JP4580712B2 - Relay inspection method and relay inspection device - Google Patents

Description

  The present invention relates to a method for inspecting a relay and an inspection device for the relay.

  If a problem occurs in an underground transmission line for transmitting electric power, there is a risk of causing a power failure, which has a great social impact. Therefore, in general, the underground transmission line system is provided with a failure section detection device that can quickly detect a failure location.

  For example, as an example, an apparatus that divides underground transmission lines into sections of a predetermined length, detects a ground fault current that flows at the time of the failure for each section, and detects a failure of the underground transmission line is known. More specifically, an overcurrent method is used in which a current transformer is installed for each section of the underground transmission line, the output of the current transformer is sent to the detector, and the output (current) is detected and judged by the detector. There is known a failure section detection apparatus based on the above. Usually, the detector consists of a relay.

Such a failure section detection device is very important for stable power supply, early recovery from failure, etc., but if the components of the device do not operate normally due to deterioration etc., malfunction or May cause malfunction. Therefore, the apparatus is normally inspected periodically to ensure normal operation. In addition, although patent document 1 is mentioned about a failure area detection apparatus, for example, the prior literature about the inspection means does not seem to be seen.
JP-A-6-294837

  However, since there are many failure section detection devices to be inspected, and it has conventionally required a lot of time and labor to inspect one device, it is improved from the viewpoint of efficiency or economically. Was demanded.

  The present invention has been made in view of the above-described problems, and the object of the present invention is to inspect a failure section detection apparatus that can be performed in a shorter time and requires less labor. It is to provide means. As a result of repeated studies, it has been found that the above object can be achieved by applying the following relay inspection means. The relay inspecting means according to the present invention is not limited to the inspection of the failure section detecting device, but can be applied to the inspection of the relays provided in all devices and systems.

  That is, according to the present invention, the operation time of the relay is measured when a plurality of test currents each having a predetermined magnification with respect to the operation lower limit current of the relay is input to the relay, and each operation time is set to a specified value. Compared to the above, a relay inspection method for determining the presence or absence of performance degradation is provided (referred to as a first inspection method for a relay, also simply referred to as a first inspection method).

  In the first inspection method for a relay according to the present invention, the plurality of test currents having the predetermined magnification are 150%, 200%, and 300% test currents when the operation lower limit current is 100%. Is preferred. Note that the test current is not limited, and an arbitrary test current in accordance with the timing characteristics of the relay such as 120%, 250%, 350%, etc. can be adopted.

  A first inspection method for a relay according to the present invention is configured such that a current transformer is provided in an underground transmission line, and an output of the current transformer is input to a detector as an electrical signal. As a method for inspecting a relay constituting a detector in a ground fault section detecting device for detecting a ground fault overcurrent input via a current transformer by a detector when a ground fault occurs. Is preferred.

  When the relay constituting the detector is inspected in the underground line fault section detection device, the test current is not limited, but is preferably input from the secondary side of the current transformer.

  Next, according to the present invention, a test current having a predetermined magnification (greater than 1) with respect to the operation lower limit current of the relay is input to the relay for the non-operation guarantee time and the operation guarantee time, respectively. Test the relay to determine the presence or absence of performance degradation by inputting a test current with a predetermined magnification (less than 1) to the relay for the operation lower limit current for the duration of the operation and checking the operation status of each relay. A method is provided (referred to as a second inspection method for a relay, also simply referred to as a second inspection method). The relay inspection method according to the present invention refers to both the first inspection method and the second inspection method. Further, in this specification, the operation required time means a time until the relay operates when a current exceeding the operation lower limit current of the relay is input, and is a time defined for each relay. The non-operation guaranteed time and the operation guaranteed time are a time that is guaranteed not to operate and a time that is guaranteed to operate when a predetermined current is passed, and is a time that is specified for each relay.

  In the second inspection method of the relay according to the present invention, the test current having the predetermined magnification (greater than 1) is a test current of 120% when the operation lower limit current is 100%, and the predetermined magnification The test current having a magnitude of (less than 1) is preferably 80% of the test current when the lower limit operating current is 100%. Note that these are not limited, and other test currents such as 110% and 130%, for example, can be employed as the test current having a magnification larger than 1 with respect to the operation lower limit current. In addition, for example, a test current of 90%, 85%, or the like can be employed as a test current having a magnification with respect to the lower limit current of operation of less than 1.

  When judging the presence or absence of performance degradation by checking the operation status of the relay, the non-operation guarantee time is 33.3 msec, the operation guarantee time is 83.3 msec, and the operation required time is 200 msec, for example. I can do it. That is, for example, a test current having a predetermined magnification (greater than 1) with respect to the operation lower limit current of the relay is input to the relay for 33.3 msec as the non-operation guarantee time and 83.3 msec as the operation guarantee time. In this case, the relay does not operate at 33.3 msec, the relay operates at 83.3 msec, and a test current having a predetermined magnification (less than 1) with respect to the operation lower limit current of the relay is required for the above operation. It can be determined that there is no performance degradation because the relay does not operate when input to the relay for 200 msec as time.

  In the second inspection method for a relay according to the present invention, a current transformer is provided in the underground power transmission line, and the output of the current transformer is converted from an electric signal to an optical signal by the feeder and input to the detector. Detected by the underground line fault section detection device that detects the ground fault overcurrent input through the current transformer and the feeder when a ground fault occurs in the underground transmission line. This is suitable as a method for inspecting a relay constituting the device.

  In the case of inspecting the relay constituting the detector in the above-described underground line fault section detecting device (which performs optical signal conversion), the test current is input from the secondary side of the current transformer, although not limited thereto. It is preferred that

  Next, according to the present invention, a test current output means for outputting a test current having a predetermined magnification with respect to the operation lower limit current of the relay, and an operation for measuring the operation time of the relay when the test current is input to the relay There is provided a relay inspection apparatus comprising time measuring means and performance judging means for judging the presence or absence of performance deterioration by comparing the operating time with a specified value.

  In the inspection device for a relay according to the present invention, the performance judging means includes a display, and the display shows a graph in which one axis is an operation time and the other axis is a test current, and is specified on the graph. This represents the management width indicated by the two curves based on the value, and represents whether or not the operating time measured by the operating time measuring means falls within the management width on the graph with respect to the test current output by the test current output means. Thus, it is preferable that the unit can visually determine the presence or absence of performance degradation.

  The relay inspection device according to the present invention is configured such that a current transformer is provided in the underground transmission line, and the output of the current transformer is input to the detector, and a ground fault has occurred in the underground transmission line. Sometimes, it is suitable as a device for inspecting a relay constituting a detector in a ground fault section detecting device for detecting a ground fault overcurrent input via a current transformer by a detector.

  The first inspection method of the relay according to the present invention measures the operation time of the detector when a plurality of test currents each having a predetermined magnification with respect to the operation lower limit current of the detector is input to the detector, Compared with the specified operating time, the presence or absence of performance degradation is judged, so the test current can be passed for a short time, the time required for inspection can be shortened, and the device that outputs the test current can be downsized. .

  The second inspection method of the relay according to the present invention inputs a test current having a magnitude of a predetermined magnification with respect to the operation lower limit current of the detector, to the feeder for each of the non-operation guarantee time and the operation guarantee time, Since the presence or absence of performance degradation is determined by confirming the operation status of the detector, the time for supplying the test current can be shortened, the time required for the inspection can be shortened, and the apparatus for outputting the test current can be miniaturized.

  The first inspection method for the relay according to the present invention is used when the relay constituting the detector is used as a means for inspecting the relay constituting the detector in the underground line fault section detecting device that does not perform optical signal conversion. When the second inspection method is used as a means for inspecting the relay constituting the detector in the underground line fault section detecting apparatus that performs optical signal conversion, preferably, the test current is preferably the current of the current transformer. Since it is input from the secondary side, the magnitude of the test current becomes smaller. Therefore, the device that outputs the test current can be miniaturized. Since the test current reaches the detector from the secondary side of the current transformer via the electric signal line to the optical signal line (optical fiber), the entire fault section detection device including the system is simultaneously inspected. It will be. In the conventional inspection method, the test current is input from the primary side of the current transformer, and the test current is passed for a long time at the magnitude of the operation lower limit current of the detector, so the test current is output. The equipment to be used has become large and requires a lot of manpower.

  The relay inspection device according to the present invention plays the role of a device that outputs the test current. However, the device is downsized and improved in portability based on the effect of the relay inspection method according to the present invention. Further, the relay inspection apparatus according to the present invention preferably enables visual determination of the presence or absence of performance degradation, so that the determination is easy and does not require skilled skills for the person performing the inspection. Therefore, it is not necessary to train specialists who are only inspected, and in combination with the improvement in portability, the efficiency of personnel can be improved.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings as appropriate. However, the present invention should not be construed as being limited to these, and those skilled in the art will be able to do so without departing from the scope of the present invention. Various changes, modifications and improvements can be made based on the knowledge. For example, the drawings show preferred embodiments of the present invention, but the present invention is not limited by the modes shown in the drawings or the information shown in the drawings. In practicing or verifying the present invention, means similar to or equivalent to those described in the present specification can be applied, but preferred means are those described below.

  First, a first inspection method for a relay according to the present invention will be described. FIG. 1 is a diagram for explaining the first inspection method, and is a configuration diagram showing an example of an underground line fault section detecting device in which a relay is used as a detector. The underground fault section detecting device 10 is configured such that a current transformer 12 is provided in the underground power transmission line 11, and an output of the current transformer 12 is input to a detector 13 (relay) as an electrical signal. When a ground fault occurs in the underground power transmission line 11, a ground fault overcurrent is input to the detector 13 via the current transformer 12, and it is detected that a ground fault has occurred. The detector 13 is configured as a relay that operates according to the magnitude of an electrical signal (current).

  FIG. 6 is a circuit block diagram showing an example of the detector 13 (relay). For example, the detector of the circuit block shown in FIG. 6 can be adopted as the detector 13. In FIG. 6, the output (secondary side) of the current transformer 12 is connected to the A1 and A2 terminals, and the current corresponding to the current transformation ratio of the current transformer 12 is detected by the detector 13 when the ground fault of the underground power transmission line occurs. Is input. The input current is converted to a current suitable for the internal circuit by the auxiliary current transformer, and is full-wave rectified by the next rectifier circuit to become a DC voltage proportional to the ground fault current. The DC voltage drives the failure indicator (30F) and the ground fault overcurrent relay (17G) with a certain time delay by the time limit circuit, displays that a ground fault has been detected and outputs it to the outside. The return circuit is a circuit for returning the failure indicator (30F) and the ground fault overcurrent relay (17G).

  By inspecting the detector 13, the underground line fault section detecting device 10 can be inspected. Here, for example, 150%, 200%, and 300% of the test current when the operation lower limit current is set to 100% with respect to the operation lower limit current of the detector 13 from the primary side or the secondary side of the current transformer 12. input. Although not limited, the input from the secondary side is preferable. Then, the test current is input to the detector 13 via the electric signal line 14, and here, the operation time of the detector 13 for each test current is measured. Then, each measured operation time is compared with a specified value to determine the presence or absence of performance degradation. The specified value may be a design operation time or may be a time in which an allowable error is added to the design operation time.

  FIG. 4 is a graph showing the relationship between the operation time of the detector 13 (relay) and the test current in the underground line fault section detection device 10. The specified values are the lower limit value of the operating range and the upper limit value of the non-operating range indicated by the curves 41 and 42, and the management width between the curves 41 and 42 is 150%, 200%, 300% as described above. In other words, the plots 43, 44, and 45 obtained by each test current and each operation time are curves on the graph of FIG. If it is between 41 and 42, it is judged that there is no performance degradation. On the contrary, if the management width between the curves 41 and 42 does not include the relationship between the test currents of 150%, 200%, and 300% described above and the operation time of the detector for each, in other words, If the plots 43, 44 and 45 obtained by the test current and each operation time are out of the curves 41 and 42 on the graph of FIG. 4, it is determined that there is performance degradation. Accordingly, if each test current and each operation time are accurately measured, the test current is not 150%, 200%, 300% when the operation lower limit current is set to 100%, for example, and any arbitrary value in the vicinity thereof. It may be a current of value.

  The example shown in FIG. 1 is an overcurrent type underground line fault section detecting device, but the first inspection method for the relay according to the present invention is a differential type underground line shown in FIG. Application to a fault zone detection device is also possible. The underground line fault section detecting device 90 is provided with current transformers 12 at both ends of the section to be detected by the underground power transmission line 11, and outputs of the respective current transformers 12 are detected as electrical signals by detectors 13 (relays). It is comprised so that it may be input. When the detector is provided in the vicinity of one of the current transformers, the output (electric signal) of the other current transformer is sent via the feeder 15. When a ground fault occurs in the underground transmission line 11, a ground fault overcurrent is input to the detector 13 via each current transformer 12, and a ground fault occurs depending on the magnitude of the current value difference as an electric signal. Is detected.

  Next, the 2nd inspection method of the relay concerning the present invention is explained. FIG. 2 is a diagram for explaining the second inspection method, and is a configuration diagram showing another example of the underground line fault section detection device in which the relay is used as a detector. In the underground line fault section detecting device 20, the current transformer 12 is provided in the underground power transmission line 11, and the output of the current transformer 12 is input to the feeder 25 via the electric signal line 14, and the feeder 25, the electric signal is converted into an optical signal and input to the detector 23 (relay) via the optical signal line 26 (optical fiber). When a ground fault occurs in the underground transmission line 11, a ground fault overcurrent is input to the detector 23 via the current transformer 12 and the feeder 25, and it is detected that a ground fault has occurred. The feeder 25 can be configured as a converter from an electrical signal to an optical signal and is not limited. The detector 23 can be configured as a relay that operates according to the magnitude of the optical signal, and is not limited.

  FIG. 7 is a circuit block diagram showing an example of a feeder that can be used as the feeder 25 in the underground line fault section detecting device 20 of the system for transmitting an optical signal, and is a current transformer (ZCT, FIG. 2). The ground fault current (electrical signal) input via the current transformer 12 is converted into an optical signal and output to the detector. In FIG. 7, the input ground fault current is converted into a current suitable for an internal circuit by an auxiliary current transformer (Aux.CT), and after the waveform is shaped by a filter, it is converted by a half-wave rectification (circuit). Half-wave rectified. The half-wave rectified current waveform is converted into a pulse signal having a frequency proportional to the magnitude of the current by a VFC (voltage / frequency conversion circuit), and further converted into an optical pulse signal by an EO conversion (circuit). It is output to the detector as an FD (ground line fault section detection device) signal. The optical coupler uses an FD signal to send back the disconnection monitoring optical pulse signal transmitted from the detector to the detector for disconnection monitoring of the optical transmission line (corresponding to the optical signal line 26 in FIG. 2). Is to be combined. A part of the current converted by the auxiliary current transformer (Aux. CT) is supplied to each internal circuit as a power source necessary for the internal circuit operation by the stabilized power source (circuit).

  FIG. 8 is a circuit block diagram showing an example of a detector that can be employed as the detector 23 (relay) of the underground cable fault section detection device 20, and outputs from a plurality of metering devices (optical pulse signals). This is a detector that can input a FD signal. First, the input optical pulse signal is converted into an electrical signal by OE conversion (circuit) and sent to a counter and disconnection detection (circuit). The optical pulse signal (FD signal) converted into an electric signal is counted by a counter, and the value is transferred to the CPU. When the CPU that has received the count value of the optical pulse signal is greater than the current and the phase difference detection level set in advance by the current and phase difference detection level setting (unit), a ground fault has occurred. It is interpreted, and it is determined from the current value from the feeder and the phase difference between them that there is a ground fault in the judgment section (underground section) for the feeder. When it is determined that there has been a ground fault, it is displayed on the operation display (circuit), and FD detection information is output to the outside through the relay contact (X1). A disconnection monitoring pulse signal (electrical signal) is transmitted from the CPU, which is converted into an optical pulse signal by EO conversion (circuit), and is further output to a feeder by an optical coupler. When the optical pulse signal sent back from the feeder is interrupted for a certain period of time, it is determined by the disconnection detection (circuit) and timer that the optical transmission path (optical signal line) has been disconnected, and the relay contact (X2) Information on disconnection detection is output to the outside. The watchdog timer monitors the operation status of the CPU, and if an abnormality occurs, information on the system abnormality is output to the outside through the relay contact (X3).

  By inspecting the detector 23, the underground line fault section detecting device 20 can be inspected. Here, with respect to the operation lower limit current of the detector 23, for example, a test current of 120% when the operation lower limit current is assumed to be 100% is 33.3 msec as the non-operation guarantee time, and 83.3 msec as the operation guarantee time, Input from the primary side or secondary side of the current transformer 12. Although not limited, the input from the secondary side is preferable. Then, the test current is input to the feeder 25 via the electric signal line 14 and converted into an optical signal, and further input to the detector 23 via the optical signal line 26.

  In addition, 33.3 msec as the non-operation guarantee time and 83.3 msec as the operation guarantee time are times corresponding to 2 cycles and 5 cycles of the power frequency in western Japan. That is, since the frequency is 60 Hz in the West Japan region, 1 cycle is 1/60 = 16.66 msec, 2 cycles are 33.3 msec, and 5 cycles are 83.3 msec. Of course, in the East Japan region, since the frequency is 50 Hz, 1 cycle is from 1/50 = 20 msec, 2 cycles are 40 msec, and 5 cycles are 100 msec. These times are defined as non-operation guarantee time and operation guarantee time. Can be adopted.

  Further, for example, 80% of the test current when the operation lower limit current is set to 100% with respect to the operation lower limit current of the detector 23 is a time (for example, 200 msec) defined as the operation required time of the detector 23 (relay). Input from the primary side or secondary side of the current transformer 12. Although not limited, the input from the secondary side is preferable. Then, the test current is input to the feeder 25 via the electric signal line 14 and converted into an optical signal, and further input to the detector 23 via the optical signal line 26.

  FIG. 5 is a graph showing the relationship between the operating time of the detector 23 (relay) and the test current in the underground line fault section detection device 20. When 120% of the test current is applied for 83.3 msec (plot 53 in the graph), when the detector 23 is operated and 120% of the test current is applied for 33.3 msec ( When the detector 54 does not operate when the plot 54) in the graph and the test current of 80% are supplied for 200 msec (plot 55 in the graph), it is determined that there is no performance degradation. If this condition is not met, that is, when 120% test current is applied for 83.3 msec (plot 53 in the graph), detector 23 does not operate or 120% test current is applied. When the detector 23 is operated either when flowing for 33.3 msec (plot 54 in the graph) or when 80% of the test current is applied for 200 msec (plot 55 in the graph). It is judged that there is performance degradation. In FIG. 5, the operation value management width means a management width of the operation lower limit current that is the minimum value of the input current that operates by continuous input. The operation time management width means a management width of the lower limit value of the input time that operates by instantaneous input.

  The example shown in FIG. 2 is an overcurrent type underground line fault section detecting device, but the second inspection method of the relay according to the present invention is a phase comparison type underground line shown in FIG. Application to a fault zone detection device is also possible. The underground line fault section detecting device 100 is provided with current transformers 12 at both ends of the section to be detected by the underground power transmission line 11, and the outputs of the respective current transformers 12 are respectively connected via the electric signal lines 14. It is configured to be input to the metering device 25, converted from an electric signal to an optical signal by each metering device 25, and input to the detector 23 (relay) via the optical signal line 26 (optical fiber). ing. When a ground fault occurs in the underground transmission line 11, the ground fault overcurrent is input to the detector 23 via the current transformer 12 and the feeder 25, and the phase difference between the currents converted into the optical signal is detected. Thus, it is detected that a ground fault has occurred.

  Next, the relay inspection apparatus according to the present invention will be described. This inspection device is provided with a current transformer in the underground transmission line, and the output of the current transformer is configured to be input to the detector, whether it is an electric signal or converted into an optical signal. When the ground fault occurs in the underground transmission line, the relay constituting the detector is inspected in the ground fault section detecting device that detects the ground fault overcurrent input via the current transformer by the detector. It is suitable as a device.

  The relay inspection apparatus according to the present invention is an apparatus for realizing the relay inspection method according to the present invention. For this purpose, a test current output means for outputting a test current having a predetermined magnification (for example, 120%, 150%, 200%, 300%, etc. when the operation lower limit current is 100%) with respect to the operation lower limit current of the relay. Is provided. As described above, in the relay inspection method (first inspection method) according to the present invention, the test current is not 150%, 200%, 300%, for example, when the operation lower limit current is 100%, A current having an arbitrary value in the vicinity thereof may be used. Therefore, the test current output means does not require the accuracy of the output current value, and the inspection apparatus can be further downsized. The relay inspection apparatus according to the present invention further includes an operation time measuring means for measuring the operation time of the relay when a test current is input to the relay.

  Furthermore, the relay inspection apparatus according to the present invention includes performance determining means for comparing the operating time with a specified value to determine whether or not the relay has deteriorated in performance. A preferred embodiment of this performance judgment means is, for example, a liquid crystal display, and the display represents a graph with the vertical axis representing the operating time and the horizontal axis representing the test current, and the specified value is indicated on the graph. Whether the relay operating time measured by the operating time measuring means with respect to the test current output by the test current output means falls within the management width on the graph. Can be expressed. This visual expression makes it possible to determine the presence or absence of performance degradation.

  FIG. 3 is a circuit block diagram showing an embodiment of a relay inspection apparatus according to the present invention. The control of each circuit is all performed by the CPU. The CPU performs display information on the display (liquid crystal), DAC (digital-analog) according to the operation of each switch of measurement start, display switching, mode switching, and tap switching. The output current waveform signal to the converter circuit is generated and transmitted to each. The digital signal of the output current waveform produced by the CPU is converted to an analog signal by the DAC, then converted to an AC constant current by the power amplifier, and is output as a test current from the current outputs (terminals) k and l. The peak value of the output test current is held by the peak holder. The held peak value is converted into a digital signal by an ADC (analog-digital conversion circuit) inside the CPU, and is taken into the CPU as an output current value. Further, the contact input (information) of the detector input from the contact inputs (terminals) B1 and B2 is converted into an electric signal and taken into the CPU. In the CPU, the time limit characteristic of the relay (detector) is calculated from the output test current and the input contact input (information), and the quality is determined. The display (liquid crystal) displays information necessary for operation, such as operation explanation, setting contents, output current value, and timed measurement value, and measurement results under the control of the CPU. The regulator is a power supply circuit that supplies a stable voltage necessary for each circuit operation, and a voltage (AV) for current output and a voltage (DV) for each circuit are supplied from a battery.

  Further, for example, as a content and design of a graph displayed on a liquid crystal display, a graph having a design shown in FIG. FIG. 11 is a display example of the results measured by the relay inspection apparatus, where the vertical axis represents the operating time (ms) and the horizontal axis represents the test current (%) expressed as a percentage of the operating lower limit current. In FIG. 11, the solid line indicates an approximate curve connecting the operation times of each (three points) measured at test currents of 150%, 200%, and 300% of the operation lower limit current, and the dotted lines above and below the solid line are the test lines. It is an approximate curve which shows the operation | movement lower limit and non-operation upper limit of the operation time (ms) with respect to electric current (%), and represents the management width. Note that the approximate curve indicated by the dotted line can vary depending on the time-limit characteristic of the relay (detector). The 50 ms characters shown in the upper right in FIG. 11 indicate that this display example is, for example, 300% of the lower limit operating current. It is shown that this is an approximate curve in the case of a relay having a time-limiting characteristic with an operation time of 50 ms when the test current is input.

  INDUSTRIAL APPLICABILITY The relay inspection method and relay inspection device of the present invention are suitable as a relay inspection unit used in a detector according to a fault section detection device for underground power transmission lines.

It is a block diagram which shows an example of a underground line fault area detection apparatus. It is a block diagram which shows the other example of a underground line fault area detection apparatus. It is a circuit block diagram which shows one Embodiment of the inspection apparatus of the relay which concerns on this invention. It is a graph showing the relationship between the operating time of a relay for explaining the 1st inspection method of the relay concerning the present invention, and a test current. It is a graph showing the relationship between the operating time of a relay for explaining the 2nd test | inspection method of the relay which concerns on this invention, and a test current. It is a circuit block diagram which shows an example of a relay. It is a circuit block diagram which shows an example of a feeder. It is a circuit block diagram which shows an example of a relay. It is a block diagram which shows the other example of a underground line fault area detection apparatus. It is a block diagram which shows the other example of a underground line fault area detection apparatus. It is a top view which shows one Embodiment of the indicator which comprises a performance judgment means in the inspection apparatus of the relay which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10,20,90,100 ... Underground fault section detection device, 11 ... Underground power transmission line, 12 ... Current transformer, 13, 23 ... Detector, 14 ... Electric signal line, 15, 25 ... Feeder, 26: Optical signal line.

Claims (3)

The current transformer is provided in the ground transmission lines, the output of the current transformer so as to be input to the detector as an electric signal without performing optical signal conversion, when a ground fault occurs in the underground transmission lines And an inspection method for a relay constituting the detector for detecting a ground fault overcurrent input via the current transformer,
A plurality of test current having a magnitude of a predetermined ratio with respect to the minimum operating current of the relay, from the secondary side of the current transformer measures the relay operating time when the input to relay each, each of the operation A relay inspection method for comparing the time with a specified value to determine whether the relay has performance degradation. It is an apparatus used for the inspection method of the relay according to claim 1,
A test current output means for outputting a test current having a predetermined magnification with respect to the operation lower limit current of the relay; an operation time measuring means for measuring the operation time of the relay when the test current is input to the relay; and the operation A relay inspection apparatus comprising: performance determination means for determining whether there is performance degradation by comparing time with a specified value. The performance judging means includes a display,
In addition to representing a graph with one axis as the operating time and the other axis as a test current on the display, the management width represented by two curves based on the specified value on the graph is represented,
For the test current output by the test current output means, the operation time measured by the operation time measurement means represents whether or not the management width on the graph is included,
The relay inspection apparatus according to claim 2, wherein the presence or absence of performance deterioration can be visually determined.

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