KR101276170B1 - Electric Leakage Detecting System - Google Patents

Abstract

The present invention relates to an earth leakage detection system for monitoring a resistance component directly related to an earth leakage regardless of the magnitude of the capacitance present in the converter and load input terminals in an uninterrupted live state. The reactive leakage current value of the capacitance component present in the capacitor is so large that the effective leakage current value due to the resistance component directly related to the leakage current is detected due to the influence of the reactive leakage current value due to the capacitance component not directly related to the leakage current. In order to solve the growing problem, the reactive leakage current component caused by the capacitance flows to the leakage current detection means in the opposite direction to the reactive leakage current component due to the capacitance so that the leakage current component caused by the capacitance flows very small to the leakage current detection means, thereby directly causing leakage. It detects the effective leakage current of insulation resistance component with high sensitivity and It relates to a hot-line leak detection system of a low pressure before displaying the resistance value is monitored.

Leakage current, live wire, uninterrupted power, low voltage converter, active ingredient

Description

Electric Leakage Detecting System

1 is a diagram illustrating a conventional ground fault detection system in a live state

2 is an explanatory diagram of a conventional ground fault detection system in a live state

3 is an explanatory diagram of a first connection connection of a ground fault detection system in a single phase converter according to the present invention;

4 is an explanatory diagram of a connection connection of a second earth leakage detection system in a single phase converter according to the present invention;

FIG. 5 is an internal detailed view of Embodiment 1 of an earth leakage detecting apparatus used in FIGS. 3 and 4 of the present invention;

FIG. 6 is an internal detailed view of Embodiment 2 of an earth leakage detecting apparatus used in FIGS. 3 and 5 of the present invention;

7 is an operational flow used in the first and second embodiments of the earth leakage detecting apparatus for a single phase converter according to the present invention.

8 is another explanatory diagram of a conventional ground fault detection system in a live state;

FIG. 9 is an internal detailed explanation view of Embodiment 3 of the ground fault detection apparatus used in FIGS. 3 and 5 of the present invention;

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

1: high / low voltage transformer 2: switchgear

3: converter (line) 4: load equipment

5: ground wire 6: ground for transformers

7: Ground 8: Capacitance of the converter

9: Ground-to-earth insulation resistance of converter 10: Image transformer

12: ground fault detection device

21: reactive current compensation winding 22a, 22b: voltage detection means

31: voltage detector 32: voltage filter unit

33: 90 degrees or more

41: current / voltage converter 42: amplifier

43: current filter unit 44: synchronous detector

51: digital / analog converter 52: analog multiplier

53: compensation filter unit 54: zero cross unit

55: digital multiplication section 56: waveform shaping section

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

63: setting unit 64: display unit

65: output unit 66: storage unit

According to the present invention, the leakage current is not directly related to the leakage current in the live state in the live state and in the converter and the load input terminal, without directly interrupting the insulation state of the single-phase low-voltage converter. In an earth leakage detection system for detecting an effective leakage current or insulation resistance value of a 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 single-phase converter is detected, and the leakage current corresponding to the AC current component (60 Hz or 50 Hz) is detected. After detecting through the image current transformer, the leakage current corresponding to the invalid portion corresponding to the 90 degree phase difference of the detected commercial AC voltage is extracted and the current corresponding to the leakage current component corresponding to the invalid portion is detected. After flowing the current to the current transformer in the opposite direction to the leakage current, the leakage current corresponding to the invalid portion is erased, and the effective current directly related to the short circuit The present invention relates to a short-circuit detection system that monitors only the leakage current component corresponding to the minute, so that the leakage current of the effective portion is accurately detected in the image current transformer, and displays the insulation resistance value and the effective leakage current value corresponding to the resistance component.

It also detects the leakage current (Io) flowing between the low voltage converter and the ground before removing the reactive leakage current, and uses it as a comparison data.Also, an alarm is generated when the detected data is larger than the preset leakage current alarm set value. Can be done.

Conventionally, as an apparatus for detecting and monitoring an insulation state of a single-phase low-voltage converter in a live state, that is, a short circuit, as shown in FIG. 1, the current transformer 10 is located in the middle of the converter 3 between the transformer 1 and the load 4. ) Is a vector sum of the effective leakage current (Ioc) due to the leakage current due to the capacitance (8) flowing between the converter (3) and the earth (7) and the effective leakage current (Ior) due to the insulation resistance (9). The image leakage current (Io = Ior + Ioc) corresponding to the above is detected by the image transformer 10, and the leakage current Io detected by the image transformer 10 is amplified by the ground fault detection device 12. An earth leakage detection system such as an earth leakage alarm or a leakage current meter which displays an alarm when filtered and is larger than a preset value or displays a detected leakage current value has been generally used. Similar devices include an earth leakage relay, an earth leakage circuit breaker, a clamp meter, and the like. As shown in FIG. 2, the image current transformer 10 is installed in the middle of a ground line 5 grounded at one end of a transformer 1. The earth leakage detection system for detecting the image leakage storage Io flowing through the ground line 5 has been described and corresponds to the earth leakage detection system similar to FIG. 1 described above. The earth leakage detection system which detects the image leakage current Io described above and monitors the earth leakage state is performed when the effective leakage current Ior and the line are long due to the insulation resistance 9 existing between the converter 3 and the earth. Since it is detected as a vector sum of the reactive leakage current (Ioc) by the capacitance 8 generated by the generated capacitance and the noise filter inserted into the input terminal of the load facility, the insulation resistance does not occur and the insulation resistance does not occur. Even if very good, the capacitance is very large, the reactive leakage current (Ioc) due to the capacitance component is also large, there has been a problem that the insulation state is poor, that is, it is measured and detected that a short circuit or an uninterrupted occurrence occurred.

Because of this problem, foreign countries use the Japanese Utility Model Publication No. Hei 7-29477 (Insulation Leakage Current Measuring Device) to detect the effective leakage current (Ior) corresponding to the insulation resistance component due to the insulation state in the live state. . This device is briefly described as a three-phase converter, but has the configuration as shown in FIG. 8 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 grounded phase and the non-grounded phase is measured through the reference voltage input line connected to the low voltage charging section separately in the earth leakage detector 12 in the converter 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 converter (3) and the ground is very small and the capacitance (8) component is very large, the current (Io) leaked to the ground by the commercial AC voltage. Since Ioc >> Ior, the leakage current detected by the image transformer 10 is the effective leakage current (Ior) due to the very small insulation resistance (9) due to the reactive leakage current (Ioc) due to the very large capacitance (8). Measurement sensitivity of the current transformer is reduced due to the deterioration of the magnetic field characteristics of the current transformer 10, and the leakage current (Ioc) due to capacitance is not displayed because the image leakage current (Io), which is widely used in the past, is not displayed. ), It is inconvenient to provide a variety of information to the leakage manager, such as a large component can not compare whether the image leakage current (Ioc) is largely detected. In addition, Japanese Utility Model Publication No. 58-180478 (Low Voltage Converter Large Capacity Capacitance Compensation Device) in the prior art discloses the influence of the capacitance (8) component on the capacitance (8) having a value corresponding to the capacitance existing between the earths. A 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 ground fault detection device so that the corresponding leakage current of the reactive component flows in the opposite direction to the image transformer 10. Doing. 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 earth leakage detection system capable of accurately detecting the effective leakage current (Ior) at.

In addition, by providing the 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, smooth transfer management can be performed. There has been a need for an earth leakage detection system.

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 small, the effective leakage current (Ior) is accurately detected, and the image leakage current (Io) and the reactive component of the commercial frequency component flowing between the actual converter (3) and the ground An object of the present invention is to provide a ground fault detection system capable of detecting and displaying a leakage current Ioc.

In addition, the object of the present invention is to provide an earth leakage detection system capable of remotely controlling the display, alarm alarm output and input / output by calculating the insulation resistance (9) for the voltage of the commercial alternating frequency between the converter (3) and the earth.

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

An earth leakage detection system for detecting an earth leakage state of a single-phase converter in a live state according to an embodiment of the present invention for achieving the above object,

An analog / digital converter 61 having a function of converting an analog value into a digital value; A digital / analog converter 51 having a function of converting a digital value into an analog value; An analog multiplication unit 52 having a function of multiplying (or mixing) two analog components; A setting unit 63 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 64 capable of displaying various data or displaying alarms; An arithmetic control unit 62 for reading and outputting various data and having a calculation function, and a storage unit 66 having a function for storing various data;

In order to accurately detect and monitor the effective leakage current (Ior) of the insulation resistance (9) component present between the earth, even if the capacitance (8) component between the converter (3) and the earth is very large, the voltage component of the converter (3) Voltage detecting means (22a, 22b) for detecting; A voltage detector (31) for converting the voltage component detected by the voltage detectors (22a, 22b) into a constant voltage magnitude; A voltage filter unit 32 for extracting a voltage component of a commercial frequency component among the voltage components Va1 converted through the voltage detector 31; A 90 degree or more portion 33 for shifting the phase of the voltage Va2 of the commercial frequency component extracted through the voltage filter part 32 by 90 degrees; An image current transformer 10 for detecting an image leakage current flowing between the converter 3 and the ground; A current / voltage converter 41 for converting the current value of the image leakage current component detected by the secondary side of the image transformer 10 to a voltage value; An amplifying unit 42 for amplifying the image leakage current component converted into a voltage component through the current / voltage converting unit 41; A current filter unit 43 for extracting only commercial frequency components among the image leakage current components amplified by the amplifying unit 42; 90 degrees of the voltage component Va2 of the commercial frequency component taken out through the voltage filter unit 32 and the image leakage current component Io1 of the commercial frequency component taken out through the current filter unit 43 A synchronization detector 44 for phase-synchronizing the 90-degree shift voltage component Va3 converted in the upper portion 33; A reactive current compensation winding 21 having a function of an auxiliary winding by separately installing a test line of the image current transformer 10 or separately; A compensating filter unit 53 having a function of extracting a commercial frequency component and flowing a current to the reactive current compensation winding 21 of the image current transformer 10; .

According to another embodiment of the present invention for achieving the above object, a ground fault detection system for detecting a ground fault state of a single-phase converter,

An analog / digital converter 61 having a function of converting an analog value into a digital value; A digital / analog converter 51 having a function of converting a digital value into an analog value; An analog multiplication unit 52 having a function of multiplying (or mixing) two analog components; A setting unit 63 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 64 capable of displaying various data or displaying alarms; An operation control unit 62 for reading and outputting various data and having an operation function; A storage unit 66 having a function of storing various data;

Voltage detecting means (22a, 22b) for detecting the voltage component between the grounds of the converter (3); A voltage detector (31) for converting the voltage component detected by the voltage detectors (22a, 22b) into a constant voltage magnitude; A voltage filter unit 32 for extracting a voltage component of a commercial frequency component among the voltage components Va1 converted through the voltage detector 31; A 90 degree or more portion 33 for shifting the phase of the voltage Va2 of the commercial frequency component extracted through the voltage filter part 32 by 90 degrees;

An image current transformer 10 for detecting an image leakage current flowing between the converter 3 and the ground; A current / voltage converter 41 for converting the current value of the image leakage current component detected by the secondary side of the image transformer 10 to a voltage value; A current filter unit 43 for detecting only a component of a commercial frequency among the image leakage current components converted into voltage components through the current / voltage converter 41; An amplifying unit 42 for amplifying the image leakage current of the commercial frequency component detected by the current filter unit 43;

The image leakage current Io1 of the commercial frequency component amplified by the amplifying unit 42 is extracted through the voltage filter unit 32 and the voltage component Va2 of the common frequency component and the above 90 degree portion ( A synchronization detector 44 for phase-synchronous detection of the 90 degree shift voltage component Va3 converted in 33);

The reactive current compensation winding 21 having a function of the auxiliary winding by separately installing the test wire of the image current transformer 10 or the auxiliary winding, taking out commercial frequency components, and the reactive current compensation winding 21 of the image current transformer 10 described above. It is characterized in that it comprises a compensation filter unit 53 having a function of flowing a current to the.

The earth leakage detection system according to another embodiment for detecting a short circuit state of the single-phase converter in the live state of the present invention for achieving the above object,

An analog / digital converter 61 having a function of converting an analog value into a digital value; A zero cross section 54 having a function of comparing the zero cross point of the analog voltage waveform to a digital component of a square wave; A digital multiplication unit 55 having a function of multiplying (or mixing) two digital components; A waveform shaping unit 56 having a function of converting a digital waveform into an analog waveform; A setting unit 63 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 64 capable of displaying various data or displaying alarms; An operation control unit 62 for reading and outputting various data and having an operation function; A storage unit 66 having a function of storing various data;

Voltage detecting means (22a, 22b) for detecting the voltage component between the grounds of the converter (3); A voltage detector (31) for converting the voltage component detected by the voltage detectors (22a, 22b) into a constant voltage magnitude; A voltage filter unit 32 for extracting a voltage component of a commercial frequency component among the voltage components Va1 converted through the voltage detector 31; A 90 degree or more portion 33 for shifting the phase of the voltage Va2 of the commercial frequency component extracted through the voltage filter part 32 by 90 degrees;

The current transformer 10 for detecting the image leakage current flowing between the converter 3 and the ground, and the current for converting the current value of the image leakage current component detected by the secondary side of the image transformer 10 into voltage values. A voltage converter 41; An amplifying unit 42 for amplifying the image leakage current component converted into a voltage component through the current / voltage converting unit 41; A current filter unit 43 for detecting only commercial frequency components among the image leakage current components amplified by the amplifier 42;

The voltage component Va2 of the commercial frequency component extracted from the image leakage current Io1 of the commercial frequency component detected by the current filter unit 43 through the voltage filter unit 32 and the above 90 degree portion. A synchronization detector 44 for phase-synchronous detection of the 90-degree shift voltage component Va3 converted in (33);

A reactive current compensation winding 21 having a function of an auxiliary winding by separately installing a test line of the image current transformer 10 or separately; It is characterized in that it comprises a compensation filter unit 53 having a function of taking out a commercial frequency component and flowing a current in the reactive current compensation winding 21 of the image current transformer 10.

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Preferably, the effective leakage current Ior1 and the invalid leakage current Ioc1, the image leakage current component Io1, and the commercially available components extracted by phase synchronization detection by the synchronous detection unit 44, respectively. The voltage component Va2 of the frequency component and the 90-degree shift voltage component Va3 are converted into a digital value by the analog / digital converter 61 and converted by the analog / digital converter 61. The digital value and the various data stored in the storage section 66 are read by the arithmetic and control section 62, and the invalid leakage current Ioc1 extracted by the synchronous detection section 44 is the effective leakage current Ior1. When a predetermined multiple or more times is detected, the various types of data stored in the storage unit 66, the leakage current Ioc1 for the invalid portion and the leakage current Ior1 for the effective portion taken out from the synchronous detection unit 44 are detected. Ineffective leakage current (Ioc) flowing between the earth of the above-mentioned actual converter 3 using data Calculates the invalid part removal leakage current value Ioc3 which can be detected below a certain value in the image current transformer 10,

The value corresponding to the invalid component removal leakage current transmitted to the digital / analog converting unit 51 and converted by the digital / analog converting unit 51 described above. Multiply (or mix) with the 90-degree shift voltage component Va3 detected by the 90-degree or higher portion 33 in the analog multiplication unit 52 having a function of multiplying (or mixing) two analog component values. The component corresponding to the reactive leakage current multiplied (or mixed) by the analog multiplication unit 52 is extracted from the compensating filter unit 53 only the commercial frequency component to the reactive current compensation winding 21. In the state that the arithmetic control unit 62 operates in the opposite direction to the leakage current component flowing between the converter 3 and the ground so that the reactive leakage current component is detected below the predetermined value by the image current transformer 10, In the current filter unit 43 The analog / digital converting section 61 is used to convert the output image leakage current component Io2 and the effective divided leakage current component Ior2 and the invalid divided leakage current component Ioc2 detected by the synchronous detection section 44. After reading and storing in the above operation control unit 62, the effective leakage current Ior flowing between the actual converter 3 and the ground, and the image leakage current Io and the invalid leakage current Ioc before removing the invalid components. It is characterized by calculating and displaying.

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Preferably, the calculation is performed such that the reactive leakage current component of the commercial frequency detected by the synchronous detector 44 through the image current transformer 10 is smaller than a predetermined multiple of the effective leakage current component of the commercial frequency. The synchronization detector 44 in the state in which the controller 62 passes the reactive current removal leakage current calculated in the direction opposite to the reactive current leakage current of the commercial frequency to the reactive current compensation winding 21 of the image current transformer 10. The active component leakage current of the commercial frequency detected in the) to detect the effective leakage current or insulation resistance value.

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Preferably, when the leakage current value is greater than the alarm set value or the insulation resistance value is smaller than the alarm set value compared with the alarm set value set in the setting unit 63 or the alarm set value stored in the storage unit 66, the buzzer or LED is displayed on the display unit 64. It is possible to display an alarm alarm outside by using a means such as a relay.

In addition, the earth leakage detection system of the present invention preferably further includes an input / output unit 65 for telecommunication and control.

Hereinafter, the earth leakage detection system of the present invention will be described with reference to the accompanying drawings.

3 to 4 are examples in which the earth leakage detection system of the embodiment is provided in the single phase converter of the present invention, and FIGS. 5, 6, and 9 are earth leakage detection apparatuses used in the single phase converter of FIGS. An internal detailed embodiment of 12). 7 is an embodiment of a flowchart illustrating the operation of the ground fault detecting apparatus of FIGS. 5 to 6.

3, 5, and 7 which are embodiments in a single phase converter are described first.

In FIG. 3, 1 is a transformer for converting to low voltage, and supplies electric power to the converter 3 through the switchgear 2. As shown in FIG. 5 is a ground wire for connecting to ground 6 for the safety of transformer 1. In general, the grounding of the transformer is performed 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 kinds and three kinds of grounding. On the other hand, in the state where power is supplied to the load 4 through the switch 2 and the converter 3, the insulation resistance 9 and the capacitance 8 between the converter 3 including the load 4 and the ground exist. The insulation resistance 9 is directly related to the short-circuit state of the converter 3 and the load 4, and the insulation resistance 9 has a voltage component between the converter 3 and the earth and an in-phase leakage current, that is, an effective 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 or the earth leakage state. The capacitance 8 flows a voltage component between the converter 3 and the ground and a leakage current of 90 degrees out of phase, i.e. an inactive leakage current Ioc. 10 is a leakage current detection means such as an image current transformer installed to detect leakage current components flowing through the ground of the converter 3, that is, image leakage current (Io = Ior + Ioc), and the primary side passes the converter 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. In the case of monitoring the short-circuit state of the single-phase converter, the video current transformer 10 flows in the opposite direction to the leakage current flowing between the converter 3 and the ground so that the reactive leakage current by the capacitance component is detected below a certain value. In order to install a separate auxiliary winding as a conductor on the primary side, or to install a separate third winding or to use the winding for the test of the current transformer 10.

12 is a ground fault detection device for monitoring a ground fault state, which is an insulation state between the converter 3 and the ground.

In the state in which power is supplied to the converter 3 through the transformer 1, the insulation state of the converter 3 or the load 4 is followed by an insulation resistance 9 which is directly related to a short circuit between the converter 3 and the earth. The reactive leakage current Ioc caused by the capacitance 8 which is not directly related to the leakage leakage current Ior caused by the leakage current flows through the load type 3 ground (7) and the transformer type 2 ground (6). (Io) flows. 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 ground fault detection device 12.

Then, by the voltage detecting means 22a and 22b for detecting the voltage component of the converter 3 in order to distinguish between the effective leakage current Ior and the reactive leakage current Ioc from the leakage current Io. The detected commercial AC voltage component is input to the ground fault detecting device 12. A method of detecting the commercial AC voltage component will be described in more detail. As shown in Figs. 3 and 4, the voltages of the phases which are not grounded and the grounded phases are detected by the voltage detecting means 22a and 22b. An embodiment in which only one voltage detecting means 22a is used for the voltage of a phase that is not grounded by connecting the ground connecting the earth ground to the phase and the ground fault detecting device 12 may be used. In the case where the converter 3 in a special case is a non-grounded converter, two voltage detection means such as 22a and 22b can be used to detect a commercial AC voltage component of the converter 3 and a separate transformer can be used. The commercial alternating voltage component of the converter 3 can also be detected.

First, FIGS. 5 and 7, which are a first embodiment of the ground fault detecting apparatus 12, will be described in detail.

In the main flow stored in the storage unit 66 inside the ground fault detecting apparatus 12 as in the embodiment of FIG. 7, various data used in the ground fault detecting apparatus 12, such as a keypad or a switch, for example, When the ground fault detecting device 12 is installed, data such as the number address, alarm set value, frequency, phase voltage of the converter 3, amplification factor for each component, etc. for each ground fault detecting device 12 can be set. Various data setting flows 100 in the setting unit 63 having a function are executed, and then various data or external data stored in advance in the various data or storage units 66 set by the setting unit 63 described above. When the operation of the various data read flows 110 to read various data inputted through the external I / O unit 65 at a remote location is executed, and then the Va2 and Va3 read & store flows 120 are executed, FIG. Or leakage current detection number of the embodiment of the earth leakage detection system of 4. The leakage current Io detected at the stage 10 and the voltage component detected at the voltage detecting means 22a and 22b are input to the ground fault detecting apparatus 12. The voltage component detected by the voltage detecting means (22a, 22b) is devide to a voltage usable in the ground fault detecting device (12) using a resistor, a capacitor, or a transformer in the voltage detecting unit (31) and output as Va1 value. Since the voltage component Va1 is a component in which a commercial frequency component, a noise component of another component, and a commercial frequency component are mixed, only the voltage component Va2 of the commercial frequency component is taken out by the voltage filter unit 32. Inputted to the 90-degree or more portion 33 for shifting the phase of the voltage component Va2 of the commercial-frequency component taken out from the voltage filter unit 32 by 90 degrees. The phase of the voltage component Va2 is converted into a 90 degree shifted voltage component Va3 shifted by 90 degrees. The voltage component Va2 and the 90-degree shift voltage component Va3 of the commercial frequency component extracted from the voltage filter unit 32 are output to an analog / digital converter 61 for converting an analog value into a digital value. The Va2 and Va3 values are converted into digital values by the analog-to-digital converter 61, and the data of Va2 and Va3 are stored in the storage unit 66 through the operation controller 62.

 Next, when the Io1, Ioc1, and Ior1 read & store flows 130 are executed, the image leakage current component Io detected through the image transformer 10 as described above is a current / voltage conversion that converts current into voltage. The leakage current component converted into a voltage component in the section 41 and amplified in the amplifier 42 extracts only the leakage current Io1 of the commercial frequency component from the current filter section 43. The leakage current Io1 of the commercial frequency component extracted from the current filter unit 43 is also output to the analog / digital converting unit 61 and stored in the storage unit 66 through the arithmetic and control unit 62. The leakage current (Io1) component of the commercial frequency component extracted from the current filter unit 43, the voltage component Va2 of the commercial frequency component extracted from the voltage filter unit 32, and the above 90 degree portion Three components of the 90-degree shift voltage component Va3 converted in (33) are input to the synchronous detector 44 for synchronously detecting the phase. In the synchronous detector 44, the leakage current Io1 component of the commercial frequency component is controlled by the operation control unit 62, and the leakage current of the component in phase with the 90-degree shift voltage component Va3, that is, the capacitance ( 8) The leakage current Ioc1 component of the reactive leakage current Ioc component flowing through the circuit 8 is taken out and output to the analog / digital converter 61, which is then stored in the storage unit 66 through the arithmetic and control unit 62. The leakage current Io1 of the commercial frequency component is again stored under the control of the arithmetic and control unit 62, and the leakage current of the component having the same phase as the voltage component Va2 of the commercial frequency component, that is, the insulation resistance 9 The leakage current Ior1 of the effective leakage current Ior component flowing through is taken out, outputted to the analog / digital conversion section 61, and stored in the storage section 66 through the arithmetic and control section 62.

Then satisfy the condition Ioc1 <k * Ior1? When the flow 140 is executed, it is compared or not to determine whether the Ioc1 value of the reactive leakage current component stored in the storage unit 66 is greater than or less than the value obtained by multiplying the Ior1 value of the effective leakage current component by a constant constant (k). do. The above k value is a number larger than 0, but it is preferable that the value of k is different depending on the length of the cable in the installation operation state of the converter 3 or the capacitance at the input terminal of the load 4, and the like. The value 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 Ioc1 <k * Ior1 condition satisfies the flow 140 above, i.e., the Ior1 value is greater than the Ioc1 value, the flow is executed in the flow 200 for reading & storing Io2, Ioc2, Ior2, and if not satisfied, i.e., the capacitance (8) If the Ioc1 value corresponding to the reactive leakage current (Ioc) value flowing through is greater than the Ior1 value corresponding to the effective leakage current (Ior) value flowing through the insulation resistance (9), the primary winding of the image current transformer 10 described above. In order to reduce the reactive leakage current (Ioc) flowing through the circuit, 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) is calculated. The invalid calculation flow 150 is executed.

When the invalid fraction calculation flow 150 is executed, the data is executed in the various data read flow 110 and the various data stored in the memory 66 and the Va2 and Va3 read & save flow 120. Va3 value stored in the storage unit 66 and Io1, Ioc1, Ior1 read & store flow 130 are executed and the Ioc1 value and Ior1 value stored in the storage unit 66 are stored in the voltage detection unit 31 and the voltage. The amplification factor related to the detection of the commercial frequency voltage component of the filter unit 32 and the 90-degree section 33, the image transformer 10, the current / voltage converter 41, the amplifier 42, and the current filter unit (43) and the analog multiplication unit 52 and the commercial frequency component having a function of multiplying (or mixing) two or more analog components with an amplification factor related to the detection of the leakage current component of the commercial frequency component None of the commercial frequency components of the compensating filter unit 53 having the function of converting the values into extraction and current values Invalidation of the commercial frequency component by the capacitance 8 flowing between the actual converter 3 and the ground through the calculation process in the calculation control unit 62 using data such as amplification factor related to the removal of the minute leakage current component. Calculate the reactive dust removal leakage current value Ioc3 of approximately the same magnitude as the minute leakage current Ioc. The reactive component removal leakage current value Ioc3 is calculated as follows, and the definition of the constant for the amplification factor or gain used in the following calculation is as follows, and these values are set in the setting unit 63 Or values stored in the storage unit 66 in advance.

A1: Amplification-related coefficients of the voltage detector 31

A2: Amplification-related coefficients of the voltage filter unit 32

A3: Amplification-related coefficient of more than 90 degrees 33

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 section 52

C2: amplification-related coefficients of the compensating filter unit 53

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

Substituting the Ioc value of Equation 1 above into the Ioc value of Equation 2 above, Ioc3 can be obtained as described above.

Next, when the invalid fraction removing flow 160 is executed, the digital / analog converting section converts the invalid fraction removing leakage current value Ioc3 of the commercial frequency component by the capacitance 8 calculated by the operation controller 62. The value is sent to 51, and the digital-to-analog converter 51 is converted into an analog value and input to the analog multiplier 52. In the analog multiplication unit 52, the 90-degree voltage component Vf3 of the low frequency component detected by the 90-degree or higher portion 33 and the calculation controller 62 are calculated and the digital / analog converter 51 Multiplying (mixing) of the reactive component removal leakage current value Ioc3 inputted through and having a 90-degree phase difference with the voltage of the commercial frequency component between the converter 3 and the earth, and sends it to the compensation filter unit 53. In the compensation filter unit 53, the filter may be once again filtered to have the same frequency as the commercial frequency voltage between the converter 3 and the ground, and may flow in the opposite direction to the leakage current flowing between the converter 3 and the ground in the image transformer 10. The reactive leakage current component detected by the secondary side winding of the image current transformer 10 is fixed by converting it into a current value and sending it to the reactive current compensation winding 21 formed of a test line of the image current transformer 10 or a separate auxiliary winding. Try to be below the value.

Next, the Ior1 and Ioc1 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 synchronous detector 44 as described above. The effective leakage current Ior1 value and the invalid leakage current Ioc1 value are read by the operation control unit 62 through the analog / digital conversion unit 61, and the above Ioc1 < k * Ior1 conditions are satisfied. Ioc1 < k * Ior1 condition satisfaction? Flow 180 identical to the flow 140 is determined by re-execution.

As described above, when the k constant is k = 1, even if the reactive component removal flow 160 is executed, if the reactive leakage current Ioc1 is larger than the effective leakage current Ior1, that is, still leaking. If the current is continuously detected over a certain value through the image transformer 10, the invalid component correction flow 190 similar to the invalid component 150 is repeated, and then the invalid component removal flow 160 is repeated again. Run On the other hand, if the reactive leakage current (Ioc1) is smaller than the effective leakage current (Ior1) in the state where the invalid fraction removal flow 160 and Ioc1, Ior1 read & flow 170 are executed, that is, the invalid leakage current Is detected below a certain value through the image transformer 10, or the reactive leakage current Ioc1 is the effective leakage current Ior1 when the Io1, Ioc1, Ior1 read & store flow 130 is executed. If the value is smaller than the value, Io2, Ioc2, and Ior2 read & store flows 200 are executed.

If the above Io2, Ioc2, and Ior2 read & store flows 200 are executed, the current filter unit 43 uses the same frequency as the Io1, Ioc1 and Ior1 read & store flows 130 described above. The leakage current Io2 is taken out, and the synchronous detection section 44 of the effective frequency leakage current component Ior2 in phase with the commercial frequency voltage component of the voltage filter unit 32 and the above-mentioned 90 degrees or more 33 The leakage current component in the calculation control unit 62 through the analog / digital conversion unit 61 is extracted by taking out the leakage current component Ioc2 having a 90-degree phase difference between the commercial frequency voltage component and the in phase phase. The components Io2, Ioc2, and Ior2 are read and stored in the storage unit 66.

Next, when the calculation & display flow 210 is executed, various data stored in the storage unit 66 in each of the above flows are detected, for example, Va2, Va3, Io1, Ioc1, Ior1, Io2, Ioc2, Ior2, and the like. Using data and amplification factor, it can be expressed by the following formula.

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

The image leakage current Io flowing between the converter 3 and the ground can be calculated by the following equation.

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

The reactive leakage current Ioc flowing in the capacitance 8 flowing between the converter 3 and the ground can be calculated by the following expression (6).

 As described above in Equation 1 to Equation 6, 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 converter 3 and the ground can be detected and calculated as described above. The leakage current value or state may be displayed on the display unit 64 which not only displays the current Ior but also the image leakage current Io data on the display means such as FND or LCD or outputs the display means such as an LED or a buzzer. .

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

In addition, the reactive leakage current Ioc due to the capacitance flowing from the actual converter 3 to the ground by using the reactive leakage current component Ioc1 stored in the storage unit 66 after being read out to compensate for the reactive leakage current, is stored. ) Can be calculated and displayed on the display unit 64,

In addition, the display unit 64 selectively displays the various leakage current components and the insulation resistance values using the setting unit 63 having a function of inputting or selecting various data by means of a switch or a keypad. 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 unit is displayed. The alarm state can be displayed on 64, or the various data or alarm alarms calculated above can be output through the external output unit 65.

Next, Fig. 4, which is an explanatory diagram of a connection connection of a second earth leakage detection system in the single-phase converter 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, and the converter 3 after the image current transformer 10 is installed. And it is possible to detect only a short-circuit state of the load (4), in Figure 4 the transformer is installed in the middle of the ground line (5) connecting the transformer (1) and the ground (6) It is explained that the short-circuit state of all the converters 3 and the loads 4 supplied by the secondary side of (1) can be detected.

Next, FIG. 6 which is a 2nd Example of the earth leakage detection apparatus 12 for single-phase converters of this invention is demonstrated briefly.

In FIG. 5, which is the first embodiment of the ground fault detecting apparatus 12 described above, the internal structure of the ground fault detecting apparatus 12 for detecting, calculating, controlling, and displaying 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 value of the commercial frequency component is taken out. In FIG. 6, which is a second embodiment of the ground fault detecting 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 order of the positions of the amplifier 42 and the current filter 43 is changed so that the values input to the synchronous detector 44 and the analog / digital converter 61 are shown in FIG. 5. In contrast to using the output value of 43, in Fig. 6, the output value of the amplifying section 42 is used, 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. 9, which is a third embodiment of the earth leakage detecting apparatus 12 for single-phase converters of the present invention, will be briefly described.

In FIG. 5, which is the first embodiment of the earth leakage detecting apparatus 12 described above, the effective leakage current Ioc between the converter 3 and the ground is large, and thus, the current leakage current detected by the image current transformer 10 is effective. In order to solve the problem in which the minute leakage current (Ior) component detection is incorrectly detected, the calculation is made when the reactive leakage current (Ioc1) component extracted through the synchronous detector 44 is larger than a predetermined multiple of the effective leakage current (Ior1). The control unit 62 calculates the leakage leakage leakage calculated by the operation control unit 62 to flow in the direction opposite to the leakage current flowing between the converter 3 and the ground to the reactive current compensation winding 21 of the image current transformer 10 by calculation. The 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. Leakage current (Ioc1) value is before effective leakage On the other hand, the control unit is configured to be smaller than (Ior1), whereas in FIG. 9, the third embodiment, 90 degrees obtained by shifting the phase of the voltage component between the converter 3 and the ground taken out from the 90-degree section 33 by 90 degrees. The analog voltage component of the shift voltage component Va3 is converted to a 90 degree shift voltage component of the digital component which is converted into a digital value of high when the value is greater than the zero point and is converted to a low digital value when the value is smaller than the zero point. In the waveform shaping unit 56, the phase of the digital value obtained by multiplying (or mixing) the invalid part removal leakage current value Ioc3 of the digital component calculated by the operation control unit 62 with the digital multiplier 55 is 90. Compensation filter unit 53 by converting the component having the waveform of the analog component which is the same as the phase of the phase shifter 33 and whose magnitude is the value corresponding to the invalid part removal leakage current value calculated by the operation control unit 62. To output As a result, the inaccurate amount of leakage due to the capacitance reduces the inaccuracy of the detection of the effective leakage current due to the very small insulation resistance detected by the image current transformer 10 due to the capacitance flowing to the ground in the image current transformer 10. The method of detecting, calculating, and displaying the effective leakage current by the insulation resistance after flowing in the direction opposite to the reactive leakage current is not significantly different from the above-described embodiment.

The internal structure of the ground fault detection device 12 for detecting, calculating, controlling and displaying the leakage current in the above senses the leakage current component through the image current transformer 10, and converts the leakage current component into a current / voltage converter 41. Is converted to a voltage component at, and amplified by the amplification unit 42, and the amplified value is taken out from the current filter unit 43 to take out only the values of commercial frequency components. In FIG. 6, which is a second embodiment of the ground fault detecting apparatus 12, the leakage current component is detected through the image current transformer 10 and the value is converted into a voltage component by the current / voltage converter 41. After amplifying at 42, only the value of the commercial frequency component is taken out from the current filter unit 43. In other words, the order of the positions of the amplifier 42 and the current filter 43 is changed so that the values input to the synchronous detector 44 and the analog / digital converter 61 are shown in FIG. 5. In contrast to using the output value of 43, in Fig. 6, the output value of the amplifying section 42 is used, 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 The amplification-related coefficient C1 corresponding to the analog multiplier 52 of the embodiment described above is replaced by the amplification-related coefficients of the digital multiplication unit 55 and the waveform shaping unit 56.

In addition, the structure of the ground fault detecting device 12 of FIG. 5 may be installed and used in the middle of the ground line 5 of the transformer 1 as shown in FIG. 4, and the structure of the ground fault detecting device 12 of FIG. 3 can be installed and used in the middle of the converter (3), and the image current transformer 10 can be installed between the transformer (1) and the switch (2), not in the middle of the converter (3), and Can be installed and used in branch converters. In addition, in the embodiment of the present invention, the voltage detector 31 has an internal configuration of the leakage detector 12 in the converter 3 to detect the voltage phase and magnitude, but the circuit having the function of the voltage detector 31 is shorted. There may be an embodiment configured to the outside of the detection device 12, the current / voltage conversion unit 41 to the internal configuration of the earth leakage detection device 12 to detect the leakage current, but the image of the current transformer 10 When an electronic component such as a resistor is directly connected to the secondary side, there may be an embodiment in which the portion having the function of the current / voltage converter 41 of the ground fault detection device 12 is configured outside of the ground fault detection device 12. In some embodiments, an amplifier 42 having a function of the current / voltage converter 41 may be configured, and an embodiment in which the positions of the amplifier 42 and the current filter 43 of FIG. Among the voltage detection means in the above embodiment of the present invention It is apparent that 22b can be easily applied by those skilled in the art in various ways within the scope of the present invention, such as being replaced with a ground wire, without departing from the gist of the present invention.

As described above, the present invention detects the leakage current component Io flowing between the ground of the low voltage converter 3 through the image current transformer 10 and amplifies the leakage current Io through the amplifier 42. The leakage current component Io1 of the commercial frequency component may be extracted through the amplified leakage current component through the current filter unit 43, or the leakage current Io detected through the image current transformer 10 may be used. 43, only the commercial frequency component is taken out, and the extracted leakage current component is converted into the leakage current component Io1 of the commercial frequency component amplified by the amplifying unit 42, and also through the voltage detection means 22a and 22b. 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 phase-ineffective reactive leakage current Ioc1 are detected, and the detected effective 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 and the invalid value read through the analog / digital converter 61 above. The leakage current Ioc1 value of the minute is compared and the leakage current Ioc1 value of the reactive value is larger than the leakage current Ior1 value of the effective amount of the constant multiple k, that is, the leakage current Ioc by the capacitance 8 If a large amount of leakage current flows in the component, the computation control unit 62 calculates the value of the removal leakage current Ioc3 for the invalid portion by calculation. Voltage component Va3 through 90-degree phase section through analog converter 51 and an invalid component having a 90-degree phase difference from a commercial frequency alternating voltage through multiplier and compensation filter section 53 in analog multiplier 52 The leakage current (I) flows in the opposite direction to the image transformer 10 so that the leakage current Ioc1 value 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 / digital converter 61 and the operation controller 62, the effective leakage current Ior2 detected by the synchronous detector 44 can be detected accurately, so that the converter 3 Alternatively, the image current transformer 10 may have an invalid leakage current Ioc due to the capacitance 8 component present at the input of the load 4 being greater than the effective leakage current Ior due to the insulation resistance 9 component. The door that cannot accurately detect the effective leakage current (Ior) detected through the In addition, the leakage current (Ior) of the effective portion as well as the image leakage current (detected by the current filter unit 43 or the amplifier unit 42 and stored in the storage unit 66) By using the value of Io1), the image leakage current of the commercial frequency component due to the capacitance and the insulation resistance that flows from the converter 3 to the earth, which is detected and used in the conventional conventional method by the calculation by the operation control unit 62 ( Io) can also be detected and displayed, which can be compared with conventional conventional measurements. In addition, by using the voltage between the converter 3 and the ground detected by the voltage detecting means 22a and 22b, the calculation controller 62 automatically calculates the insulation resistance value R instead of the leakage current value. There is also an effect that can be 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 (7)

In a ground fault detection system for detecting a ground fault state of a single phase converter in a live state, An analog / digital converter 61 having a function of converting an analog value into a digital value; A digital / analog converter 51 having a function of converting a digital value into an analog value; An analog multiplication unit 52 having a function of multiplying (or mixing) two analog components; A setting unit 63 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 64 capable of displaying various data or displaying alarms; An operation control unit 62 for reading and outputting various data and having an operation function; A storage unit 66 having a function of storing various data; Voltage detecting means (22a, 22b) for detecting the voltage component between the grounds of the converter (3); A voltage detector (31) for converting the voltage component detected by the voltage detectors (22a, 22b) into a constant voltage magnitude; A voltage filter unit 32 for extracting a voltage component of a commercial frequency component among the voltage components Va1 converted through the voltage detector 31; A 90 degree or more portion 33 for shifting the phase of the voltage Va2 of the commercial frequency component extracted through the voltage filter part 32 by 90 degrees; An image current transformer 10 for detecting an image leakage current flowing between the converter 3 and the ground; A current / voltage converter 41 for converting the current value of the image leakage current component detected by the secondary side of the image transformer 10 to a voltage value; An amplifying unit 42 for amplifying the image leakage current component converted into a voltage component through the current / voltage converting unit 41; A current filter unit 43 for extracting only commercial frequency components among the image leakage current components amplified by the amplifying unit 42; 90 degrees of the voltage component Va2 of the commercial frequency component taken out through the voltage filter unit 32 and the image leakage current component Io1 of the commercial frequency component taken out through the current filter unit 43 A synchronization detector 44 for phase-synchronizing the 90-degree shift voltage component Va3 converted in the upper portion 33; A reactive current compensation winding 21 having a function of an auxiliary winding by separately installing a test line of the image current transformer 10 or separately; A compensating filter unit 53 having a function of extracting a commercial frequency component and flowing a current to the reactive current compensation winding 21 of the image current transformer 10; Earth leakage detection system characterized in that provided In a ground fault detection system for detecting a ground fault state of a single phase converter in a live state, An analog / digital converter 61 having a function of converting an analog value into a digital value; A digital / analog converter 51 having a function of converting a digital value into an analog value; An analog multiplication unit 52 having a function of multiplying (or mixing) two analog components; A setting unit 63 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 64 capable of displaying various data or displaying alarms; An operation control unit 62 for reading and outputting various data and having an operation function; A storage unit 66 having a function of storing various data; Voltage detecting means (22a, 22b) for detecting the voltage component between the grounds of the converter (3); A voltage detector 31 for converting the voltage component detected by the voltage detectors 22a and 22b into a constant voltage size; A voltage filter unit 32 for extracting a voltage component of a commercial frequency component among the voltage components Va1 converted through the voltage detector 31; A 90 degree or more portion 33 for shifting the phase of the voltage Va2 of the commercial frequency component extracted through the voltage filter part 32 by 90 degrees; An image current transformer 10 for detecting an image leakage current flowing between the converter 3 and the ground; A current / voltage converter 41 for converting the current value of the image leakage current component detected by the secondary side of the image transformer 10 to a voltage value; A current filter unit 43 for detecting only a component of a commercial frequency among the image leakage current components converted into voltage components through the current / voltage converter 41; An amplifying unit 42 for amplifying the image leakage current of the commercial frequency component detected by the current filter unit 43; The image leakage current Io1 of the commercial frequency component amplified by the amplifying unit 42 is extracted through the voltage filter unit 32 and the voltage component Va2 of the common frequency component and the above 90 degree portion ( A synchronization detector 44 for phase-synchronous detection of the 90 degree shift voltage component Va3 converted in 33); The reactive current compensation winding 21 having a function of the auxiliary winding by separately installing the test wire of the image current transformer 10 or the auxiliary winding, taking out commercial frequency components, and the reactive current compensation winding 21 of the image current transformer 10 described above. An earth leakage detection system, characterized in that it comprises a compensation filter unit 53 having a function of flowing a current in the In a ground fault detection system for detecting a ground fault state of a single phase converter in a live state, An analog / digital converter 61 having a function of converting an analog value into a digital value; A zero cross section 54 having a function of comparing the zero cross point of the analog voltage waveform to a digital component of a square wave; A digital multiplication unit 55 having a function of multiplying (or mixing) two digital components; A waveform shaping unit 56 having a function of converting a digital waveform into an analog waveform; A setting unit 63 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 64 capable of displaying various data or displaying alarms; An operation control unit 62 for reading and outputting various data and having an operation function; A storage unit 66 having a function of storing various data; Voltage detecting means (22a, 22b) for detecting the voltage component between the grounds of the converter (3); A voltage detector (31) for converting the voltage component detected by the voltage detectors (22a, 22b) into a constant voltage magnitude; A voltage filter unit 32 for extracting a voltage component of a commercial frequency component among the voltage components Va1 converted through the voltage detector 31; A 90 degree or more portion 33 for shifting the phase of the voltage Va2 of the commercial frequency component extracted through the voltage filter part 32 by 90 degrees; The current transformer 10 for detecting the image leakage current flowing between the converter 3 and the ground, and the current for converting the current value of the image leakage current component detected by the secondary side of the image transformer 10 into voltage values. A voltage converter 41; An amplifying unit 42 for amplifying the image leakage current component converted into a voltage component through the current / voltage converting unit 41; A current filter unit 43 for detecting only commercial frequency components among the image leakage current components amplified by the amplifier 42; The voltage component Va2 of the commercial frequency component extracted from the image leakage current Io1 of the commercial frequency component detected by the current filter unit 43 through the voltage filter unit 32 and the above 90 degree portion. A synchronization detector 44 for phase-synchronous detection of the 90-degree shift voltage component Va3 converted in (33); A reactive current compensation winding 21 having a function of an auxiliary winding by separately installing a test line of the image current transformer 10 or separately; A ground fault detection system, comprising: a compensating filter unit 53 having a function of extracting a commercial frequency component and flowing a current to the reactive current compensation winding 21 of the image current transformer 10; The method of claim 1, The leakage current Ior1 of the active part and the leakage current Ioc1 of the invalid part and the image leakage current component Io1 and the commercial frequency component of the active part extracted by phase synchronization detection by the synchronous detector 44, respectively, The voltage component Va2 and the 90-degree shift voltage component Va3 are converted into digital values by the analog / digital converter 61, and the digital values converted by the analog / digital converter 61 The various types of data stored in the storage unit 66 are read by the arithmetic and control unit 62, and the reactive leakage current Ioc1 taken out from the synchronization detector 44 is more constant than the effective leakage current Ior1. When a large amount of abnormality is detected, various types of data stored in the storage unit 66 and the invalid leakage current Ioc1 and the effective leakage current Ior1 data extracted from the synchronization detector 44 are used. The reactive leakage current Ioc flowing between the grounds of the actual converter 3 is By calculating the phase current transformer 10 minutes to remove invalid leakage current (Ioc3) that can be detected below a certain value in, The value corresponding to the invalid component removal leakage current transmitted to the digital / analog converting unit 51 and converted by the digital / analog converting unit 51 described above. Multiply (or mix) with the 90-degree shift voltage component Va3 detected by the 90-degree or higher portion 33 in the analog multiplication unit 52 having a function of multiplying (or mixing) two analog component values. The component corresponding to the reactive leakage current multiplied (or mixed) by the analog multiplication unit 52 is extracted from the compensating filter unit 53 only the commercial frequency component to the reactive current compensation winding 21. In the state that the arithmetic control unit 62 operates in the opposite direction to the leakage current component flowing between the converter 3 and the ground so that the reactive leakage current component is detected below the predetermined value by the image current transformer 10, In the current filter unit 43 The analog / digital converting section 61 is used to convert the output image leakage current component Io2 and the effective divided leakage current component Ior2 and the invalid divided leakage current component Ioc2 detected by the synchronous detector 44. After reading and storing in the above operation control unit 62, the effective leakage current Ior flowing between the actual converter 3 and the ground, and the image leakage current Io and the invalid leakage current Ioc before removing the invalid components. Earth leakage detection system, characterized in that for calculating and displaying The method according to claim 2 or 3 The arithmetic and control unit 62 such that the reactive leakage current component of the commercial frequency detected by the synchronous detector 44 through the image current transformer 10 is smaller than a predetermined multiple of the effective leakage current component of the commercial frequency. ) Is detected by the synchronous detector 44 in the state where the reactive current removal winding current calculated in the opposite direction to the reactive current leakage current of the commercial frequency flows to the reactive current compensation winding 21 of the image current transformer 10. An earth leakage detection system, characterized by detecting the effective leakage current at a commercial frequency to indicate the effective leakage current or insulation resistance value 4. The method according to any one of claims 1 to 3, If the leakage current value is greater than the alarm set value or the insulation resistance value is smaller than the alarm set value compared with the alarm set value set in the setting unit 63 or the alarm set value stored in the storage unit 66, the display unit 64 may display a buzzer, an LED or a relay. An earth leakage detection system characterized in that an alarm alarm can be displayed externally using the same means. 4. The method according to any one of claims 1 to 3, An earth leakage detection system further comprising an input / output unit 65 for remotely monitoring from the outside.

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