Vacuum valve abnormality determination device and vacuum valve abnormality determination method

Abstract

To provide an abnormality determination device of a vacuum valve, capable of correctly determining whether or not a partial discharge to be detected is due to an abnormality.SOLUTION: A vacuum valve abnormality determination device (1) comprises: a discharge detection part (20); a cutoff detection part (21); and a determination part (25). The discharge detection part detects a partial discharge in a container (51) into which a vacuum valve (52) of a vacuum breaker (5). The cutoff detection part detects a cutoff operation of a main circuit current by a vacuum cutoff device. The determination part determines the presence / absence of an abnormality of the vacuum valve on the basis of whether or not the cutoff operation is executed before the generation of the partial discharge.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to an apparatus for determining an abnormality of a vacuum valve used in a vacuum circuit breaker, and a method for determining an abnormality of the vacuum valve.

Background Art

[0002] As a current breaker in power receiving and distributing equipment using a large current such as a substation, a vacuum circuit breaker equipped with a vacuum valve may be used. In order to ensure the current interruption performance of the vacuum circuit breaker, it is necessary to detect an abnormality of the vacuum valve, such as a decrease in the degree of vacuum of the vacuum valve.

[0003] Since it is difficult to directly measure the degree of vacuum of the vacuum valve, for detecting an abnormality of the vacuum valve, for example, as described in Patent Document 1, a method of detecting discharge generated between internal electrodes of the vacuum valve by an antenna may be adopted. Patent Document 1 further discloses a technique of calculating a frequency from the detected current waveform of the discharge and determining whether or not the discharge is caused by an abnormality of the vacuum valve based on the frequency.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In recent years, in the specifications of vacuum valves, the frequency band of partial discharge signals generated due to abnormalities in vacuum valves, such as vacuum deterioration of vacuum valves, may include frequency components at almost the same level from the low-frequency range to around 200 MHz. In addition, when a vacuum circuit breaker using a vacuum valve performs a current interruption operation, non-sustained (rupture) discharges (NSDD: Non-Sustained Disruptive Discharges) may occur immediately afterwards regardless of abnormalities in the vacuum valve. In the method described in Patent Document 1, it is difficult to determine whether the detected discharge is caused by an abnormality in the vacuum valve or NSDD.

Means for Solving the Problems

[0006] A vacuum valve abnormality determination device according to an aspect of the present disclosure includes a discharge detection unit that detects partial discharge in a container in which a vacuum valve of a vacuum circuit breaker is stored, a cutoff detection unit that detects a cutoff operation of a main circuit current by the vacuum circuit breaker, and a determination unit that determines the presence or absence of an abnormality in the vacuum valve based on whether the cutoff operation is being executed before the occurrence of the partial discharge.

[0007] A vacuum valve abnormality determination method according to an aspect of the present disclosure includes detecting partial discharge in a container in which a vacuum valve of a vacuum circuit breaker is stored, detecting a cutoff operation of a main circuit current by the vacuum circuit breaker, and determining the presence or absence of an abnormality in the vacuum valve based on whether the cutoff operation is being executed before the occurrence of the partial discharge.

Effects of the Invention

[0008] According to an aspect of the present disclosure, it is possible to more accurately determine whether the detected partial discharge is due to an abnormality in the vacuum valve.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Mode for Carrying Out the Invention

[0010] 〔Embodiment 1〕 <Vacuum Circuit Breaker: Overview> The vacuum valve abnormality determination device according to the present embodiment is a device for determining an abnormality of a vacuum valve, such as deterioration of the degree of vacuum of the vacuum valve provided in a vacuum circuit breaker described later. In particular, the vacuum valve abnormality determination device according to the present embodiment detects partial discharge in the container in which the vacuum valve is stored. Further, the vacuum valve abnormality determination device determines whether the partial discharge is caused by an abnormality of the vacuum valve or is a non-sustained (destructive) discharge (hereinafter, NSDD: Non-Sustained Disruptive Discharges). Thereby, the vacuum valve abnormality determination device determines the presence or absence of an abnormality of the vacuum valve.

[0011] In the present disclosure, "abnormality of the vacuum valve" does not only refer to physical deterioration of the vacuum valve itself, but may also include deterioration of the performance of the vacuum valve that can cause a decrease in the interrupting ability of the main circuit current by the vacuum circuit breaker using the vacuum valve. For example, in the present disclosure, "abnormality of the vacuum valve" may include a decrease in the degree of vacuum of the vacuum valve, in other words, vacuum deterioration of the vacuum valve. Further, in the present disclosure, "abnormality of the vacuum valve" may include deterioration of the performance of the vacuum valve due to adhesion of foreign matter to at least one of the vacuum valve and the pressure vessel storing the vacuum valve, or due to an abnormality in a part inside the container in which the vacuum valve is stored.

[0012] Also, in the present disclosure, "partial discharge in the container" refers to the entirety of partial discharges occurring inside the container of the vacuum circuit breaker described later. In particular, "partial discharge in the container" includes partial discharges occurring inside the vacuum valve stored inside the container.

[0013] FIG. 1 is a schematic diagram of the vacuum valve abnormality determination device and the vacuum circuit breaker. Note that a part of the vacuum circuit breaker 5 described later shown in FIG. 1 is shown with its interior transparent for simplicity of illustration.

[0014] First, the vacuum circuit breaker 5 in which the presence or absence of an abnormality of the vacuum valve 52 described later is determined by the vacuum valve abnormality determination device 1 shown in FIG. 1 will be described. The vacuum circuit breaker 5 has a function of preventing at least a part of the main circuit current from being energized at a specific position in a power distribution facility where a main circuit current having a relatively large voltage value or current value, such as a substation, flows. For example, the vacuum circuit breaker 5 interrupts at least a part of the main circuit current by an operation such as moving a movable electrode (not shown). In the present disclosure, it is assumed that the main circuit current is an alternating current having a predetermined frequency.

[0015] The vacuum circuit breaker 5 includes a container 51 and a vacuum valve 52 inside the container 51. The inside of the vacuum valve 52 is maintained at a substantially vacuum level where, for example, no arc occurs between internal electrodes (not shown). In order to improve the performance of interrupting the main circuit current by the vacuum circuit breaker 5, the arc extinction performance of the arc from the movable electrode, etc., it is necessary to maintain the degree of vacuum of the vacuum valve 52. Along with this, it is also necessary to monitor the abnormality of the vacuum valve 52 including a decrease in the degree of vacuum of the vacuum valve 52 and to determine the presence or absence of an abnormality in the vacuum valve 52.

[0016] <Vacuum circuit breaker: Auxiliary contact: Configuration> The vacuum circuit breaker 5 may include an auxiliary contact 4. FIG. 2 is an equivalent circuit diagram of the auxiliary contact 4. As shown in FIG. 2, the auxiliary contact 4 includes, for example, a first circuit 6 and a second circuit 7. The first circuit 6 includes a pair of detection electrodes 61, a pair of switch electrodes 62, and a movable conductive part 63. Further, the second circuit 7 includes a pair of detection electrodes 71, a pair of switch electrodes 72, and a movable conductive part 73.

[0017] A signal having a predetermined potential may be applied between the pair of detection electrodes 61 and between the pair of detection electrodes 71.

[0018] The movable conductive part 63 can move between a position in contact with both of the pair of switch electrodes 62 and a position away from both of the pair of switch electrodes 62. Thereby, the movable conductive part 63 switches between a state of electrically short - circuiting between the switch electrodes 62 and a state of electrically insulating between the switch electrodes 62. When the switch electrodes 62 are electrically short - circuited, a signal of a predetermined potential or more is detected from the detection electrodes 61, and when the switch electrodes 62 are not electrically short - circuited, a signal of a predetermined potential or more is not detected from the detection electrodes 61.

[0019] With the same configuration as described above, the movable conductive part 73 switches between a state of electrically short - circuiting between the switch electrodes 72 and a state of electrically insulating between the switch electrodes 72. When the switch electrodes 72 are electrically short - circuited, a signal of a predetermined potential or more is detected from the detection electrode 71, and when the switch electrodes 72 are electrically short - circuited, a signal of a predetermined potential or more is not detected from the detection electrode 71.

[0020] <Vacuum circuit breaker: Auxiliary contact: Operation> FIG. 3 is an equivalent circuit diagram showing examples of the operation of the auxiliary contact 4 before and after the execution of the interruption operation of the main circuit current by the vacuum circuit breaker 5.

[0021] For example, before the interruption operation of the main circuit current by the vacuum circuit breaker 5, during normal operation, the auxiliary contact 4 is configured as shown by the auxiliary contact 41 in FIG. 3. Specifically, in the auxiliary contact 41, the switch electrode 62 and the movable conductive part 63 of the first circuit 6 are separated and electrically insulated. For this reason, a signal of a predetermined potential or more is not detected from the detection electrode 61 of the auxiliary contact 41. On the other hand, during the above - mentioned normal operation, the switch electrode 72 and the movable conductive part 73 of the second circuit 7 are in contact and electrically short - circuited. For this reason, a signal of a predetermined potential or more is detected from the detection electrode 71 of the auxiliary contact 41.

[0022] Next, for example, when the interruption operation of the main circuit current by the vacuum circuit breaker 5 is executed, the auxiliary contact 4 is configured as shown by the auxiliary contact 42 in FIG. 3. Specifically, in the auxiliary contact 42, the switch electrode 62 and the movable conductive part 63 of the first circuit 6 are in contact and electrically short - circuited. For this reason, a signal of a predetermined potential or more is detected from the detection electrode 61 of the auxiliary contact 42. On the other hand, during the above - mentioned interruption operation, the switch electrode 72 and the movable conductive part 73 of the second circuit 7 are separated and electrically insulated. For this reason, a signal of a predetermined potential or more is not detected from the detection electrode 71 of the auxiliary contact 42. Therefore, the insulation and short - circuit of the switch electrodes 62 and 72 of the auxiliary contact 4 are switched in conjunction with the execution of the interruption operation of the vacuum circuit breaker 5.

[0023] FIG. 4 is a graph showing the change over time in the voltage value of the main circuit current 53 to be interrupted by the vacuum circuit breaker 5 and the potential of the signal flowing through the auxiliary contact 4. In particular, FIG. 4 shows the potentials of the signal 64 from the detection electrode 61 of the auxiliary contact 4 and the signal 74 from the detection electrode 71.

[0024] In the graph of FIG. 4, the time t1 is the time when the signal of the interruption command for the main circuit current 53 by the vacuum circuit breaker 5 is transmitted, and the time t2 is the time when the actual interruption operation of the main circuit current 53 is executed due to the movement of the movable electrode of the vacuum circuit breaker 5 or the like. Since a predetermined time is required from the transmission of the interruption command signal until the actual interruption operation by the vacuum circuit breaker 5 is executed, there is a predetermined period between the time t1 and the time t2.

[0025] Therefore, from after the time t1 until the time t2, the voltage value of the main circuit current 53 maintains the normal voltage 54. On the other hand, after the time t2, since the actual interruption operation of the main circuit current 53 by the vacuum circuit breaker 5 is executed, the voltage value of the main circuit current 53 changes to a recovery voltage 55 whose absolute value is lower than the absolute value of the voltage value of the normal voltage 54.

[0026] Before the main circuit current 53 is interrupted by the vacuum circuit breaker 5, the switch electrodes 62 of the auxiliary contact 4 are insulated, and the switch electrodes 72 are short-circuited. Therefore, the potential of the signal 64 is low, while the potential of the signal 74 is high. Also, the auxiliary contact 4 moves the movable conductive part 63 and the movable conductive part 73 in response to the transmission of the signal of the interruption command for the main circuit current 53 by the vacuum circuit breaker 5, short-circuits the switch electrodes 62, and insulates the switch electrodes 72. For this reason, at least after the time t2, the potential of the signal 64 is high, while the potential of the signal 74 is low.

[0027] Therefore, detecting the change in the potential of the signals from each of the detection electrodes 61 and 71 of the auxiliary contact 4 corresponds to detecting the interruption operation of the main circuit current 53 by the vacuum circuit breaker 5. Note that, since it takes time for the movable conductive parts 63 and 73 in the auxiliary contact 4 to move, there may be a slight difference in the times of the change in the potential between the signal 64 and the signal 74. In this case, in the present embodiment, the time t2 when the change in the potential of both the signal 64 and the signal 74 is completed may be regarded as the time when the interruption operation of the main circuit current 53 by the vacuum circuit breaker 5 is executed.

[0028] <Vacuum valve abnormality determination device: Overview> Referring to FIG. 1 again, the vacuum valve abnormality determination device 1 according to the present embodiment will be described. The vacuum valve abnormality determination device 1 shown in FIG. 1 includes a main body unit 2 and an antenna sensor 3.

[0029] The main body unit 2 is located, for example, outside the vacuum circuit breaker 5. The main body unit 2 includes a discharge detection unit 20, a cutoff detection unit 21, a timing unit 22, a discharge time specifying unit 23, a cutoff time specifying unit 24, a determination unit 25, a control unit 26, a memory 27, a display unit 28, and an operation unit 29. The main body unit 2 may include a power supply unit 2P that supplies power to each unit included in the main body unit 2.

[0030] <Vacuum valve abnormality determination device: Antenna sensor and discharge detection unit> The antenna sensor 3 is located, for example, inside the container 51 together with the vacuum valve 52 of the vacuum circuit breaker 5. Generally, when partial discharge occurs between the internal electrodes of the vacuum valve 52 or between the internal electrode and the shield of the vacuum valve 52, an electromagnetic wave is generated by the partial discharge. The antenna sensor 3 detects the electromagnetic wave and transmits a signal corresponding to the detected electromagnetic wave, for example, a signal having an intensity corresponding to the intensity of the detected electromagnetic wave, to the discharge detection unit 20.

[0031] The discharge detection unit 20 detects partial discharge in the container 51 in which the vacuum valve 52 of the vacuum circuit breaker 5 is stored by receiving a signal from the antenna sensor 3. The discharge detection unit 20 may specify the intensity of the partial discharge from the intensity of the signal received from the antenna sensor 3. When the discharge detection unit 20 detects the partial discharge, it may transmit a signal indicating that the partial discharge has been detected to a discharge time specifying unit 23 described later.

[0032] <Vacuum valve abnormality determination device: Interruption detection unit> The interruption detection unit 21 detects that the interruption operation of the main circuit current by the vacuum circuit breaker 5 has been executed. In the present embodiment, the interruption detection unit 21 may detect the interruption operation of the main circuit current by the vacuum circuit breaker 5 from the change in the potential of the signals 64 and 74 transmitted from the auxiliary contact 4 described above. When the interruption detection unit 21 detects the interruption operation, it may transmit a signal indicating that the interruption operation has been detected to an interruption time specifying unit 24 described later.

[0033] <Vacuum valve abnormality determination device: Timing unit> The timing unit 22 sequentially specifies the current time. The timing unit 22 may sequentially specify, for example, the local time at the location where the vacuum valve abnormality determination device 1 is installed as the current time. In this case, the timing unit 22 may include a conventionally known clock such as a radio clock. Alternatively, the timing unit 22 may sequentially specify the current time by sequentially measuring the elapsed time based on a certain time. For example, the timing unit 22 may sequentially measure the elapsed time based on the time at the time of power-on of the vacuum valve abnormality determination device 1, the time of power-on of the interruption detection unit 21, or the time separately set by the user of the vacuum valve abnormality determination device 1.

[0034] Note that the timing unit 22 is not limited to a configuration that sequentially specifies the time. For example, the timing unit 22 may sequentially specify the time between the occurrence of the partial discharge detected by the discharge detection unit 20 and the execution of the interruption operation detected by the interruption detection unit 21 as the first time. Also, when the discharge detection unit 20 detects partial discharge a plurality of times within a predetermined period, the timing unit 22 may sequentially specify the time between the plurality of partial discharges detected by the discharge detection unit 20 as the second time.

[0035] <Vacuum valve abnormality determination device: Discharge time specifying unit and interruption time specifying unit> The discharge time specifying unit 23 specifies the time when partial discharge occurs in the container 51 in which the vacuum valve 52 is stored. In particular, the discharge time specifying unit 23 specifies the time when the partial discharge occurs based on the detection of the partial discharge by the discharge detection unit 20. The discharge time specifying unit 23 may specify the time when the partial discharge occurs, for example, based on the current time specified by the timekeeping unit 22 at the time when a signal indicating the occurrence of the partial discharge transmitted from the discharge detection unit 20 is received. Alternatively, the discharge time specifying unit 23 may specify, for example, the time before a predetermined time from the time when the signal is received, taking into account the time difference from the actual occurrence of the partial discharge to the reception of the signal, as the discharge time.

[0036] The interruption time specifying unit 24 specifies the time when the interruption operation of the main circuit current by the vacuum circuit breaker 5 is executed. In particular, the interruption time specifying unit 24 specifies the time when the interruption operation is executed based on the detection of the interruption operation by the interruption detection unit 21. The interruption time specifying unit 24 may specify the time when the interruption operation is executed, for example, based on the current time specified by the timekeeping unit 22 at the time when a signal indicating the execution of the interruption operation transmitted from the interruption detection unit 21 is received. Alternatively, the interruption time specifying unit 24 may specify, for example, the time before a predetermined time from the time when the signal is received, taking into account the time difference from the actual execution of the interruption operation to the reception of the signal, as the interruption time. In particular, since time is required for the movement of the movable electrode and the like in the interruption operation, the interruption time specifying unit 24 can specify a more accurate interruption time by specifying the interruption time taking into account the above-described time difference.

[0037] When the discharge time specifying unit 23 receives a signal from the discharge detection unit 20, or when the interruption time specifying unit 24 receives a signal from the interruption detection unit 21, the discharge time specifying unit 23 or the interruption time specifying unit 24 may appropriately refer to the current time specified by the timekeeping unit 22. Alternatively, the timekeeping unit 22 may sequentially transmit a signal having information on the specified current time to the discharge time specifying unit 23 or the interruption time specifying unit 24.

[0038] Note that the discharge time specifying unit 23 may specify the discharge time of the partial discharge each time the discharge detection unit 20 detects a partial discharge. Therefore, when the discharge detection unit 20 detects a plurality of partial discharges within a predetermined period, the discharge time specifying unit 23 may specify the discharge time corresponding to each of the plurality of partial discharges. Further, in this case, the discharge time specifying unit 23 may specify the number of times the discharge time has been specified within a predetermined period, thereby specifying the number of partial discharges generated within the predetermined period.

[0039] <Vacuum valve abnormality determination device: determination unit> The determination unit 25 determines the presence or absence of an abnormality in the vacuum valve 52 based on whether or not a shut-off operation is being executed before the occurrence of a partial discharge. For example, the determination unit 25 determines the presence or absence of an abnormality in the vacuum valve 52 based on whether or not the shut-off time specified by the shut-off time specifying unit 24 is before the discharge time specified by the discharge time specifying unit 23.

[0040] Note that, although details will be described later, the determination unit 25 may determine whether or not there is continuity in the partial discharges based on the period from the occurrence of one partial discharge to the occurrence of another. Further, the determination unit 25 may count the number of partial discharges generated within a predetermined period. Furthermore, the determination unit 25 may determine whether or not the interval between the occurrences of the generated partial discharges is synchronized with the frequency of the main circuit current to be interrupted by the vacuum circuit breaker 5 based on the interval between the generated partial discharges and the frequency of the main circuit current.

[0041] <Vacuum valve abnormality determination device: supplement> The control unit 26 includes a processor such as a CPU for controlling the operations of each part of the main body unit 2. The control unit 26 may control the operations of each part of the main body unit 2 according to, for example, a preset algorithm. Further, a signal having predetermined information from each part of the main body unit 2 may be transmitted to the control unit 26.

[0042] For example, the control unit 26 may determine the control content of the discharge time specifying unit 23, the cutoff time specifying unit 24, and the determination unit 25 based on the information included in the signals transmitted from the discharge time specifying unit 23, the cutoff time specifying unit 24, and the determination unit 25. Further, the control unit 26 may transmit a signal having the information on the control content to the discharge time specifying unit 23, the cutoff time specifying unit 24, and the determination unit 25 to control the discharge time specifying unit 23, the cutoff time specifying unit 24, and the determination unit 25. For example, the discharge detection unit 20, the cutoff detection unit 21, and the timing unit 22 may operate according to a predetermined algorithm without receiving a direct control command from the control unit 26, but on the other hand, they may be controlled by the control unit 26.

[0043] The memory 27 records at least temporarily, for example, the information included in the signal transmitted to the control unit 26 based on the signal from the control unit 26. The information recorded in the memory 27 may be appropriately read out by the control unit 26, for example. For example, the control content of each part of the main body unit 2 by the control unit 26 may be recorded in the memory 27 in advance. Note that the recording of information in the memory 27 or the reading of information from the memory 27 may be directly performed by each part of the main body unit 2 without passing through the control unit 26.

[0044] The display unit 28 may display, for example, the information required by the user of the vacuum valve abnormality determination device 1, such as the operation status of the vacuum valve abnormality determination device 1, based on the signal from the control unit 26. The display unit 28 may display at least a part of the information including the signal transmitted from the control unit 26 or the information recorded in the memory 27, for example.

[0045] The operation unit 29 may include buttons or the like that can be operated by the user of the vacuum valve abnormality determination device 1, and may transmit a signal indicating that a specific operation has been performed to the control unit 26. The control unit 26 may determine the control content of each part of the main body unit 2 according to the signal from the operation unit 29.

[0046] The main body 2 may also include a communication unit (not shown) that includes various means including conventionally known means such as wired or wireless means. For example, based on a signal from the control unit 26, the communication unit may transmit information included in signals transmitted from each part of the main body 2 or information recorded in the memory 27 to a device outside the main body 2. Alternatively, the communication unit may receive a signal transmitted from outside the main body 2, and may transmit the received signal to each part of the main body 2 including the control unit 26 or the memory 27.

[0047] <Vacuum valve abnormality determination method: Detection of partial discharge and interruption operation> A vacuum valve abnormality determination method using the vacuum valve abnormality determination device 1 will be described with reference to FIG. 5. FIG. 5 is a flowchart of the vacuum valve abnormality determination method by the vacuum valve abnormality determination device 1 according to the present embodiment.

[0048] During the execution of the vacuum valve abnormality determination method using the vacuum valve abnormality determination device 1, the timing unit 22 may sequentially specify the current time. Each part of the vacuum valve abnormality determination device 1 may use the current time specified by the timing unit 22 at the time when each operation described later occurs as the time when the operation occurred. In other words, in the vacuum valve abnormality determination method, the timing unit 22 may sequentially specify the current time. Alternatively, in the vacuum valve abnormality determination method, the timing unit 22 may sequentially specify at least one of the first time and the second time described above.

[0049] In the vacuum valve abnormality determination method, first, the determination unit 25 determines whether or not partial discharge in the container 51 has been detected (step S1). In particular, in step S1, the determination unit 25 may determine whether or not partial discharge in the container 51 in which the vacuum valve 52 of the vacuum circuit breaker 5 is stored has been detected by the discharge detection unit 20.

[0050] In step S1, when the determination unit 25 determines that partial discharge has not been detected, the vacuum valve abnormality determination device 1 continues to monitor the partial discharge in the container 51 by having the determination unit 25 determine the presence or absence of partial discharge detected by the discharge detection unit 20, etc. (step S2). After a predetermined period from step S2, the vacuum valve abnormality determination device 1 may execute step S1 again. Thereby, the vacuum valve abnormality determination device 1 may continuously monitor the occurrence of partial discharge until partial discharge is detected.

[0051] During the execution of steps S1 and S2, the discharge detection unit 20 continuously detects partial discharge in the container 51. Also, each time the discharge detection unit 20 detects partial discharge in the container 51, the discharge time specifying unit 23 may specify the time when the partial discharge was detected as the discharge time and record it in the memory 27 or the like. Therefore, when the discharge detection unit 20 detects a plurality of partial discharges, the discharge time specifying unit 23 may specify the discharge time for each partial discharge.

[0052] During the execution of steps S1 and S2, the interruption detection unit 21 continuously detects the interruption operation of the main circuit current by the vacuum circuit breaker 5. Also, each time the interruption detection unit 21 detects the interruption operation of the main circuit current by the vacuum circuit breaker 5, the interruption time specifying unit 24 may specify the time when the interruption operation was detected as the interruption time and record it in the memory 27 or the like.

[0053] <Vacuum Valve Abnormality Determination Method: Comparison between Discharge Time and Interruption Time> Suppose that in step S1, the determination unit 25 determines that partial discharge has been detected by specifying that the discharge detection unit 20 is receiving a signal from the antenna sensor 3, etc. In this case, the determination unit 25 determines whether or not the detection of partial discharge is immediately after the interruption of the main circuit current by the vacuum circuit breaker 5 (step S3).

[0054] For example, in step S3, the determination unit 25 determines whether or not the above-described interruption time is recorded in the memory 27. Thereby, the determination unit 25 determines whether or not the interruption time is before the discharge time. In other words, the determination unit 25 determines whether or not the interruption operation has been executed before the occurrence of the partial discharge.

[0055] If it is determined that the interruption time is recorded before the discharge time, the determination unit 25 may determine that the interruption time is before the discharge time. In this case, the determination unit 25 may further compare the interruption time with the discharge time which is the occurrence time of the identified partial discharge, and determine whether or not the discharge time is within a certain period from the interruption time. In other words, the determination unit 25 may determine whether or not the time between the occurrence of the partial discharge and the execution of the interruption operation is within a predetermined period.

[0056] Also, when the discharge time specifying unit 23 has already specified a plurality of discharge times in step S1, in step S3, the determination unit 25 may determine, for example, whether or not the first discharge time among the plurality of specified discharge times is within the first period from the interruption time. In other words, when the partial discharge has been detected a plurality of times by the discharge detection unit 20, the determination unit 25 may determine whether or not the occurrence of the first partial discharge among the detected partial discharges is within the first period from the execution of the interruption operation.

[0057] The first period is a predetermined period from the time t2 when the interruption operation of the main circuit current by the vacuum circuit breaker 5 is executed, as shown as the first period P1 in FIG. 4 for example. Specifically, the first period P1 may be 1 second or less.

[0058] NSDDs that occur regardless of the abnormality of the vacuum valve 52 have been found to tend to occur immediately after the interruption operation of the main circuit current by the vacuum circuit breaker 5. Therefore, when the interruption operation by the vacuum circuit breaker 5 has been executed before the time when partial discharge occurs, the probability that the above partial discharge is NSDD is high. Thus, by determining whether or not the interruption operation has been executed before the occurrence of the partial discharge, the determination unit 25 can determine whether or not the partial discharge detected by the discharge detection unit 20 is NSDD. In particular, the determination unit 25 can more efficiently determine whether or not the partial discharge detected by the discharge detection unit 20 is NSDD by determining whether or not the discharge time is within the first period from the interruption time. Note that the determination unit 25 may make the above determination based on whether or not the first time, which is the time from the execution of the interruption operation to the occurrence of the first partial discharge specified by the timekeeping unit 22, is longer than the first period.

[0059] <Method for determining abnormality of vacuum valve: Determination of presence or absence of continuity of partial discharge> Suppose that in step S3, the determination unit 25 determines that the occurrence of the partial discharge is immediately after the interruption of the main circuit current by the vacuum circuit breaker 5, in other words, the interruption time is before the discharge time. In this case, the determination unit 25 then determines whether or not there is continuity in the detection of the partial discharge (step S4).

[0060] In step S4, the determination unit 25 determines, for example, whether there are multiple partial discharges detected by the discharge detection unit 20 or multiple times of partial discharge specified by the discharge time specifying unit 23, and determines whether multiple partial discharges have occurred. When the determination unit 25 determines that multiple partial discharges have occurred, then the determination unit 25 determines whether a partial discharge has occurred beyond a second period, which is a predetermined period from the time when one of the multiple partial discharges occurred, for example, the time when the partial discharge first detected after executing step S1 occurred. The second period is a period longer than the first period, for example, and may specifically be 1 second or more. Note that the determination unit 25 may make the above determination based on whether a second time, which is the time from the occurrence of the first partial discharge to the occurrence of the last partial discharge specified by the timing unit 22, is longer than the second period. In other words, the determination unit 25 determines whether, among multiple partial discharges, one of the partial discharges has occurred beyond the second period from the occurrence of another partial discharge.

[0061] Partial discharges caused by an abnormality of the vacuum valve 52 occur regardless of whether or not the main circuit current is interrupted by the vacuum circuit breaker 5. For this reason, even if the detected partial discharge occurred immediately after the main circuit current was interrupted by the vacuum circuit breaker 5, the partial discharge may be a partial discharge caused by an abnormality of the vacuum valve 52. However, it has been found that NSDD rarely occurs continuously for a predetermined period or more after the first occurrence. For this reason, by setting the second period so as to include a period during which NSDD does not occur and causing the determination unit 25 to determine whether partial discharges have occurred continuously beyond the second period, the determination unit 25 can determine whether the detected partial discharge is NSDD.

[0062] <Vacuum Valve Abnormality Determination Method: Determination of NSDD> Suppose that in step S4, the determination unit 25 determines that multiple partial discharges have not occurred, or determines that there is no continuity among multiple partial discharges. In other words, suppose that the determination unit 25 determines that the discharge time of one of the multiple partial discharges is not recorded beyond the second period from the other discharge time. In this case, the determination unit 25 determines that the detected partial discharge is NSDD (step S5).

[0063] In this case, since it is considered that the detected partial discharge is not associated with the abnormality of the vacuum valve 52, the user of the vacuum valve abnormality determination device 1 does not need to perform operations such as inspection of the vacuum valve 52. Further, after step S5, the vacuum valve abnormality determination device 1 may execute step S1 again.

[0064] After the execution of step S5, the vacuum valve abnormality determination device 1 may once erase the record of the cutoff time from the memory 27 or the like. Thereby, when step S3 is executed again, it is possible to more accurately determine whether the partial discharge is NSDD or is associated with the abnormality of the vacuum valve 52.

[0065] <Vacuum valve abnormality determination method: Recording and determination of the number of partial discharges> Suppose that in step S4, the determination unit 25 determines that there is continuity among a plurality of partial discharges, in other words, one discharge time among the plurality of partial discharges is recorded beyond the second period from another discharge time. In this case, for example, the determination unit 25 records the number of occurrences of partial discharges in a predetermined period (step S6).

[0066] In step S6, the determination unit 25 records the number of partial discharges that occurred during the second period from the occurrence of one of the plurality of generated partial discharges, for example, the first partial discharge. The recording of the number by the determination unit 25 in step S6 may be executed by referring to the plurality of discharge times recorded in the memory 27 and counting the number of discharge times recorded from the first discharge time of the plurality of discharge times to the second period.

[0067] Next, in step S6, the determination unit 25 determines whether or not the number of occurrences of partial discharges in a predetermined period exceeds a predetermined value (step S7). In step S7, the determination unit 25 may compare the number recorded in step S6 with a preset predetermined value to determine whether or not the number exceeds the predetermined value.

[0068] In other words, for example, when the discharge detection unit 20 detects a plurality of partial discharges during the second period after detecting the first partial discharge, the discharge time specifying unit 23 counts the number of discharge times specified during the second period in addition to specifying the discharge time of each partial discharge. Thereby, the determination unit 25 specifies the number of partial discharges generated during the second period, and determines whether or not the number exceeds a predetermined value.

[0069] Generally, regardless of the type of abnormality of the vacuum valve 52, when any abnormality occurs in the vacuum valve 52, the frequency of occurrence of partial discharges increases. For this reason, when the number of partial discharges occurring in a predetermined period exceeds a predetermined value, the type of abnormality that has occurred in the vacuum valve 52 can be determined by specifying the cause of the partial discharges occurring during that period. The above-mentioned predetermined value may be, for example, two or more times.

[0070] Suppose that in step S7, the determination unit 25 determines that the number of partial discharges occurring in the predetermined period does not exceed the predetermined value. In other words, suppose that the determination unit 25 determines that the number of discharge times recorded from the first discharge time of the plurality of discharge times to the end of the second period is less than or equal to the predetermined value. In this case, since the type of abnormality of the vacuum valve 52 cannot be specified, the vacuum valve abnormality determination device 1 executes step S1 again.

[0071] <Vacuum Valve Abnormality Determination Method: Determination of Vacuum Valve Abnormality> On the other hand, suppose that in step S7, the determination unit 25 determines that the number of partial discharges occurring in the predetermined period exceeds the predetermined value. In other words, suppose that the determination unit 25 determines that the number of discharge times recorded from the first discharge time of the plurality of discharge times to the end of the second period exceeds the predetermined value. In this case, the determination unit 25 determines that the detected partial discharge is due to an abnormality of the vacuum valve 52 (step S8).

[0072] In this case, the user of the vacuum valve abnormality determination device 1 may inspect the vacuum valve 52 or the like. Further, the vacuum valve abnormality determination device 1 may notify the user to inspect the vacuum valve 52 by means of display on the display unit 28 or lighting of a lamp by opening of an abnormality contact (not shown). After the user of the vacuum valve abnormality determination device 1 performs operations such as inspection or replacement of the vacuum valve 52, the user may operate the vacuum valve abnormality determination device 1 again by operating the operation unit 29 or the like. Subsequently, the vacuum valve abnormality determination device 1 may execute step S1 again.

[0073] In particular, in the above case, it has been found that there is continuity in a plurality of identified partial discharges. Therefore, in the above case, it is conceivable that an abnormality of the vacuum valve 52 or the container 51 occurs constantly, such as a decrease in the degree of vacuum of the vacuum valve 52 or adhesion of foreign matter to at least one of the vacuum valve 52 and the container 51 in which the vacuum valve 52 is stored. Thus, the determination unit 25 can determine the cause of the partial discharge, in other words, the type of abnormality of the vacuum valve 52, by specifying the characteristics of the partial discharge during the period in which the partial discharge occurs a predetermined number of times or more within a predetermined period.

[0074] <Vacuum valve abnormality determination method: Determination of presence or absence of synchronization between partial discharge and main circuit current> Describing with reference to step S3 described above. Assume that in step S3, the determination unit 25 determines that the detection of the partial discharge is not immediately after the interruption of the main circuit current by the vacuum circuit breaker 5, in other words, the interruption time is not before the discharge time. In this case, the determination unit 25 determines whether the interval between the occurrences of the partial discharges is synchronized with the frequency of the main circuit current (step S9).

[0075] In step S9, for example, the determination unit 25 determines whether there are multiple partial discharges detected by the discharge detection unit 20 or multiple times of partial discharges specified by the discharge time specifying unit 23, and determines whether multiple partial discharges have occurred. When the determination unit 25 determines that multiple partial discharges have occurred, then the determination unit 25 determines whether there is a correlation between the time intervals of each of the multiple partial discharges that have occurred and the frequency of the main circuit current to be interrupted by the vacuum circuit breaker 5. In other words, the determination unit 25 determines whether the interval is synchronized with the period of the main circuit current based on the intervals between the occurrences of the multiple partial discharges. When there is a correlation between the intervals between the occurrences of the multiple partial discharges and the frequency of the main circuit current, the determination unit 25 determines that the detection of the partial discharges is synchronized with the frequency of the main circuit current.

[0076] <Vacuum valve abnormality determination method: Relationship between detected signal and voltage value of main circuit current> Regarding the specific method of step S9, it will be described with reference to FIG. 6. FIG. 6 is a graph showing the change over time of the voltage value of the main circuit current to be interrupted by the vacuum circuit breaker 5 and the intensity of the signal detected by the discharge detection unit 20. In the graph of FIG. 6, the horizontal axis represents time, and the vertical axis represents the voltage of the main circuit current or the intensity of the signal detected by the discharge detection unit 20. The graph G1 in FIG. 6 shows an example in the case where the generated partial discharge is NSDD, and the graph G2 in FIG. 6 shows an example in the case where the generated partial discharge is due to an abnormality of the vacuum valve 52.

[0077] In the graph G1 of FIG. 6, the change over time of the signal detected by the discharge detection unit 20, particularly the intensity of the signal 31 transmitted by the antenna sensor 3, is shown. Also, since the main circuit current is an alternating current, as shown in the graphs G1 and G2 of FIG. 6, the voltage of the main circuit current changes periodically over time according to a predetermined frequency.

[0078] However, the change over time of the intensity of signal 31 changes over time independently of the periodic change over time of the voltage of the main circuit current. This is because NSDD occurs at random times regardless of the voltage value of the main circuit current. Therefore, it can be seen that there is no correlation between the detection of signal 31 and the frequency of the main circuit current, and the detection of partial discharge is not synchronized with the frequency of the main circuit current.

[0079] Note that the correlation between the intensity of the signal detected by the discharge detection unit 20 and the frequency of the main circuit current may be determined from the difference in the number of peaks of the signal detected by the discharge detection unit 20 during each of the period when the voltage of the main circuit current is positive voltage application and the period when it is negative voltage application. In this case, when the difference is less than or equal to a predetermined value, it may be determined that there is no correlation between the intensity of the signal detected by the discharge detection unit 20 and the frequency of the main circuit current.

[0080] Alternatively, the correlation between the intensity of the signal detected by the discharge detection unit 20 and the frequency of the main circuit current may be determined by calculating a plurality of time intervals when the intensity of the signal detected by the discharge detection unit 20 exceeds a predetermined value. In this case, when the difference in the above intervals exceeds a predetermined value during a predetermined period, it may be determined that there is no correlation between the intensity of the signal detected by the discharge detection unit 20 and the frequency of the main circuit current.

[0081] On the other hand, the graph G2 in FIG. 6 shows the change over time of the intensity of the signal detected by the discharge detection unit 20, particularly the signal 32 transmitted by the antenna sensor 3. As shown in the graph G2 of FIG. 6, the change over time of the intensity of signal 32 changes periodically roughly along with the periodic change over time of the voltage of the main circuit current. This is because the probability of partial discharge occurring due to the abnormality of the vacuum valve 52 changes according to the voltage value of the main circuit current. In particular, partial discharge due to the abnormality of the vacuum valve 52 tends to occur more easily as the potential difference between the interruption electrodes of the vacuum circuit breaker 5 increases. Therefore, it can be seen that there is a correlation between the detection of signal 32 and the frequency of the main circuit current, and the detection of partial discharge is synchronized with the frequency of the main circuit current.

[0082] <Vacuum valve abnormality determination method: Further improvement of determination accuracy> Referring to FIG. 5 again, assume that in step S9, the determination unit 25 determines that the interval of occurrence of partial discharge is not synchronized with the frequency of the main circuit current. In this case, the vacuum valve abnormality determination device 1 executes steps S6 and S7 described above, and thereafter executes the same processing as each of the steps described above.

[0083] For example, assume that the abnormality of the vacuum valve 52 is not a physical abnormality of the vacuum valve 52 itself such as vacuum deterioration of the vacuum valve 52. In particular, for example, assume that the abnormality of the vacuum valve 52 is a deterioration in the performance of the vacuum valve 52 such as adhesion of foreign matter to at least one of the vacuum valve 52 and the container 51 in which the vacuum valve 52 is stored or deterioration of the container 51. In this case, even if the partial discharge is associated with the abnormality of the vacuum valve 52, the detection of the partial discharge may not be synchronized with the frequency of the main circuit current. Therefore, even when it is determined in step S9 that the interval of occurrence of partial discharge is not synchronized with the frequency of the main circuit current, by executing steps S6 and S7, the accuracy of determining the cause of the partial discharge is improved.

[0084] Assume that in step S9, the determination unit 25 determines that the interval of occurrence of partial discharge is synchronized with the frequency of the main circuit current. In this case, the determination unit 25 determines whether there is continuity in the occurrence of partial discharge by, for example, the same method as step S4 described above (step S10).

[0085] Even when the partial discharge is a deterioration in the performance of the vacuum valve 52 described above, occasionally the occurrence of the partial discharge may be synchronized with the time corresponding to the frequency of the main circuit current. In this case, the determination unit 25 may determine that the detection of the partial discharge is synchronized with the frequency of the main circuit current. Therefore, even when it is determined in step S9 that the occurrence of partial discharge is synchronized with the frequency of the main circuit current, by executing step S10, the accuracy of determining the cause of the partial discharge is improved.

[0086] When the determination unit 25 determines in step S10 that there is no continuity in the partial discharge, the vacuum valve abnormality determination device 1 executes steps S6 and S7 described above, and thereafter executes the same processing as each of the steps described above. When the determination unit 25 determines in step S10 that there is continuity in the partial discharge, the determination unit 25 determines that the detected partial discharge is due to an abnormality of the vacuum valve 52 (step S8).

[0087] When the occurrence of the partial discharge is synchronized with the frequency of the main circuit current and there is continuity in the occurrence of the partial discharge, it is highly probable that the abnormality of the vacuum valve 52 is a physical abnormality of the vacuum valve 52 such as a decrease in the vacuum degree of the vacuum valve 52. On the other hand, when the occurrence of the partial discharge is synchronized with the frequency of the main circuit current while there is no continuity in the occurrence of the partial discharge, the probability that the abnormality of the vacuum valve 52 is a physical abnormality of the vacuum valve 52 becomes low.

[0088] As described above, the vacuum valve abnormality determination device 1 continuously monitors the partial discharge in the container 51, and determines whether the partial discharge is NSDD or due to an abnormality of the vacuum valve 52 when the partial discharge occurs. Further, when the cause of the partial discharge is due to an abnormality of the vacuum valve 52, the determination unit 25 can determine the cause of the abnormality.

[0089] <Improvement in the determination accuracy of the vacuum valve abnormality> The vacuum valve abnormality determination device 1 according to the present embodiment detects a partial discharge in the container 51 in which the vacuum valve 52 of the vacuum circuit breaker 5 is stored. Further, the determination unit 25 determines the abnormality of the vacuum valve 52 based on whether the detected partial discharge occurred immediately after the interruption operation of the main circuit current by the vacuum circuit breaker 5.

[0090] Therefore, the vacuum valve abnormality determination device 1 can determine the abnormality of the vacuum valve 52 without specifying the frequency of the electromagnetic wave generated by the partial discharge that has occurred. In particular, the vacuum valve abnormality determination device 1 can more accurately determine whether the partial discharge that has occurred is NSDD that occurs immediately after the interruption operation of the main circuit current by the vacuum circuit breaker 5. Therefore, the vacuum valve abnormality determination device 1 can more accurately determine whether the detected partial discharge is due to an abnormality of the vacuum valve 52.

[0091] The determination unit 25 can also determine the abnormality of the vacuum valve 52 based on the continuity or number of partial discharges generated during the second period, or based on the presence or absence of synchronization between the partial discharges generated during the second period and the frequency of the main circuit current. Thereby, the vacuum valve abnormality determination device 1 can more accurately determine whether the detected partial discharge is due to an abnormality of the vacuum valve 52, or can determine the type of abnormality of the vacuum valve 52.

[0092] Note that the method for determining the presence or absence of an abnormality of the vacuum valve 52 by the determination unit 25 is not limited to the method shown in FIG. 5 as long as it includes at least the determination of the presence or absence of an abnormality of the vacuum valve 52 based on whether or not an interruption operation has been performed before the occurrence of partial discharge. For example, the determination unit 25 may determine the presence or absence of an abnormality of the vacuum valve 52 only based on whether or not an interruption operation has been performed before the occurrence of partial discharge. On the other hand, the determination unit 25 may determine the abnormality of the vacuum valve 52 based on at least one of the continuity of the partial discharges generated during the second period, the number of partial discharges, and the presence or absence of synchronization between the partial discharges generated during the second period and the frequency of the main circuit current. In other words, the determination unit 25 may omit the implementation of any of steps S4, 6, 7, 9, and 10 among the steps shown in FIG. 5.

[0093] For example, when the interruption operation has been performed before the occurrence of partial discharge, the determination unit 25 may determine that the probability that the partial discharge is NSDD is high. Further, when the interruption operation has not been performed before the occurrence of partial discharge, the determination unit 25 may determine that the probability that the partial discharge is a discharge associated with an abnormality of the vacuum valve 52 is high.

[0094] When there is no continuity in the occurrence of a plurality of partial discharges during the second period, the determination unit 25 may determine that the probability that the plurality of partial discharges are NSDD is high. Further, when there is continuity in the occurrence of a plurality of partial discharges during the second period, the determination unit 25 may determine that the probability that the plurality of partial discharges are discharges associated with an abnormality of the vacuum valve 52 is high.

[0095] The determination unit 25 may compare the probability that the partial discharge detected by the discharge detection unit 20 is NSDD, determined by the method described above, with the probability that the partial discharge is a discharge associated with an abnormality of the vacuum valve 52. In this case, the determination unit 25 may comprehensively refer to the probability that the partial discharge is NSDD and the probability that the partial discharge is a discharge associated with an abnormality of the vacuum valve 52, and determine whether the partial discharge is NSDD or a discharge associated with an abnormality of the vacuum valve 52.

[0096] The vacuum valve abnormality determination device 1 includes a timing unit 22, and the timing unit 22 identifies the time when the partial discharge occurred and the time when the interruption operation of the main circuit current by the vacuum circuit breaker 5 was executed. Alternatively, the vacuum valve abnormality determination device 1 identifies the time between the occurrence of the partial discharge and the execution of the interruption operation, or the interval between a plurality of partial discharges, by the first time or the second time identified by the timing unit 22. Thereby, the vacuum valve abnormality determination device 1 can more accurately identify the discharge time, the interruption time, the first time, or the second time, and can more accurately determine whether the detected partial discharge is due to an abnormality of the vacuum valve 52.

[0097] 〔Embodiment 2〕 <Overcurrent relay and trip coil> Other embodiments of the present disclosure will be described below. For convenience of explanation, members having the same functions as the members described in the above embodiment are denoted by the same reference numerals, and the description thereof will not be repeated.

[0098] FIG. 7 is a schematic diagram of the vacuum valve abnormality determination device 1 and the vacuum circuit breaker 8 according to the present embodiment. The vacuum valve abnormality determination device 1 according to the present embodiment has the same configuration as the vacuum valve abnormality determination device 1 according to the previous embodiment. The vacuum circuit breaker 8 according to the present embodiment is different in configuration only in that it includes an overcurrent relay 9 as compared with the vacuum circuit breaker 5 according to the previous embodiment and the auxiliary contact 4.

[0099] The overcurrent relay 9 is connected, for example, in a circuit through which the main circuit current flows, or between another device different from a device having a circuit through which the main circuit current flows, and monitors the current value of the main circuit current flowing through a predetermined section. When the overcurrent relay 9 detects an abnormality such as a state where the current value of the main circuit current exceeds a certain threshold value continues for a predetermined period or more, the overcurrent relay 9 causes the vacuum circuit breaker 8 to execute a breaking operation of the main circuit current. Thereby, the overcurrent relay 9 prevents, for example, an overload or a short circuit to a device in which the main circuit current is not supposed to flow.

[0100] For example, the overcurrent relay 9 includes a trip coil 91. Before the breaking operation of the main circuit current by the vacuum circuit breaker 8 is executed, no voltage is applied to the trip coil 91. When the overcurrent relay 9 detects the above-described abnormality, for example, it applies a voltage to the trip coil 91. Thereby, the overcurrent relay 9 excites the magnetic flux from the trip coil 91 and moves the movable electrode or the like of the vacuum circuit breaker 8 to cause the vacuum circuit breaker 8 to execute a breaking operation of the main circuit current. The breaking detection unit 21 of the vacuum valve abnormality determination device 1 according to the present embodiment is connected to the trip coil 91 and measures the voltage value applied to the trip coil 91.

[0101] <Modification Example of Detection of Breaking Operation> The method for determining the vacuum valve abnormality by the vacuum valve abnormality determination device 1 according to the present embodiment is the same as the method for determining the vacuum valve abnormality according to the previous embodiment except for the method for detecting the breaking operation of the main circuit current by the vacuum circuit breaker 8. The method for detecting the breaking operation of the main circuit current by the vacuum circuit breaker 8 according to the present embodiment will be described with reference to FIG. 8.

[0102] FIG. 8 is a graph showing the change over time in the position 56 of the movable electrode of the vacuum circuit breaker 8, the voltage value 57 of the current flowing through the trip coil 91, and the intensity of the signal 33 detected by the discharge detection unit 20. The position 56 of the movable electrode shown in FIG. 8 moves from a high value to a low value due to the interruption operation of the main circuit current by the vacuum circuit breaker 8. Further, the signal 33 shown in FIG. 8 extracts only the peaks from the signals detected by the discharge detection unit 20, in other words, the signals transmitted by the antenna sensor 3. In other words, the time of the peak of the signal 33 shown in FIG. 8 represents the time when partial discharge occurred.

[0103] In the present embodiment, when a signal for instructing interruption of the main circuit current by the vacuum circuit breaker 8 is transmitted, a voltage is applied to the trip coil 91, and thus the voltage value 57 increases as shown in FIG. 8. Next, the movable electrode of the vacuum circuit breaker 8 is moved by the magnetic flux excited from the trip coil 91, and the position 56 moves from a high value to a low value. As described above, at time t2 shown in FIG. 8, the interruption operation of the main circuit current by the vacuum circuit breaker 8 is executed.

[0104] In the present embodiment, after the completion of the interruption operation of the main circuit current by the vacuum circuit breaker 8, the overcurrent relay 9 stops applying voltage to the trip coil 91. Therefore, the interruption detection unit 21 detects the interruption operation of the main circuit current by the vacuum circuit breaker 8 by measuring the voltage value of the voltage applied to the trip coil 91.

[0105] In the example shown in FIG. 8, peaks of a plurality of signals 33 are confirmed after time t2. Therefore, in the example shown in FIG. 8, it is considered that a plurality of partial discharges have occurred in the container 51 after time t2.

[0106] Assume that these signals 33 occur immediately after time t2, for example, within the first period P1 described above from time t2. Further, assume that the peaks of these signals 33 have no correlation with the frequency of the main circuit current, and are not confirmed after confirming the peaks of the signal 33 shown in FIG. 8 and are determined to have no continuity. In this case, the determination unit 25 determines that the plurality of partial discharges confirmed in the example shown in FIG. 8 are NSDD.

[0107] The vacuum valve abnormality determination device 1 according to the present embodiment can more accurately determine whether the detected partial discharge is due to an abnormality of the vacuum valve 52 for the same reason as described in the previous embodiment. Further, the interruption detection unit 21 of the vacuum valve abnormality determination device 1 according to the present embodiment detects an interruption operation from the voltage applied to the trip coil 91 of the vacuum circuit breaker 8. For this reason, the interruption detection unit 21 can detect the interruption operation by the vacuum circuit breaker 8 using the trip coil 91 necessary for the interruption operation of the main circuit current by the vacuum circuit breaker 8. Therefore, the vacuum valve abnormality determination device 1 according to the present embodiment improves the detection accuracy of the interruption operation by the interruption detection unit 21 while simplifying the configuration of the interruption detection unit 21.

[0108] <Summary> The vacuum valve abnormality determination device according to Aspect 1 of the present disclosure includes a discharge detection unit that detects partial discharge in a container in which a vacuum valve of a vacuum circuit breaker is stored, an interruption detection unit that detects an interruption operation of a main circuit current by the vacuum circuit breaker, and a determination unit that determines whether there is an abnormality of the vacuum valve based on whether the interruption operation has been executed before the occurrence of the partial discharge.

[0109] In the vacuum valve abnormality determination device according to Aspect 2 of the present disclosure, in the above Aspect 1, when the determination unit determines that the interruption operation has been executed before the occurrence of the partial discharge, the determination unit determines the partial discharge as a non-sustained discharge, and when the determination unit determines that the interruption operation has not been executed before the occurrence of the partial discharge, the determination unit determines the partial discharge as a discharge associated with an abnormality of the vacuum valve.

[0110] In the vacuum valve abnormality determination device according to Aspect 3 of the present disclosure, in the above Aspect 1 or 2, when the determination unit determines that the interruption operation has been executed before the occurrence of the partial discharge and a plurality of the partial discharges occur during a predetermined period, the determination unit determines the presence or absence of continuity of the plurality of partial discharges based on the period from the occurrence of one of the plurality of partial discharges to the occurrence of another one of the plurality of partial discharges, and determines the presence or absence of an abnormality of the vacuum valve based on the presence or absence of the continuity.

[0111] In the vacuum valve abnormality determination device according to aspect 4 of the present disclosure, in the above aspect 3, when there is no continuity among the plurality of partial discharges, the determination unit determines the plurality of partial discharges as non-sustained discharges.

[0112] In the vacuum valve abnormality determination device according to aspect 5 of the present disclosure, in the above aspect 3, when it is determined that there is continuity among the plurality of partial discharges and it is determined that the number of the partial discharges generated during the predetermined period is equal to or more than a predetermined number, the determination unit determines the type of abnormality of the vacuum valve.

[0113] In the vacuum valve abnormality determination device according to aspect 6 of the present disclosure, in the above aspect 1 or 2, when the determination unit determines that the interruption operation has not been executed before the occurrence of the partial discharge and a plurality of the partial discharges occur during a predetermined period after the partial discharge occurs, the determination unit determines whether the interval is synchronized with the period of the main circuit current based on the intervals between the occurrences of the plurality of partial discharges.

[0114] In the vacuum valve abnormality determination device according to aspect 7 of the present disclosure, in the above aspect 6, when the determination unit determines that the interval is synchronized with the period of the main circuit current, the determination unit determines the presence or absence of continuity among the plurality of partial discharges based on the interval, and when it is determined that there is continuity among the plurality of partial discharges, the determination unit determines the types of the plurality of partial discharges.

[0115] In the vacuum valve abnormality determination device according to aspect 8 of the present disclosure, in the above aspect 7, when the determination unit determines that there is no continuity among the plurality of partial discharges and it is determined that the number of the partial discharges generated during the predetermined period is equal to or more than a predetermined number, the determination unit determines the types of the plurality of partial discharges.

[0116] The vacuum valve abnormality determination device according to aspect 9 of the present disclosure is, in the above aspect 6, when the determination unit determines that the plurality of intervals and the period of the main circuit current are not synchronized, and determines that the number of partial discharges generated during the predetermined period is equal to or greater than a predetermined number, the determination unit determines the types of the plurality of partial discharges.

[0117] The vacuum valve abnormality determination device according to aspect 10 of the present disclosure is, in any one of the above aspects 1 to 9, a discharge time specifying unit that specifies a discharge time at which the partial discharge has occurred based on the detection of the partial discharge by the discharge detection unit, and a cutoff time specifying unit that specifies a cutoff time at which the cutoff operation has occurred based on the detection of the cutoff operation by the cutoff detection unit. The determination unit determines the presence or absence of an abnormality in the vacuum valve based on whether the cutoff time is before the discharge time.

[0118] The vacuum valve abnormality determination device according to aspect 11 of the present disclosure is, in any one of the above aspects 1 to 10, the cutoff detection unit detects the cutoff operation based on the voltage value of the voltage applied to the trip coil of the vacuum circuit breaker.

[0119] The vacuum valve abnormality determination method according to aspect 12 of the present disclosure includes detection of partial discharge in a container in which a vacuum valve of a vacuum circuit breaker is stored, detection of a cutoff operation of a main circuit current by the vacuum circuit breaker, and determination of the presence or absence of an abnormality in the vacuum valve based on whether the cutoff operation is being executed before the occurrence of the partial discharge.

[0120] The present disclosure is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present disclosure.

Description of Reference Numerals

[0121] 1 Vacuum valve abnormality determination device 5 Vacuum circuit breaker 20 Discharge detection unit 21 Cutoff detection unit 22 Timing unit 23 Discharge time specifying unit 24 Interruption time specifying unit 25 Determination unit 51 Container 52 Vacuum valve 91 Trip coil

Claims

1. A discharge detection unit that detects partial discharge in a container in which a vacuum valve of a vacuum circuit breaker is stored; A breaking detection unit that detects a breaking operation of the main circuit current by the vacuum circuit breaker; A determination unit that determines the presence or absence of an abnormality of the vacuum valve based on whether or not the breaking operation is being executed before the occurrence of the partial discharge. A vacuum valve abnormality determination device comprising the same.

2. When the determination unit determines that the breaking operation is being executed before the occurrence of the partial discharge, the determination unit determines the partial discharge as a non-sustained discharge, and before the occurrence of the partial discharge, when it is determined that the breaking operation is not being executed, the vacuum valve abnormality determination device according to claim 1, wherein the partial discharge is determined as a discharge associated with an abnormality of the vacuum valve.

3. When the determination unit determines that the breaking operation is being executed before the occurrence of the partial discharge and a plurality of the partial discharges occur during a predetermined period, the determination unit determines the continuity of the plurality of partial discharges based on the period from the occurrence of one of the plurality of partial discharges to the occurrence of another one, and determines the presence or absence of an abnormality of the vacuum valve based on the presence or absence of the continuity. The vacuum valve abnormality determination device according to claim 1.

4. The vacuum valve abnormality determination device according to claim 3, wherein the determination unit determines the plurality of partial discharges as non-sustained discharges when there is no continuity among the plurality of partial discharges.

5. When the determination unit determines that there is continuity among the plurality of partial discharges and determines that the number of the partial discharges occurring during the predetermined period is equal to or more than a predetermined number, the determination unit determines the type of abnormality of the vacuum valve. The vacuum valve abnormality determination device according to claim 3.

6. When the determination unit determines that the breaking operation is not being executed before the occurrence of the partial discharge and a plurality of the partial discharges occur during a predetermined period after the partial discharge occurs, the determination unit determines whether or not the interval and the period of the main circuit current are synchronized based on the intervals between the occurrences of the plurality of partial discharges. The vacuum valve abnormality determination device according to claim 1.

7. When the determination unit determines that the interval and the period of the main circuit current are synchronized, the determination unit determines the presence or absence of continuity of a plurality of the partial discharges based on the interval, and determines the types of the plurality of the partial discharges when it is determined that there is continuity among the plurality of the partial discharges. The vacuum valve abnormality determination device according to claim 6.

8. When the determination unit determines that there is no continuity among the plurality of the partial discharges and determines that the number of the partial discharges generated during the predetermined period is equal to or greater than a predetermined number, the determination unit determines the types of the plurality of the partial discharges. The vacuum valve abnormality determination device according to claim 7.

9. When the determination unit determines that a plurality of the intervals and the period of the main circuit current are not synchronized and determines that the number of the partial discharges generated during the predetermined period is equal to or greater than a predetermined number, the determination unit determines the types of the plurality of the partial discharges. The vacuum valve abnormality determination device according to claim 6.

10. A discharge time specifying unit that specifies a discharge time at which the partial discharge has occurred based on the detection of the partial discharge by the discharge detection unit; A cutoff time specifying unit that specifies a cutoff time at which the cutoff operation has occurred based on the detection of the cutoff operation by the cutoff detection unit, and The determination unit determines the presence or absence of an abnormality of the vacuum valve based on whether the cutoff time is before the discharge time. The vacuum valve abnormality determination device according to claim 1.

11. The cutoff detection unit detects the cutoff operation based on a voltage value of a voltage applied to a trip coil of the vacuum circuit breaker. The vacuum valve abnormality determination device according to any one of claims 1 to 10.

12. Detection of partial discharge in a container in which a vacuum valve of a vacuum circuit breaker is stored, Detection of a cutoff operation of a main circuit current by the vacuum circuit breaker, and Determination of the presence or absence of an abnormality of the vacuum valve based on whether the cutoff operation has been executed before the occurrence of the partial discharge. A vacuum valve abnormality determination method including:

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