltage component through the amplifier 42 and converts the amplified value into a current filter unit ( 43), but only the values of the commercial frequency components are taken out, but in FIG. 12, which is the second embodiment of the insulation monitoring apparatus 12, the leakage current component is detected through the image current transformer 10, and this value is converted into current / current. After converting the voltage component 41 into a voltage component, the amplifier 42 first amplifies the voltage component and then extracts only the value of the commercial frequency component from the current filter 43. In other words, the positions of the amplifier 42 and the current filter 43 are changed in order, and the values input to the synchronous detector 44 and the analog / digital converter 61 are the current filter units in FIG. 11. In FIG. 12, the output value of the amplifier 42 is used in FIG. 12, and the effective value due to the very small insulation resistance detected by the image current transformer 10 due to the large amount of leakage current caused by the capacitance. Reducing Inaccuracy in Detection of Leakage Current A method of detecting, calculating and displaying an output leakage current by the insulation resistance after flowing in the direction opposite to the direction of the reactive leakage current due to the capacitance flowing to the ground in the image transformer 10 Same as the embodiment described above.

Next, FIG. 13, which is a third embodiment of the insulation monitoring device 12 for three-phase wire of the present invention, will be briefly described.

In FIG. 11, which is the first embodiment of the insulation monitoring apparatus 12 described above, the reactive leakage current Ioc between the cable line 3 and the ground is large, and is directly related to a short circuit detected by the image current transformer 10. In order to solve the problem that the detection of the active component leakage current (Ior) component is incorrectly detected, when the reactive component leakage current (Ioc1) component extracted through the synchronous detector 44 is greater than a certain number of the effective component leakage current (Ior1) The ineffective portion calculated by the calculation controller 62 to flow in the direction opposite to the leakage current flowing between the cable line 3 and the ground to the reactive current compensation winding 21 of the image current transformer 10 by calculation in the calculation controller 62. The removal leakage current Ioc3 is passed through the digital / analog converter 51, the analog multiplier 52, and the compensation filter 53 to the reactive current compensation winding 21 to be detected by the synchronous detector 44. Lost inactive value Leakage current (Ioc1) is an effective multiple of a certain multiple While it is configured to control to be smaller than the snow current Ior1, in FIG. 13, the third embodiment shifts the phase of the voltage component between the cable line 3 and the ground taken out of the 90 degree portion 33 by 90 degrees. The analog voltage component of a 90-degree shift voltage component Va3 is converted to a 90-digit shift voltage component of a digital component that is converted to a digital value of high when the value is greater than zero and a low value when the value is less than zero. In the waveform shaping unit 56, the digital value obtained by multiplying (or mixing) the sequential value and the invalid component removal leakage current value Ioc3 of the digital component calculated by the operation control unit 62 with the digital multiplier 55 is phased. Compensation filter unit by converting to a component having a waveform of the analog component that is the same as the phase of the above 90 degrees 33, the magnitude is equal to the value of the invalid component removal leakage current calculated by the operation control unit 62 Output to 53 By way of example, the static electricity flowing to the earth to the image transformer 10 reduces the inaccuracy of detection of the effective leakage current due to the very small insulation resistance detected by the image transformer 10 due to the large amount of the leakage current due to the capacitance. The method of detecting, calculating, and outputting the effective leakage current by the insulation resistance after flowing in the direction opposite to the reactive leakage current by the capacitance is not significantly different from the above-described embodiment.

Next, FIG. 14 which is 4th Example of the insulation monitoring apparatus 12 for three-phase electric wires of this invention is demonstrated briefly.

In FIG. 11, which is the first embodiment of the insulation monitoring device 12 described above, three voltage detecting means 22a, 22b, 22c and three voltage detecting parts 31a, 31b, 31c are used to detect voltage components of three phases. And three voltage filter units 32a, 32b, and 32c, but in FIG. 14, the fourth embodiment, one voltage detecting means 22a, or 22b or 22c is used to detect voltage components of three phases. And one voltage detection unit 31 and one voltage filter unit 32 first detect the voltage component of one commercial frequency component, and then the other one in the 120-degree phase section 34 shifting the phase by 120 degrees. The difference is that the voltage components of the three phases are detected by converting them into voltage components of the phase, and converting them into voltage components of another phase in the 240 degree phase portion 35 which shifts the phase by 240 degrees. In more detail, the insulation monitoring device is detected by the voltage detecting means 22a (22b for detecting the voltage of S phase and 22c for detecting the voltage of T phase) to detect the voltage of R phase. The commercial AC voltage inputted to (12) is converted into a constant voltage value that can be used in the insulation monitoring device 12 by using the resistance component, the capacitor component or the coil component in the voltage detector 31, and the voltage detector ( The voltage component converted in (31) is a mixed value with values of various frequency components, and thus the voltage filter unit 32 extracts voltage components of a predetermined frequency or less or a commercial frequency band. The voltage component taken out from the dedicated filter unit 32 is a component value corresponding to one of three phases, that is, R phases. Phase shifting the voltage component by 120 degrees at the 120 degree or more portion 34 extracts the voltage component corresponding to the S phase, and phase shifting by 240 degrees at the 240 degree or more portion 35 of the R phase results in a voltage component corresponding to the T phase. The voltage component of the common frequency component of the three phases can be detected by extraction and the other matters are the same as in FIG.

Next, FIG. 15 which is 5th Example of the insulation monitoring apparatus 12 for three-phase electric wires of this invention is demonstrated briefly.

As shown in FIG. 14, which is the fourth embodiment described above, the voltage component detection uses one voltage detection means, and the compensation filter units 53a, 53b, and 53c use one current component to convert the three-phase current components of the commercial frequency components. To the reactive current leakage winding by the capacitance 8 to one reactive current compensation winding 21 or the test winding of the current transformer 10 so as to flow in the opposite direction to the secondary side of the current transformer 10. The computational control unit 62 is controlled so that the ineffective leakage current caused by the capacitance 8 hardly flows. Other matters are almost the same as those in FIG.

Next, FIG. 16 which is a 5th Example of the insulation monitoring apparatus 12 for three-phase electric wires of this invention is demonstrated briefly.

In the fifth embodiment described above, in FIG. 15, the voltage component of one phase is detected using one voltage detecting means, the voltage detecting unit 31, and one voltage filter unit 32. The voltage components of the remaining two phases are extracted using the 240 degree phase shifter 35. However, in FIG. 16, the voltage components of the remaining two phases can be taken out using the two 120 degree phase shifters 34b and 34c. In the fifth embodiment, Fig. 15, which uses three digital / analog converters 51a, 51b, and 51c, is used. However, in the present embodiment, Fig. 16 shows one digital / analog having three or more channels. It is for explaining that the present invention can also be implemented using the converting unit 51.

Next, FIG. 17, which is a seventh embodiment of the insulation monitoring device 12 for three-phase wire of the present invention, will be briefly described.

In the sixth embodiment described above, one digital / analog converter 51 is used, and in FIG. 11, the first embodiment, three voltage detection means 22a, 22b, and 22c are used. As an example in which the embodiments are mixed, the present invention as described above is for explaining that various insulation monitoring devices 12 can be implemented.

In the embodiment of the present invention, the voltage detecting unit 31 is formed on the wire line 3 so as to detect the voltage phase and magnitude, but the portion having the function of the voltage detecting unit 31 is provided. There may be an embodiment configured to the outside of the insulation monitoring device 12, the current / voltage conversion unit 41 to the internal configuration of the insulation monitoring device 12 to detect the leakage current, but the image current transformer 10 When an electronic component element such as a resistor is directly connected to the secondary side of the insulation monitoring device 12, a part having a function of the current / voltage converter 41 may be configured outside the insulation monitoring device 12. In addition, there may be an embodiment constituting the amplifier 42 having a function of the current / voltage conversion unit 41, an embodiment in which the positions of the amplifier 42 and the current filter unit 43 of FIG. May be present in place of the analog multiplication units 52a, 52b, 52c The present invention can be used in various ways without departing from the gist of the present invention, such as a digital multiplier having the same function as the analog multiplier, and one analog multiplier having three channels. If you are a technician working on a related task, it is clear that it is easy to apply.

As described above, the present invention detects the leakage current component Io flowing between the earth of the cable line 3 through the image current transformer 10 and amplifies the leakage current Io through the amplifier 42. The amplified leakage current component is extracted through the current filter unit 43 for the leakage current component Io1 of the commercial frequency component, or the leakage current Io detected through the image current transformer 10 is used for the current filter unit 43. The common frequency component is extracted through the circuit and through the amplification unit 42, the leakage current component Io1 of the commercial frequency component amplified by the amplifier 42 and the voltage detection means 22a and 22b are connected to the wire. The voltage component Va2 from which the voltage of the commercial frequency component is extracted through the voltage filter unit 32 for detecting the commercial AC voltage of (3) and the voltage of the commercial frequency component is detected. The voltage component (Va3) phase shifted by 90 degrees through Phase synchronous detection is performed by the leakage current unit Io1 and the synchronous detection unit 44 of the commercial frequency component extracted by the unit 43 or the amplification unit 42, respectively, to effectively phase in phase with the voltage component Va2. The minute leakage current Ior1, the 90-phase phase shift voltage component Va3, and the in-phase reactive leakage current Ioc1 are detected, and the detected leakage current Ior1 and the invalid leakage current Ioc1 are detected. ) Is stored in the storage unit 66 through the analog / digital converter 61 and the operation controller 62, and the effective leakage current Ior1 value read through the analog / digital converter 61 is When the leakage current (Ioc1) value of the reactive portion is compared and the leakage current (Ioc1) value of the reactive portion is larger than the leakage current (Ior1) value of the effective portion of the constant multiple (k), that is, the leakage current (I) due to the capacitance (8) If a large amount of leakage current of Ioc) flows, the computation control unit 62 calculates the value of the removal leakage current Ioc3 of the invalid portion by calculation. Voltage component Va3 through the 90-degree phase section through the analog converter 51 and the invalid component having a 90-degree phase difference from the commercial frequency alternating voltage through the multiplier and compensation filter section 53 by the analog multiplier 52 The leakage current flows in the opposite direction to the image transformer 10 so that the leakage current Ioc1 value of the invalid portion detected by the synchronous detector 44 through the image transformer 10 is equal to or less than a predetermined value. In the state controlled by the conversion unit 61 and the operation control unit 62, the effective leakage current Ior2 detected by the synchronous detection unit 44 can be accurately detected. The reactive current leakage current Ioc due to the capacitance 8 component present at the input terminal of the load 4 is much larger than the effective leakage current Ior due to the insulation resistance 9 component, so that the image current transformer 10 The effective leakage current (Ior) detected through The problem can be solved, and the leakage current Ior of the effective portion as well as the image leakage current detected by the current filter 43 or the amplifier 42 and stored in the storage 66 The current leakage current of the commercial frequency component due to the capacitance and insulation resistance actually flowing from the cable line 3 to the ground, which was detected and used in the conventional conventional method by the calculation by the calculation controller 62 using the value of Io1). (Io) can also be detected and displayed, which can be compared with the conventional conventional measurement values. In addition, by using the voltage between the cable line 3 and the ground detected through the voltage detecting means 22a and 22b, the calculation control unit 62 automatically calculates the insulation resistance value R instead of the leakage current value. There is also an effect that can be calculated and displayed. In addition, an alarm state is displayed on the display unit 64 by a method of comparing with the alarm level input from the setting unit 63 or the alarm level stored in the storage unit 66, or communicating with a remote control device located at a remote location. Alternatively, an output unit 65 having a controllable function may also be configured to remotely monitor various data or alarm states detected remotely.

Claims (6)

In the insulation monitoring system for detecting the insulation state of the three-phase wire in the live state, An analog / digital converter having a function of converting an analog value into a digital value; A digital / analog converter having a function of converting a digital value into an analog value; An analog multiplication unit having a function of multiplying (or mixing) analog components; A setting unit having a function of setting and inputting various data by using a kind of component such as a keypad or a switch; A display unit capable of displaying various data or displaying alarms; An operation control unit for reading and outputting various data and having an operation function; A storage unit having a function of storing various data; Voltage detecting means for detecting a voltage component of the cable line to accurately detect and monitor an effective leakage current of the insulation resistance component existing between the earth even if the capacitance component existing between the wire path and the earth is very large; A voltage detector for converting the voltage component detected by the voltage detector into a predetermined voltage; A voltage filter unit for extracting a voltage component of a commercial frequency component among the voltage components converted through the voltage detector; 90 degrees or more for shifting the phase of the voltage of the commercial frequency component extracted through the voltage filter unit by 90 degrees; An image current transformer for detecting an image leakage current flowing between an electric line and a ground; A current / voltage converter for converting the current value of the image leakage current component detected by the secondary side of the image current transformer into a voltage value; An amplifier for amplifying the image leakage current component converted into a voltage component through the current / voltage converter; A current filter unit for extracting commercial frequency components among the image leakage current components amplified by the amplifying unit; Phase synchronizing the video leakage current component of the commercial frequency component extracted through the current filter unit with the voltage component of the commercial frequency component extracted through the voltage filter unit and the 90-degree shift voltage component converted in the above 90 degree portion. A synchronization detector for detecting; A reactive current compensation winding having a function of an auxiliary winding by being separately provided with a test cable or on a primary side of the image current transformer; Insulation monitoring system, characterized in that consisting of; compensating filter unit having a function to take out the commercial frequency components and to flow the current to the reactive current compensation winding of the video current transformer; In the insulation monitoring system for detecting the insulation state of the three-phase wire in the live state, An analog / digital converter having a function of converting an analog value into a digital value; A zero cross section having a function of converting an AC component into a digital component by comparing magnitudes at zero points; A digital multiplier having a function of multiplying (or mixing) two digital components; A waveform shaping unit having a function of converting a digital value into an analog value and shaping a waveform; A setting unit having a function of setting and inputting various data by using a kind of component such as a keypad or a switch; A display unit capable of displaying various data or displaying alarms; An operation control unit for reading and outputting various data and having an operation function; A storage unit having a function of storing various data; Voltage detecting means for detecting a voltage component of the cable line to accurately detect and monitor an effective leakage current of the insulation resistance component present between the earth even when the capacitance component existing between the wire path and the earth is very large; A voltage detector for converting the voltage component detected by the voltage detector into a predetermined voltage; A voltage filter unit for extracting a voltage component of a commercial frequency component among the voltage components converted through the voltage detector; 90 degrees or more for shifting the phase of the voltage of the commercial frequency component extracted through the voltage filter unit by 90 degrees; An image current transformer for detecting an image leakage current flowing between an electric line and a ground; A current / voltage converter for converting the current value of the image leakage current component detected by the secondary side of the image current transformer into a voltage value; An amplifier for amplifying the image leakage current component converted into a voltage component through the current / voltage converter; A current filter unit for extracting commercial frequency components among the image leakage current components amplified by the amplifying unit; Phase synchronizing the video leakage current component of the commercial frequency component extracted through the current filter unit with the voltage component of the commercial frequency component extracted through the voltage filter unit and the 90-degree shift voltage component converted in the above 90 degree portion. A synchronization detector for detecting; A reactive current compensation winding having a function of an auxiliary winding by being separately installed on a test line of the image current transformer; Insulation monitoring system, characterized in that consisting of; compensating filter unit having a function to take out the commercial frequency components and to flow the current to the reactive current compensation winding of the video current transformer; In the insulation monitoring system for detecting the insulation state of the three-phase wire in the live state, An analog / digital converter having a function of converting an analog value into a digital value; A digital / analog converter having a function of converting a digital value into an analog value; An analog multiplication unit having a function of multiplying (or mixing) two analog components; A setting unit having a function of setting and inputting various data by using a kind of component such as a keypad or a switch; A display unit capable of displaying various data or displaying alarms; An operation control unit for reading and outputting various data and having an operation function; A storage unit having a function of storing various data; Voltage detecting means for detecting a voltage component of the cable line to accurately detect and monitor an effective leakage current of the insulation resistance component existing between the earth even if the capacitance component existing between the wire path and the earth is very large; A voltage detector for converting the voltage component detected by the voltage detector into a predetermined voltage; A voltage filter unit for extracting a voltage component of a commercial frequency component among the voltage components converted through the voltage detector; 120 degrees or more for shifting the phase of the voltage of the commercial frequency component extracted through the voltage filter unit by 120 degrees; 240 degrees or more for shifting 240 degrees; 90 degrees or more for shifting the voltage phase of the voltage filter unit 120 degrees or more and 240 degrees or more by 90 degrees; An image current transformer for detecting an image leakage current flowing between an electric line and a ground; A current / voltage converter for converting the current value of the image leakage current component detected by the secondary side of the image current transformer into a voltage value; An amplifier for amplifying the image leakage current component converted into a voltage component through the current / voltage converter; A current filter unit for extracting commercial frequency components among the image leakage current components amplified by the amplifying unit; Converts the image leakage current component of the commercial frequency component extracted through the current filter unit from the voltage filter unit and the voltage component of the commercial frequency component extracted through the above 120 degree part and the above 240 degree part and the above 90 degree part. A synchronous detector for phase-synchronizing the detected 90 degree shift voltage component; A reactive current compensation winding having a function of an auxiliary winding by being separately installed on a test line of the image current transformer; Insulation monitoring system, characterized in that consisting of; compensating filter unit having a function to take out the commercial frequency components and to flow the current to the reactive current compensation winding of the video current transformer; In the insulation monitoring system for detecting the insulation state of the three-phase wire in the live state, An analog / digital converter having a function of converting an analog value into a digital value and a digital / analog converter having a function of converting a digital value into an analog value; An analog multiplication unit having a function of multiplying (or mixing) two analog components; A setting unit having a function of setting and inputting various data by using a kind of component such as a keypad or a switch; A display unit capable of displaying various data or displaying alarms; An operation control unit for reading and outputting various data and having an operation function; A storage unit having a function of storing various data; Voltage detecting means for detecting a voltage component of the cable line to accurately detect and monitor an effective leakage current of the insulation resistance component existing between the earth even if the capacitance component existing between the wire path and the earth is very large; A voltage detector for converting the voltage component detected by the voltage detector into a predetermined voltage; A voltage filter unit for extracting a voltage component of a commercial frequency component among the voltage components converted through the voltage detector; 120 degrees or more for shifting the phase of the voltage of the commercial frequency component extracted through the voltage filter unit by 120 degrees; 90 degrees or more for shifting the voltage phase of the voltage filter unit and the 120 degrees or more by 90 degrees; An image current transformer for detecting an image leakage current flowing between an electric line and a ground; A current / voltage converter for converting the current value of the image leakage current component detected by the secondary side of the image current transformer into a voltage value; An amplifier for amplifying the image leakage current component converted into a voltage component through the current / voltage converter; A current filter unit for extracting commercial frequency components among the image leakage current components amplified by the amplifying unit; The image leakage current component of the commercial frequency component extracted through the current filter unit and the voltage component of the commercial frequency component extracted through the voltage filter unit and 120 degrees or more and the 90 degree shift voltage converted from the 90 degrees or more. A synchronous detection section for phase synchronous detection of components; A reactive current compensation winding having a function of an auxiliary winding by being separately installed on a test line of the image current transformer; Insulation monitoring system, characterized in that consisting of; compensating filter unit having a function to take out the commercial frequency components and to flow the current to the reactive current compensation winding of the video current transformer; The leakage current value is greater than the alarm set value or the insulation resistance value is smaller than the alarm set value as compared with the alarm set value set in the setting section or the alarm set value stored in the storage section. Insulation monitoring system, characterized in that it can display the alarm alarm to the outside by means such as buzzer, LED, relay in the display unit The insulation monitoring system according to any one of claims 1, 2, 3, 4, or 5, further comprising an input / output unit for remote monitoring from the outside.

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