WO2017141328A1

WO2017141328A1 - Ground fault point locating system, control method for ground fault point locating device, and program

Info

Publication number: WO2017141328A1
Application number: PCT/JP2016/054326
Authority: WO
Inventors: 大原　久征; 秀行瀧澤; 和博小林
Original assignee: 中国電力株式会社
Priority date: 2016-02-15
Filing date: 2016-02-15
Publication date: 2017-08-24
Also published as: JPWO2017141328A1; JP6057035B1

Abstract

Provided is a ground fault point locating system for locating a ground fault point in a distribution system, said system being characterized by being provided with measurement devices that are respectively disposed at a plurality of locations in the distribution system and measure a physical quantity, which fluctuates in accordance with the power state of the distribution system, using a sensor mounted to a distribution line, and a ground fault point locating device that locates the ground fault point on the basis of the measured values of the physical quantity respectively measured by the measurement devices at the plurality of locations, and said system being further characterized in that if the measured value acquired from a measurement device has deviated from a predetermined range, the ground fault point locating device determines that the measurement device has deteriorated.

Description

Ground fault location system and control method and program for ground fault location device

The present invention relates to a ground fault location system and a ground fault location device control method and program.

When a ground fault occurs in the power distribution system, it is extremely important to quickly identify the ground fault point in order to speed up recovery from the ground fault. Therefore, a ground fault location system has been developed that captures changes in current and voltage that occur in a distribution line when a ground fault occurs and identifies a ground fault point based on changes in the current and voltage (see, for example, Patent Document 1).

JP 2004-0661142 A

This ground fault location system is used to measure the current and voltage of distribution lines, measuring equipment installed at each location of the distribution system, and the ground fault location from the measurement results sent from the measuring equipment at each location. And an entanglement point locating device.

However, since the measuring device is a device that measures the voltage and current in the live distribution line, it is difficult to check the internal sensors and electronic circuits safely unless a power failure occurs.

The present invention has been made in view of the above problems, and an object thereof is to perform an internal inspection of a measuring device used in a ground fault location system safely without power failure of the distribution line.

A ground fault location system according to one aspect is a ground fault location system for locating a ground fault point in a distribution system, wherein sensors installed at a plurality of locations in the distribution system and attached to a distribution line are provided. And measuring the physical quantity that varies according to the power state of the power distribution system, and locating the ground fault point based on the measured values of the physical quantity respectively measured by the measuring apparatus at the plurality of locations A ground fault point locating device, and the ground fault point locating device determines that the measurement device has deteriorated when the measurement value acquired from the measurement device deviates from a predetermined range.

The other problems disclosed by the present application and the solutions thereof will be clarified by the description in the column of the embodiment for carrying out the invention and the description of the drawings.

According to the present invention, it is possible to safely check the inside of the measuring device used in the ground fault location system without powering the distribution line.

It is a figure which shows the ground fault location system which concerns on this embodiment. It is a figure which shows the sensor box which concerns on this embodiment. It is a figure which shows the measuring terminal which concerns on this embodiment. It is a figure which shows the voltage table which concerns on this embodiment. It is a figure which shows the electric current table which concerns on this embodiment. It is a figure which shows the ground fault location apparatus which concerns on this embodiment. It is a figure which shows the ground fault location apparatus which concerns on this embodiment. It is a figure which shows the memory | storage device which concerns on this embodiment. It is a figure which shows the state detection table which concerns on this embodiment. It is a flowchart which shows the flow of the process which concerns on this embodiment.

At least the following matters will become clear from the description of this specification and the accompanying drawings.

FIG. 1 shows the overall configuration of a ground fault location system 1000 according to an embodiment of the present invention.

The ground fault location system 1000 is a device for locating a location where a ground fault has occurred (ground fault point P) when a ground fault occurs in the distribution system.

As shown in FIG. 1, the ground fault location system 1000 includes a measurement device 10 and a ground fault location device 300.

The measuring device 10 is a device that measures a physical quantity that varies depending on the power state of the distribution system, using sensors 150 that are installed at a plurality of locations in the distribution system and attached to the distribution line 500. Further, the ground fault location device 300 is a device that determines the ground fault point based on the measured values of the physical quantities respectively measured by the measurement devices 10 at a plurality of locations.

The measuring device 10 includes a sensor box 100 that houses the sensor 150, and a measuring terminal 200 that transmits a measurement result of the sensor 150 to the ground fault location device 300.

The sensor 150 measures a physical quantity that varies depending on the power state of the distribution system including the current or voltage of the distribution line 500. In addition, the physical quantity measured by the sensor 150 may include a power factor and a frequency.

Although the distribution line 500 is often three-phase, only one distribution line 500 is shown in FIG. 1 for simplicity of description. Therefore, in FIG. 1, each measurement terminal 10 is described as having one sensor box 100, but as shown in FIG. 2, each phase of the distribution line 500 has a sensor box 100. Yes.

The sensor box 100 is attached to the distribution line 500, and a sensor 150 that measures a physical quantity that varies depending on the power state of the distribution system from the distribution line 500, a metal outer box 110 that covers the sensor 150, and an outer box 110, and a mounting bracket 120 for fixing the 110 to the arm metal 620 of the utility pole 600.

When the sensor box 100 is installed on the power pole 600, the sensor box 100 of each phase is fixed to the arm metal 620 on the ground first, and the whole is integrated, and the arm metal 620 is lifted to a predetermined mounting position on the pole. Then, it may be fixed to the utility pole 600 by the armrest mounting tool 610. For this reason, the installation work of the sensor box 100 can also be easily performed.

The measurement terminal 200 is a device that transmits the measurement value of the physical quantity measured by the sensor 150 of each phase of the distribution line 500 to the ground fault location device 300 via the communication path 400.

In addition, the measurement terminal 200 uses the physical quantity value (direct measurement value) of each phase of the distribution line 500 that is directly measured by the sensor 150, and the value of another physical quantity that varies depending on the power state of the distribution system (indirect). Measurement value) can be calculated and transmitted to the ground fault location device 300.

For example, the measurement terminal 200 acquires a current value (direct measurement value) of each phase of the distribution line 500 from the sensor box 100, and calculates a zero-phase current (indirect measurement value) by combining these current values. It can be transmitted to the ground fault location device 300. Alternatively, the measurement terminal 200 acquires the voltage value (direct measurement value) of each phase of the distribution line 500 from the sensor box 100, and calculates the zero-phase voltage (indirect measurement value) by combining these voltage values. It can be transmitted to the ground fault location device 300.

The configuration of the measurement terminal 200 is shown in FIG.

The measurement terminal 200 includes a GPS (Global Positioning System) reception unit 210, a sensor signal acquisition unit 220, a sensor signal synthesis unit 230, a data storage unit 240, and a data communication unit 250.

The GPS receiving unit 210 acquires the current time from the GPS satellite 2000. Then, the GPS satellite receiving unit 210 writes the current time in the data storage unit 240. In the present embodiment, the GPS satellite receiving unit 210 writes the current time in the data storage unit 240 one by one every second.

The sensor signal acquisition unit 220 acquires measurement values (direct measurement values) from the sensors 150 installed in various places of the distribution system from the respective sensor boxes 100. Then, the sensor signal acquisition unit 220 writes these measurement values in the data storage unit 240. In the present embodiment, the sensor signal acquisition unit 220 writes the measurement value acquired from the sensor box 100 every second to the data storage unit 240 in accordance with the timing at which the GPS reception unit 210 writes the current time in the data storage unit 240. .

The sensor signal synthesis unit 230 calculates an indirect measurement value using the direct measurement value acquired by the sensor signal acquisition unit 220. Then, the sensor signal synthesis unit 230 writes these indirect measurement values in the data storage unit 240. In the present embodiment, the sensor signal synthesis unit 230 calculates an indirect measurement value every second and writes it in the data storage unit 240 in accordance with the timing when the GPS reception unit 210 writes the current time in the data storage unit 240.

FIG. 4 and FIG. 5 show how the current time, direct measurement values, and indirect measurement values are recorded in the data storage unit 240.

FIG. 4 shows voltage values (directly measured values) of respective phases (referred to as A-phase, B-phase, and C-phase) of the distribution line 500 measured by the sensor 150 of the measuring device 10 installed at a place where a distribution system is present. FIG. 6 is a diagram illustrating a voltage table 241 in which zero-phase voltage values (indirect measurement values) calculated from these voltage values are recorded every second in association with current time information.

FIG. 5 shows the current values (directly measured values) of each phase of the distribution line 500 measured by the sensor 150 of the measuring device 10 installed in a place where the distribution system is present, and the zero phase calculated from these current values. It is a figure which shows the electric current table 242 which matched current value (indirect measurement value) with the present time information, and was recorded for every second.

Returning to FIG. 3, the data communication unit 250 transmits the measurement values stored in the data storage unit 240 to the ground fault location device 300 at a predetermined cycle (for example, a cycle of 5 minutes). In addition, when the data communication unit 250 receives a command (transmission command) from the ground fault location device 300, the data communication unit 250 corresponds to the command for the most recent predetermined time among the data stored in the data storage unit 240. (For example, the data for the latest 60 seconds) is transmitted to the ground fault location device 300.

Next, the ground fault location device 300 will be described. The ground fault point locating device 300 is a device for locating the ground fault point P based on the respective measured values measured by the measuring devices 10 installed at a plurality of locations in the distribution system.

As illustrated in FIG. 6, the ground fault location device 300 includes a ground fault location unit 310 and a state monitoring unit 320.

The ground fault location unit 310 uses the measurement values (data recorded in the voltage table 241 and the current table 242) respectively measured by the measurement devices 10 installed at a plurality of locations in the distribution system. Receiving from the data communication unit 250, the ground fault point P is determined.

Various methods have been developed as a method for locating the ground fault point P. For example, the ground fault locating device 300 is based on the zero-phase current and the zero-phase voltage transmitted from the measurement terminals 200 in each region. By specifying the arrival time of the surge current and surge voltage in the measurement terminal 200, the ground fault point P is determined.

The state monitoring unit 320 transmits the measurement values (data recorded in the voltage table 241 and the current table 242) respectively measured by the measurement devices 10 installed at a plurality of locations in the distribution system to the data communication of each measurement terminal 200. When the measured value received from the unit 250 deviates from the predetermined range, it is determined that the measuring device 10 has deteriorated. Specifically, the state monitoring unit 320 determines the deterioration state of the measurement device 10 according to the result of comparison between the received measurement value and a predetermined determination value. For example, the state monitoring unit 320 determines that the measurement device 10 is abnormal or normal.

Although details will be described later, the ground fault location device 300 according to the present embodiment in this manner allows the internal inspection of the measuring device 10 used in the ground fault location system 1000 to be performed without power failure of the distribution line 500. It can be done safely.

Also, the ground fault location apparatus 300 according to the present embodiment transmits a measurement value transmission command to the measurement terminal 200 of the measurement apparatus 10. Then, the ground fault location device 300 receives the measurement value transmitted from the measurement terminal 200 in response to the transmission command, acquires the measurement value, and compares the measurement value with a predetermined determination value. In response to this, the state of the measuring apparatus 10 is determined.

Also in such an aspect, the ground fault location device 300 according to the present embodiment can safely perform an internal inspection of the measuring device 10 used in the ground fault location system 1000 without power failure of the distribution line 500. Is possible.

In the present embodiment, the ground fault location device 300 transmits this transmission command to the measurement terminal 200 of the measurement device 10 every predetermined time (for example, every 10 days).

In this manner, the ground fault location device 300 can capture the change in the state of the power distribution system every predetermined time (every 10 days). For this reason, for example, it is possible to grasp the progress of deterioration of the electronic devices of the distribution line 500, the sensor 150, or the measurement terminal 200, and to detect a failure in advance.

In addition, when transmitting a transmission command to the measurement terminal 200, the ground fault location device 300 may be configured to transmit the transmission command to all the measurement terminals 200 every time. Only a transmission command may be transmitted. In the latter case, all the measurement devices 10 may be divided into a plurality of groups, and a transmission command may be transmitted to the measurement terminals 200 in each group in order so that each group is visited.

When transmitting a transmission command to all the measuring terminals 200 every time, it becomes possible to inspect the deterioration state of all the measuring devices 10 every time. Further, when transmitting a transmission command only to a part of the measurement terminals 200, for example, an efficient deterioration state can be obtained by intensively inspecting the deterioration state with respect to the measurement device 10 having a large influence at the time of failure Can be inspected. Moreover, when transmitting a transmission command to the measurement terminal 200 of a different group each time, it becomes possible to test | inspect the degradation state of all the measuring devices 10, reducing the burden of the ground fault point location apparatus 300. FIG.

As shown in FIG. 7, the ground fault location device 300 according to the present embodiment includes a CPU (Central （Processing Unit) 301, a memory 302, a communication circuit 303, a storage device 304, an input device 305, an output device 306, and a recording. The computer includes a medium reading device 307.

The CPU 301 is responsible for overall control of the ground fault location device 300, and reads out a control program 700 composed of codes for performing various operations according to the present embodiment stored in the storage device 304 to the memory 302. By executing, various functions as the ground fault location device 300 are realized.

For example, the control program 700 is executed by the CPU 301 and cooperates with hardware devices such as the memory 302, the communication circuit 303, and the storage device 304, so that the ground fault location unit 310 and the state monitoring unit 320 shown in FIG. Is realized.

The memory 302 can be constituted by a semiconductor memory device, for example.

The communication circuit 303 is a network interface such as a network card. The communication circuit 303 receives data from another computer via a network such as the Internet or a LAN (Local Area Network), and stores the received data in the storage device 304 or the memory 302. The communication circuit 303 transmits data stored in the storage device 304 or the memory 302 to another computer via the network.

Of course, the communication circuit 303 also controls the exchange of various measurement values and various commands with the measurement terminal 200 performed via the communication path 400.

Note that the communication path 400 is realized by the Internet network, telephone line network, or dedicated line network, and may be wired or wireless.

The input device 305 is a device such as an operation switch, a keyboard, a mouse, or a microphone, and is a device for receiving input of information by an operator of the ground fault location device 300. The output device 306 is a device for outputting information, such as an LCD (Liquid Crystal Display), a display lamp, various display meters, a printer, and a speaker.

The storage device 304 can be configured by, for example, a hard disk device or a semiconductor storage device. The storage device 304 is a device that provides a storage area for storing various programs, data, tables, and the like. FIG. 8 shows a state where the control program 700 and the state detection table 710 are stored in the storage device 304.

The control program 700 and the state detection table 710 are read from the recording medium (various optical disks, magnetic disks, semiconductor memories, etc.) 800 to the storage device 304 by using the recording medium reader 307, so that the ground fault location device. It is also possible to store in the ground fault location device 300 by obtaining from the input device 305 or from another computer that is communicably connected via the communication circuit 303. It can also be done.

The state detection table 710 is a table used when the ground fault location device 300 determines the deterioration state of the measuring device 10, and is to be compared with measured values acquired from the measuring device 10 every predetermined time (for example, every 10 days). The judgment value is recorded.

FIG. 9 shows a state detection table 710 according to this embodiment. In FIG. 9, twelve determination conditions (1) to (12) are listed. Of course, these are merely examples for explaining the present embodiment, and other determination conditions are included. These determination conditions may not be included.

As shown in FIG. 9, the state detection table 710 includes a “determination condition” column and a “determination result” column.

In the “determination condition” column, a determination value to be compared with a measurement value acquired from the measurement apparatus 10 every predetermined time (for example, every 10 days) is recorded.

In the “determination result” column, the determination result when the ground fault location device 300 matches the determination condition as a result of comparing the measured value and the determination value is described.

For example, in the example shown in FIG. 9, when the voltage value of the A phase (direct measurement value) is compared with a predetermined upper limit value as shown in the determination condition (1), the voltage value exceeds the upper limit value. The ground fault location device 300 determines that the A-phase sensor 150 is abnormal as a deterioration state of the measuring device 10.

In addition, when the voltage value of the A phase is below the lower limit as in the determination condition (2) of FIG. 9, the possibility that the A phase of the distribution line 500 is grounded and the A phase sensor 150 is broken. Therefore, at this point in time, the ground fault location device 300 determines that the state of the measuring device 10 is an A-phase voltage abnormality.

In this case, the ground fault location device 300 determines whether the phase A of the distribution line 500 has a ground fault or the sensor 150 of the phase A has failed by considering the determination result for the other measurement devices 10. Can do. For example, if the voltage value of the A phase of the other measuring device 10 is also below the lower limit value, it can be determined that the A phase has a ground fault, and the A phase of the other measuring device 10 can be determined. If the voltage value is not below the lower limit value, it can be determined that the sensor 150 has failed.

Further, as shown in the determination condition (8) in FIG. 9, the ground fault location device 300 does not apply to the determination conditions (1) to (6) (all the direct measurement values are within the allowable range). First, when the zero-phase voltage (indirect measurement value) of the determination condition (7) exceeds the upper limit value (not within the allowable range), the sensor signal synthesis unit 230 that calculates the indirect measurement value using the direct measurement value. Can be determined to be abnormal.

As described above, the ground fault location device 300 according to the present embodiment determines the measurement device 10 according to the result of comparison with the determination value for the direct measurement value and the result of comparison with the determination value for the indirect measurement value. It is also possible to determine the deterioration state of. By such an aspect, it is also possible to find an abnormality in a device such as an electronic circuit inside the measuring apparatus 10.

Further, as shown in the determination condition (9) of FIG. 9, the ground fault location device 300 compares the result of comparison with the direct measurement value of the determination condition (2) and the result of comparison with the indirect measurement value of the determination condition (7). Depending on the above, it is possible to determine the deterioration state of the measuring apparatus 10.

Specifically, in the ground fault location device 300, when the determination condition (9) in FIG. Since the absolute value of (indirect measurement value) exceeds the upper limit value, it can be determined that the A phase is grounded.

Thus, by combining the result of comparison with the determination value for the direct measurement value and the result of comparison with the determination value for the indirect measurement value, the ground fault location device 300 according to the present embodiment is more reliable. It is also possible to discover the presence or absence of abnormalities.

Further, as shown in the determination condition (12) of FIG. 9, the ground fault location device 300 cannot correctly read the date and time from the voltage table 241 or the current table 242, or cannot identify the date and time from the read information. Can estimate that the GPS receiving unit 210 has not correctly obtained the current time from the GPS satellite 2000, and can determine that the GPS receiving unit 210 is abnormal as a deterioration state of the measuring device 10.

Although not shown in FIG. 9, for example, when no data can be read from the voltage table 241 or the current table 242, the ground fault location device 300 has an abnormality in the data storage unit 240. It can also be determined that the user is doing.

Once the measuring device 10 is installed on the armor 620 of the utility pole 600 of the distribution line 500, it continues to operate in units of several decades thereafter, but as described above, the internal inspection of the measuring device 10 is in the vicinity. It is difficult from the viewpoint of safety unless a power failure occurs. This is even more acute the higher the distribution line 500 is.

Therefore, as in the present embodiment, according to the result of comparison between the measurement value transmitted from the measurement device 10 to the ground fault location device 300 every predetermined time (for example, every 5 minutes described above) and the predetermined determination value. By determining the deterioration state of the measuring device 10, it is possible to detect an abnormality in the measuring device 10 without causing the power distribution line 500 to fail.

Alternatively, a measurement value transmission command is transmitted from the ground fault location device 300 to the measurement device 10 every predetermined time (for example, every 10 days or every month described above), and the measurement device according to the transmission command. The measuring device can be determined without causing the power distribution line 500 to be interrupted by determining the state of the measuring device 10 according to the result of the comparison between the measured value transmitted from 10 and the predetermined determination value. Ten abnormalities can be detected.

These effects become more prominent when, for example, the ground fault location system 1000 according to the present embodiment is applied to a 22 kV extra high voltage distribution system.

Next, the processing flow of the ground fault location device 300 according to the present embodiment will be described with reference to FIG.

First, the ground fault location device 300 stands by until a predetermined time arrives (S1000). The predetermined time is determined, for example, every 5 minutes or every 10 days, every month, as in the example described above.

When the predetermined time arrives, the ground fault location device 300 acquires a measurement value from the measurement device 10 (S1010). Here, the measurement value acquired by the ground fault location device 300 from the measurement device 10 may include an indirect measurement value in addition to the direct measurement value as described above.

Then, the ground fault location device 300 refers to the state detection table 710 and compares the acquired measurement value with a predetermined determination value. And the ground fault location apparatus 300 determines the deterioration state of the measuring apparatus 10 according to the comparison result (S1020).

The ground fault location device 300 outputs the determination result to the output device 306. The ground fault location device 300 can also visually display the determination result on, for example, a predetermined LCD (Liquid Crystal Display). If an abnormality is detected in the measuring device 10, the speaker is blown. You can also

In such a manner, the ground fault location device 300 can quickly transmit the deterioration state of the measuring device 10 to the operator of the ground fault location system 1000 or an operator such as a maintenance staff. When an abnormality is found in the measuring device 10 or when it is found that the measuring device 10 has been deteriorated, the operator can either replace the measuring device 10 or develop a replacement plan. It is also possible to start.

As described above, the ground fault location system 1000, the control method of the ground fault location device 100, and the control program 700 according to the present embodiment have been described. However, according to the present embodiment, the measurement device used in the ground fault location system 1000 is described. 10 can be safely inspected without power failure of the distribution line 500.

The above-described embodiment is for facilitating understanding of the present invention, and is not intended to limit the present invention. The present invention can be changed and improved without departing from the gist thereof, and equivalents thereof are also included in the present invention.

DESCRIPTION OF SYMBOLS 10 Measuring apparatus 100 Sensor box 110 Outer box 120 Pillar fitting 150 Sensor 200 Measuring terminal 210 GPS receiving part 220 Sensor signal acquisition part 230 Sensor signal synthetic | combination part 240 Data storage part 241 Voltage table 242 Current table 250 Data communication part 300 Ground fault point Orientation device 301 CPU
302 Memory 303 Communication circuit 304 Storage device 305 Input device 306 Output device 307 Recording medium reader 310 Ground fault location unit 320 Status monitoring unit 400 Communication path 500 Power distribution line 600 Power pole 610 Armor fitting 620 Armor 700 Control program 710 State Detection table 800 Recording medium 1000 Ground fault location system 2000 GPS satellite

Claims

A ground fault location system for locating ground faults in a distribution system,
A measuring device that is installed at each of a plurality of locations in the power distribution system and measures a physical quantity that varies according to the power state of the power distribution system using sensors attached to the power distribution line;
A ground fault point locating device for locating the ground fault point based on the measured values of the physical quantities respectively measured by the measurement devices of the plurality of locations;
With
The ground fault point locating device determines that the measuring device has deteriorated when the measured value acquired from the measuring device deviates from a predetermined range.
The ground fault location system according to claim 1,
The ground fault location device acquires the measurement value by transmitting the measurement value transmission command to the measurement device and receiving the measurement value transmitted from the measurement device in response to the transmission command. A ground fault location system characterized by
The ground fault location system according to claim 1 or 2,
The measurement value acquired by the ground fault location device includes a direct measurement value directly measured by the sensor and an indirect measurement value calculated by the measurement device using the direct measurement value,
The ground fault point locating device is a deterioration state of the measuring device according to a result of comparison between the direct measurement value and a predetermined determination value and a result of comparison between the indirect measurement value and a predetermined determination value. A ground fault location system characterized by determining
The ground fault location system according to claim 3,
The directly measured value includes a current value of each phase of the distribution line,
The ground fault location system, wherein the indirect measurement value includes a zero-phase current value of the distribution line.
The ground fault location system according to claim 3 or 4,
The directly measured value includes a voltage value of each phase of the distribution line,
The ground fault location system characterized in that the indirect measurement value includes a zero-phase voltage value of the distribution line.
A ground fault location system according to any one of claims 3 to 5,
When the direct measurement value is within a predetermined allowable range and the indirect measurement value is not within the predetermined allowable range, the ground fault point locating device has a circuit for calculating the indirect measurement value included in the measurement device. A ground fault location system characterized in that it is determined to be abnormal.
A ground fault location system according to any one of claims 1 to 6,
The ground distribution point locating system, wherein the distribution system is a 22 kV special high voltage distribution system.
A ground fault location system according to any one of claims 1 to 8,
The ground fault location system, wherein the measuring device is attached to a brace of a utility pole.
A measuring device that is installed at each of a plurality of locations in a power distribution system and that measures a physical quantity that varies according to the power state of the power distribution system using sensors attached to the power distribution line, and the measurement devices at the plurality of locations. A ground fault point locating device for locating the ground fault point based on the measured values of the measured physical quantities, respectively, and a control method of the ground fault point locating device in a ground fault point locating system,
The ground fault location device acquires the measurement value from the measurement device,
The ground fault point locating apparatus determines that the measurement apparatus has deteriorated when the measured value deviates from a predetermined range.
A measuring device that is installed at each of a plurality of locations in a power distribution system and that measures a physical quantity that varies according to the power state of the power distribution system using sensors attached to the power distribution line, and the measurement devices at the plurality of locations. A ground fault point locating device comprising a computer for locating the ground fault point based on the measured values of the measured physical quantities, respectively.
A procedure for obtaining the measurement value from the measurement device;
A procedure for determining that the measurement device has deteriorated when the measurement value deviates from a predetermined range;
A program for running