WO2015045075A1

WO2015045075A1 - Disconnection detection device, determination device, and disconnection detection system

Info

Publication number: WO2015045075A1
Application number: PCT/JP2013/076138
Authority: WO
Inventors: 板屋　伸彦; 洪作松村; 高野　富裕; 聖一北村
Original assignee: 三菱電機株式会社
Priority date: 2013-09-26
Filing date: 2013-09-26
Publication date: 2015-04-02

Abstract

To achieve a disconnection detection device having a reduced cost compared to conventional systems, a disconnection detection device (1) according to the present invention is provided with a disconnection detection unit (11) for detecting, in a power distribution system, a power distribution line disconnection not detected by a ground fault detection relay (21) inside a power distribution substation, and a disconnection incident notification unit (12) for causing the ground fault detection relay (21) to recognize the occurrence of an incident if the disconnection detection unit (11) detects a disconnection by causing a ground fault in a second power distribution line different from a first power distribution line in which the disconnection was detected.

Description

Disconnection detection device, determination device, and disconnection detection system

The present invention relates to a disconnection detection device, a determination device, and a disconnection detection system for detecting disconnection of a distribution line.

As a conventional device for detecting disconnection of a distribution line, there is a disconnection detection device described in Patent Document 1. This disconnection detection device includes a plurality of sensors that detect voltage and current, and a disconnection determination device that determines the presence or absence of disconnection based on the voltage measured by each sensor. The sensor is installed at a predetermined position of the distribution line, and the disconnection detection device detects disconnection based on the measurement result acquired from each sensor via the communication line.

JP 2004-233255 A

In the disconnection detection device described in Patent Document 1, it is necessary for each sensor to communicate with the disconnection determination device. That is, since each device (sensor, disconnection determination device) requires a configuration for performing communication, a cost is required for realization. When a dedicated communication network is used, maintenance is required, and when an existing public communication network is used, communication costs are incurred.

The present invention has been made in view of the above, and an object of the present invention is to obtain a disconnection detection device, a determination device, and a disconnection detection system that are less costly than conventional ones.

In order to solve the above-described problems and achieve the object, the present invention provides a disconnection detection unit that detects a disconnection of a distribution line that is not detected by a ground fault detection relay in a substation, and a disconnection in the disconnection detection unit. A disconnection accident notification unit that causes the ground fault detection relay to recognize the occurrence of an accident by causing a ground fault to occur in the second distribution line that is different from the first distribution line in which the disconnection is detected. It is characterized by.

According to the present invention, there is an effect that it is possible to realize a disconnection detecting device that detects a disconnection accident and notifies a substation at a low cost.

FIG. 1 is a diagram showing an example of a power distribution system to which the disconnection detecting device according to the present invention is applied. FIG. 2 is a diagram illustrating a configuration example of a disconnection detection device and a distribution substation. FIG. 3 is a diagram illustrating an implementation example of the disconnection detection device. FIG. 4 is a flowchart illustrating an example of a disconnection accident detection operation in the disconnection detection device. FIG. 5 is a flowchart illustrating an example of an operation in which the disconnection detection device notifies the distribution substation of detection of disconnection. FIG. 6 is a flowchart illustrating an example of a method for identifying a disconnection accident occurrence place in a distribution substation. FIG. 7 is a flowchart illustrating an example of an operation in which the disconnection detection device according to the embodiment notifies the distribution substation of the detection of the disconnection. FIG. 8 is a flowchart showing an example of a method for identifying the location of the disconnection accident at the distribution substation. FIG. 9 is a flowchart illustrating an example of an operation in which the disconnection detection device according to the embodiment notifies the distribution substation of the detection of the disconnection.

Hereinafter, embodiments of the disconnection detection device, determination device, and disconnection detection system according to the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment 1 FIG.
FIG. 1 is a diagram showing an example of a power distribution system to which the disconnection detecting device according to the present invention is applied. The disconnection detection device 1 is installed at a plurality of predetermined locations on the power distribution path from the power distribution substation 2 to the customer. In the example of FIG. 1, the disconnection detection device 1 may be installed at a ratio of one unit to several utility poles.

FIG. 2 is a diagram illustrating a configuration example of the disconnection detection device 1 and the distribution substation 2. The disconnection detection device 1 includes a disconnection detection unit 11 that detects disconnection of a distribution line, and a disconnection accident notification unit 12 that notifies the distribution substation 2 of a disconnection detected by the disconnection detection unit 11. ing. The disconnection accident notifying unit 12 includes a switch for forcibly grounding each distribution line of the A phase, the B phase, and the C phase. The distribution substation 2 includes a ground fault detection relay 21 that detects a ground fault of the distribution line, and a circuit breaker 22 that shuts off power supply to the customer side when a ground fault is detected by the ground fault detection relay 21. And a transformer 23 that transforms the electric power supplied from the host (power station side). When a ground fault occurs due to disconnection of the distribution line or occurrence of dielectric breakdown in the pole transformer, an abnormal current flows. Therefore, when the abnormal current flows, the ground fault detection relay 21 determines that a ground fault occurs. The circuit breaker 22 is controlled to stop power feeding. However, the state where the distribution line is simply cut and does not reach the ground fault, that is, the distribution line is disconnected but does not reach the ground fault for some reason (for example, the cut surface of the disconnected distribution line reaches the ground) In this case, no abnormal current flows, and the ground fault detection relay 21 cannot detect an accident. In order to deal with such a case, the disconnection detection device 1 is installed in various places of the power distribution system.

In the following description, when “disconnected” is described, it means “disconnected without ground fault”. In addition, when “ground fault” is described, it means “a state in which one or more distribution lines are grounded due to disconnection or the like”.

In the disconnection detection device 1, the disconnection detection unit 11 monitors whether or not a disconnection has occurred in each of the distribution lines of the A phase, the B phase, and the C phase. Although the disconnection detection method is not particularly defined, for example, the disconnection can be detected by monitoring the voltage between the phases. For example, when the voltage between the A phase and the B phase and the voltage between the A phase and the C phase are lower than the voltage between the B phase and the C phase, it is determined that the A phase distribution line is disconnected. When the disconnection detection unit 11 detects a disconnection, the disconnection detection unit 11 issues an instruction by outputting a closing signal to the switch of the disconnection accident notification unit 12 to forcibly ground the distribution lines of the phases that are not disconnected. For example, if phase A is disconnected, B phase forced ground fault is instructed; if phase B is disconnected, phase C forced ground fault is indicated; if phase C is disconnected, phase A forced ground fault is indicated. Instruct. When receiving an instruction from the disconnection detecting unit 11, the disconnection accident notifying unit 12 closes the switch corresponding to the instruction content, and forcibly causes the distribution line of the instructed phase to ground. As a result, even when a disconnection of the distribution line occurs, the ground fault detection relay 21 of the distribution substation 2 can detect the occurrence of the accident, and the occurrence of a disaster such as an electric shock by stopping the power supply to the disconnection occurrence point. Can be prevented.

FIG. 3 is a diagram illustrating an implementation example of the disconnection detection device. The disconnection detection device 1a shown in FIG. 3 includes a disconnection detection unit 11a that detects a disconnection by monitoring the voltage between the R phase and the T phase after being transformed by the pole transformer, and a disconnection accident notification unit 12a. I have. The disconnection detection unit 11a determines that a disconnection has occurred when the monitored voltage decreases. In the example of FIG. 3, the pole transformer is configured to transform the voltage between the A phase and the B phase, and the disconnection accident notifying unit 12a determines the C phase when the disconnection detecting unit 11a detects the disconnection. Make a ground fault.

As described above, the disconnection detection device according to the present embodiment forcibly grounds a disconnected distribution line when the disconnection detection unit 11 detects the disconnection of the distribution line and the disconnection detection unit 11 detects the disconnection. Thus, the disconnection accident notifying unit 12 that notifies the distribution substation 2 of the occurrence of the disconnection is provided. Thereby, it is possible to reliably notify the distribution substation 2 of the occurrence of a disconnection accident that cannot be detected by monitoring the abnormal current. In addition, since the occurrence of an accident is notified by forcibly grounding the distribution line, there is no need to provide a separate communication means, and a highly reliable distribution system can be realized with a minimum cost increase. .

Embodiment 2. FIG.
In the present embodiment, a disconnection accident notification method to the distribution substation 2 by the disconnection detection device 1 described in the first embodiment will be described in detail. The overall configuration of the power distribution system and the configuration of each device are the same as those in the first embodiment (see FIGS. 1 and 2).

FIG. 4 is a flowchart showing an example of a disconnection accident detection operation in the disconnection detection device 1. As shown in FIG. 4, the disconnection detection device 1 confirms the presence or absence of disconnection of the distribution line at a predetermined time (for example, 0.1 second) cycle. Specifically, it is monitored whether or not a predetermined time has passed (step S11). When the predetermined time has passed (step S11: Yes), the possibility of disconnection is determined for each of the A phase, the B phase, and the C phase. (Step S12). For example, as described in the first embodiment, the voltages between phases (the voltage between the A and B phases, the voltage between the A and C phases, and the voltage between the B and C phases) are compared. It is judged that there is a possibility. In the first embodiment, if the voltage between phases is not uniform even for a moment, it is determined that the circuit is disconnected. However, in this embodiment, there is a possibility that the voltage may fluctuate instantaneously due to a factor other than the disconnection. When uniformity is detected, it is first determined that there is a possibility of disconnection.

If there is a possibility of disconnection (step S13: Yes), a disconnection detection timer is added (step S14). That is, the elapsed time after detecting the disconnection is calculated. Next, it is confirmed whether or not the value of the disconnection detection timer is a certain value (for example, 5 seconds) or more (step S16). If it is over a certain time (step S16: Yes), it is determined that there is a disconnection, (Hereinafter referred to as the disconnection phase) is recorded (step S17). When the value of the disconnection detection timer is less than a certain value (step S16: No), the process returns to step S11 and continues the operation.

If it is determined in step S12 that there is no possibility of disconnection (step S13: No), the disconnection detection timer is reset (step S15), and the operation returns to step S11 to continue the operation.

Although the description in FIG. 4 is omitted, after the disconnection phase is recorded in step S17, the phase previously associated with the recorded disconnection phase (phase in which no disconnection has occurred) is forcibly grounded. The disconnection phase recorded in step S17 is recorded until it is manually reset by the operator after the disconnection accident is removed.

When the disconnection detection device 1 detects a disconnection, for example, according to the procedure shown in FIG. 5, a phase in which no disconnection has occurred is forcibly grounded. FIG. 5 is a flowchart illustrating an example of an operation in which the disconnection detection device 1 notifies the distribution substation 2 of detection of disconnection.

The disconnection detection device 1 monitors whether or not a predetermined time (for example, 0.1 second) has elapsed (step S21). When the predetermined time has elapsed (step S21: Yes), the disconnection detection device 1 It is confirmed whether or not the system is in an energized state (charged state) (step S22). When it is not in the charged state (step S22: No), the process returns to step S21 and continues the operation.

In the charged state (step S22: Yes), it is confirmed whether or not a disconnection phase is recorded, that is, whether or not a disconnection is detected in the operation shown in FIG. 4 (step S23). When the disconnection phase is not recorded (step S23: No), the process returns to step S21 to continue the operation. When the disconnection phase is recorded (step S23: Yes), it is confirmed whether it is during a forced ground fault (step S24). If a forced ground fault is occurring (step S24: Yes), after waiting for a certain time (for example, 2 seconds), the forced ground fault is canceled. That is, the switch of the disconnection accident notification unit 12 (see FIG. 2) is opened (steps S27 and S28). After executing step S28, the process returns to step S21 to continue the operation. Note that the standby time in step S27 is longer than the time required for detecting a ground fault in the distribution substation 2 and shutting off the power supply. The ground fault detection relay 21 (see FIG. 2) of the distribution substation 2 generally opens the circuit breaker 22 when about 1 second has elapsed since the ground fault was detected. Therefore, the standby time may be set to about 2 seconds. Instead of waiting for a certain time in step S27, the switch may be opened when a power failure occurs (when the circuit breaker 22 of the distribution substation 2 is opened and the power supply is stopped).

On the other hand, when it is not during the forced ground fault (step S24: No), waiting for the specific forced ground fault start waiting time (T seconds) for each disconnection detecting device 1 in the system, and when T seconds have elapsed, A phase different from the disconnected phase is forcibly grounded (the switch of the disconnection accident notification unit 12 is turned on) (steps S25 and S26). After executing Step S26, the process returns to Step S21 and continues the operation.

Here, a method for setting the forced ground fault start waiting time (T seconds) will be described. As shown in FIG. 1, a plurality of disconnection detectors 1 are installed in the power distribution system. Then, by setting different forced ground fault start waiting times (T seconds) for the plurality of disconnection detection devices 1, the distribution substation 2 can know where the disconnection accident has occurred. The reason will be explained.

In the distribution substation 2, when a ground fault is detected, the ground fault detection relay 21 opens the circuit breaker 22 and temporarily stops the power supply, and then restarts the power supply when a certain time has elapsed. To do. When the power supply is resumed, not all areas are energized at once, but are divided into a plurality of blocks. For example, every 10 seconds, the energization resume area is sequentially expanded by one block. In this case, the above T seconds of the disconnection detecting device 1 in the same block are set to be less than 10 seconds. For example, the forced ground fault start waiting time T of the plurality of disconnection detection devices 1 in the same block is set to T = 1 sec, 1.5 sec, 2 sec, 2.5 sec,. As a result, when the distribution substation 2 detects the ground fault again after resuming energization to a certain block, it can be seen that a disconnection accident has occurred in this block, and the ground has been resumed after resuming energization. It is possible to identify the disconnection detection device 1 that has detected the disconnection accident from the time required until the fault is detected again. Thus, by setting a different value for each device as the T, it is possible to notify the distribution substation 2 of the occurrence location of the disconnection accident. In the distribution substation 2, for example, the ground fault detection relay 21 specifies the disconnection detection device 1 that detects the disconnection accident. You may make it pinpoint other than the ground fault detection relay 21. FIG. When the number of disconnection detection devices 1 set in the power distribution system is small, the power supply area may be restarted all at once without dividing the power supply area into a plurality of blocks (for each disconnection detection device 1). Set different forced ground fault start waiting times T).

A method for identifying the location where the disconnection accident occurs in the distribution substation 2 (disconnection detection device 1 that detects the disconnection accident) will be described with reference to FIG. FIG. 6 is a flowchart showing an example of a method for identifying the location where the disconnection accident occurs in the distribution substation 2. The description will be made assuming that the ground fault detection relay 21 identifies the location where the disconnection accident occurs.

As a precondition, when the power supply is resumed, the power distribution system divides the area into a plurality of blocks, and expands the energized range by one block every X seconds. That is, when resuming power supply, first, the circuit breaker 22 is turned on to resume energization of the first block. Thereafter, the energization range is expanded by one block every time X seconds elapse. Assume that the forced ground fault start waiting time T of the disconnection detecting device 1 in each block is T = 1 sec, 2 sec, 3 sec,... (Where T <X).

The ground fault detection relay 21 of the distribution substation 2 opens the circuit breaker 22 when a ground fault is detected, and then reopens (recloses) the circuit breaker 22 when a predetermined time elapses. Then, measurement of the elapsed time is started (steps S51 and S52). Thereafter, the occurrence of ground fault is monitored (step S53), and when the occurrence of ground fault is detected (step S53: Yes), an elapsed time T1 from the execution of step S51 is calculated (step S54). Next, a ground fault section (a block in which a ground fault has occurred) is specified (step S55). Specifically, the ground fault section number is obtained by adding 1 to the integer part obtained by dividing T1 by X. For example, when X = 10 and T1 = 35, the ground fault section number = 4. This ground fault section number indicates the block in which energization has been started fourth, and a ground fault occurrence location exists in the block. When the identification of the ground fault section is completed, next, information on the ground fault generating device, that is, the disconnection detecting device 1 that detects the disconnection and forcibly generates the ground fault is calculated (step S56). Specifically, a remainder obtained by dividing T2 by X is set as information T2 of the ground fault generator. Next, a ground fault generator is specified based on the information T2. Specifically, it is confirmed whether 1 ≦ T2 is satisfied (step S57). If 1 ≦ T2 is satisfied (step S57: Yes), T (forced ground fault start waiting time) matches T2. It is determined that the disconnection detecting device 1 is a ground fault generating device (step S58). On the other hand, if 1 ≦ T2 is not satisfied (step S57: No), it is determined that there is a ground fault (an accident that is not forcibly caused by the disconnection detection device 1) (step S59).

In addition, although description is abbreviate | omitted in FIG. 6, when a ground fault is detected by step S53, the process which open | releases the circuit breaker 22 is performed in parallel with the process after step S53.

As described above, the disconnection detection device 1 according to the present embodiment determines that a disconnection has occurred when a state in which a disconnection is suspected continues for a certain period of time, for example, the interphase voltage becomes non-uniform. Thereby, the detection accuracy of disconnection can be improved. In addition, after detecting the disconnection (after recording the disconnection phase), when a forced ground fault start waiting time T having a value different from that of the other disconnection detection devices 1 in the block where energization is started at the same timing has elapsed. The phase other than the disconnection phase was forcibly grounded. Thereby, the occurrence location of the disconnection accident can be specified on the distribution substation 2 side.

Embodiment 3 FIG.
In the second embodiment, the disconnection detection device 1 sets the waiting time (forced ground fault start waiting time T) from when the disconnection is detected until the forced ground fault is performed to a value unique to the device, thereby causing a disconnection accident. In the same way, when the operation shown in FIG. 7 is executed in place of FIG. 5 described in the second embodiment, the disconnection accident can be identified. The place of occurrence can be specified on the distribution substation 2 side. FIG. 7 is a flowchart illustrating an example of an operation in which the disconnection detection device 1 according to the third embodiment notifies the distribution substation 2 of detection of disconnection. Steps S21 to S23 shown in FIG. 7 are the same processes as steps S21 to S23 shown in FIG.

When the disconnection phase is recorded (step S23: Yes), the disconnection detection device 1 of the present embodiment is different from the disconnection phase in the period, time width, and number of times unique to each disconnection detection device 1 in the system. The phase is repeatedly grounded (step S31). That is, the switch of the disconnection accident notification unit 12 is periodically opened and closed at a timing different from that of the other disconnection detection devices 1 in the system. Here, “cycle” indicates the occurrence period of forced ground fault, “time width” indicates the duration of forced ground fault, and “number of times” indicates the number of repeated occurrences of forced ground fault. It suffices that at least one of the period, the time width, and the number of times is different from that of the other disconnection detection devices 1. However, the switch is opened and closed at a timing when the circuit breaker 22 of the distribution substation 2 is not opened. For example, when the cycle is 100 msec, the time width is 40 ms, and the number of times is 10, the disconnection detection unit 11 of the disconnection detection device 1 is a distribution line of a phase that is not disconnected among the switches in the disconnection accident notification unit 12. The operation of opening the switch connected to is opened for 40 msec and then opened for 60 msec is repeated 10 times. By repeatedly opening and closing the switch at the timing when the circuit breaker 22 of the distribution substation 2 is not opened, either a ground fault (disconnecting accident with ground fault) or a disconnection accident (disconnecting accident without ground fault) occurred. Can be discriminated on the distribution substation 2 side.

A method for identifying the location where the disconnection accident occurs in the distribution substation 2 (disconnection detection device 1 that detects the disconnection accident) will be described with reference to FIG. FIG. 8 is a flowchart showing an example of a method for identifying the location where the disconnection accident occurs in the distribution substation 2. The description will be made assuming that the ground fault detection relay 21 identifies the location where the disconnection accident occurs.

When the ground fault detection relay 21 of the distribution substation 2 detects the occurrence of a ground fault (step S61: Yes), it records the occurrence time of the ground fault (step S62). Although the description in FIG. 8 is omitted, the ground fault detection relay 21 opens the circuit breaker 22 when the ground fault state continues for a certain time (about 1 second) after detecting the occurrence of the ground fault. To do. In this step S62, after the occurrence time of the ground fault is recorded, it is monitored whether the ground fault has been resolved until the circuit breaker 22 is opened. ) Is also recorded. Further, the occurrence time of the ground fault recorded in the past and the occurrence time of the ground fault newly recorded this time are checked to determine whether or not the ground fault has occurred periodically (step S63). When the ground fault does not occur periodically (step S63: No), the process returns to step S61 and continues the operation. If a ground fault occurs periodically (step S63: Yes), the ground fault occurrence time and resolution time recorded in the past and the ground fault occurrence time and resolution time newly recorded this time are The occurrence cycle, time width, and number of occurrences of the fault are calculated, and the ground fault generator is specified based on the calculation result (steps S64 and S65).

As described above, when the disconnection detecting device 1 of the present embodiment detects the disconnection, the forced ground fault is repeatedly generated at a timing different from that of the other disconnection detecting devices 1 in the system. Thereby, the occurrence location of the disconnection accident can be specified on the distribution substation 2 side.

Embodiment 4 FIG.
The operation described in the third embodiment, that is, the operation in which the disconnection detection device 1 notifies the distribution substation 2 of the detection of the disconnection (FIG. 7) may be the operation illustrated in FIG. FIG. 9 is a flowchart illustrating an example of an operation in which the disconnection detection device 1 according to the fourth embodiment notifies the distribution substation 2 of detection of disconnection. Steps S21 to S23 shown in FIG. 9 are the same processing as steps S21 to S23 shown in FIG. 5, and step S31 is the same processing as step S31 shown in FIG.

In step S31, the disconnection detection device 1 according to the present embodiment is forced to perform a ground fault repeatedly in a phase different from the disconnection phase with a unique period, time width, and number of times for each disconnection detection device 1 in the system. The ground fault is continued for a certain time, and then the forced ground fault is terminated (steps S41 to S43). That is, after step S31 is performed and the occurrence location of the disconnection accident is specified on the distribution substation 2 side, steps S41 and S42 are performed to open the circuit breaker 22 and stop the power supply.

As described above, when the disconnection detection device 1 of the present embodiment detects a disconnection, it repeatedly generates a forced ground fault at a timing different from that of other disconnection detection devices 1 in the system, and then the power supply is stopped. Until then, the forced ground fault condition was continued. As a result, the occurrence location of the disconnection accident can be specified on the distribution substation 2 side, and the power supply can be stopped to prevent a disaster such as an electric shock accident.

As described above, the disconnection detection device according to the present invention is useful as a device that detects a disconnection of a distribution line in a distribution system and notifies a substation.

1, 1a disconnection detection device, 2, distribution substation, 11, 11a disconnection detection unit, 12, 12a disconnection notification unit, 21 ground fault detection relay, 22 breaker, 23 transformer.

Claims

In the power distribution system,
A disconnection detector that detects disconnection of the distribution line that the ground fault detection relay in the substation does not detect;
When a disconnection is detected by the disconnection detection unit, a disconnection accident notification that causes the ground fault detection relay to recognize the occurrence of an accident by grounding a second distribution line different from the first distribution line in which the disconnection is detected And
A disconnection detecting device comprising:
2. The disconnection detection according to claim 1, wherein the disconnection accident notifying unit causes the second distribution line to be grounded when the state in which the disconnection detection unit detects the disconnection continues for a predetermined time. apparatus.
3. The disconnection detecting device according to claim 2, wherein the length of the predetermined time is different from a predetermined time used in another disconnection detecting device in the same distribution system.
In the operation of causing the second distribution line to ground, the disconnection accident notifying unit performs processing in which the first operation for grounding the second distribution line and the second operation for canceling the ground fault are performed as one cycle. The disconnection detecting device according to claim 1, wherein the disconnection detecting device is repeatedly executed.
At least one of the duration of the first operation, the length of the one cycle, and the number of repetitions of the processing is different from that used in other disconnection detection devices in the same distribution system. It is set as a value, The disconnection detection apparatus of Claim 4 characterized by the above-mentioned.
The disconnection detection device according to claim 4, wherein the disconnection accident notifying unit continues the state in which the second distribution line is grounded after repeating the process a predetermined number of times.
A determination device for determining a place where the disconnection detection device according to claim 3 is installed,
When a ground fault is detected when the location of the ground fault has not been completed, the power supply to the distribution system is temporarily stopped by controlling the circuit breaker installed on the distribution line in the distribution substation. After restarting the power supply, based on the elapsed time since restarting the power supply, the presence or absence of occurrence of a disconnection accident, and the disconnection detection device that detected the disconnection accident is determined.
A determination apparatus characterized by that.
A determination device for determining a place where the disconnection detection device according to claim 5 is installed,
When a periodic ground fault is detected, it is determined that a disconnection accident has occurred, and a disconnection accident is detected based on the duration of one ground fault, the frequency of occurrence of the ground fault, and the number of occurrences. Determine the disconnection detection device,
A determination apparatus characterized by that.
A disconnection detecting device according to claim 2;
When a ground fault is detected, the circuit breaker installed on the distribution line in the distribution substation is controlled to temporarily stop the power supply to the distribution system, then restart the power supply and detect the ground fault again. A determination device that determines whether or not a disconnection accident has occurred based on the elapsed time from restarting the power supply to detecting the ground fault again.
A disconnection detection system comprising:
A disconnection detecting device according to claim 4;
A determination device that determines that a disconnection accident has occurred when a state in which a periodic ground fault has occurred is detected;
A disconnection detection system comprising: