JPH11250777A - Opening/closing equipment operation diagnosis device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain data close to the original waveform and to perform a highly advanced diagnosis by operating the maximum value and the duration of digital data sent from an external memory device to a programmable controller through a communication means as trend data and by judging the level of the trend data. SOLUTION: When an opening/closing equipment is operated, a current flows in a control circuit 1 to be detected by a current detecting CT2. The detection signal is incorporated in a programmable controller(PC) 4 and an external memory device 5 via a signal converter 3 at a prescribed period. The PC4 operates the current conducting time of the received waveform data and the maximum value of the current by the data processing means of the digital data sent from the external memory device 5 via a communication means 8 and compares them with the preset normal region level. The PC4 judges the presence/absence of the abnormality in the waveform data, based on the comparison results, and stores the waveform data and the judgment results in a data memory means as trend data.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sensor for detecting operating characteristics of a switchgear at a substation, calculating and judging the state of the switchgear based on data obtained from the sensor. The present invention relates to a switching device operation diagnostic device that performs work support.

[0002]

2. Description of the Related Art FIG. 9 is a block diagram showing a conventional switchgear operation diagnostic device disclosed in Japanese Utility Model Laid-Open Publication No. 63-41784. In FIG. 9, a conventional switchgear operation diagnostic device includes a switchgear operation circuit 71, a trip coil 72,
CT (Cu) for detecting the current flowing through the trip coil 72
rent Transformer) 73, CT73
An amplifier 74 for amplifying a current input from the light emitting diode 75, a light receiving element 76 for receiving light from the light emitting diode 75, an optical fiber 77 for transmitting light from the light emitting diode 75, an amplifier 78 for amplifying a signal from the light receiving element 76,
The comparator 79 includes a comparator 79 that detects a voltage change from the rising of the input signal to when the voltage becomes 0 V again and generates a square wave, and an arithmetic processing unit 80 that calculates an energization time for the input square wave. A closed coil may be used instead of the trip coil 72.

Next, the operation will be described. Operation circuit 71
In, a control current flows according to an operation command of the switchgear, and a control current flows through the coil 72. This control current is C
It is detected by T73 and further amplified by the amplifier 74. The light emitting diode 75 emits light according to the amplified signal, and is transmitted as an optical signal by the optical fiber 77. The light receiving element 76 receives an optical signal transmitted by the optical fiber 77, generates a voltage signal based on the optical signal, and the voltage signal is amplified by the amplifier 78. The signal output from the amplifier 78 is input to a comparator 79, which generates a square wave at intervals from the rising of the voltage signal until the voltage becomes 0 V again, and outputs it to the arithmetic processing unit 80. The arithmetic processing unit 80 counts the continuous time of the captured square wave and calculates the energizing time of the control current of the switchgear.

[0004]

The conventional apparatus is configured as described above. When no current actually flows through the trip coil 72, the current flows through the trip coil 72 by the arithmetic processing unit 80. However, when the current actually starts flowing through the trip coil 72,
Although it can be seen that a current flows through the control circuit of the switchgear by the arithmetic processing unit, the current value could not be specifically known. Therefore, the actual current waveform of the control current flowing through the trip coil 72 cannot be captured,
There has been a problem that there is no means for diagnosing the switching device other than the level determination for comparing the energizing time (rise time) of the current signal based on the current waveform with a normal range. In addition, there is a problem that it is impossible to estimate which part of the switchgear has an abnormality and the cause of the abnormality only by determining the level of the power supply time.

The present invention has been made to solve the above-described problems. By combining a general-purpose PC and an external storage device as a diagnostic device, data close to the original waveform can be obtained, and a more advanced diagnostic device can be obtained. It is an object of the present invention to provide a switchgear operation diagnosis device capable of performing the operation.

[0006]

SUMMARY OF THE INVENTION A switching device operation diagnostic apparatus according to the present invention comprises a current detecting means for detecting a current flowing through a control circuit of the switching apparatus, and an analog signal in a predetermined range which is detected by the current detecting means. And a programmable controller that captures and monitors the current output from the signal converter at a first resolution, and outputs a contact signal after a lapse of a predetermined time after the current value exceeds the first level. A relay that outputs a trigger signal from an output terminal when receiving the contact signal from the programmable controller, and is connected to the programmable controller via the communication means and connected to an output terminal of the relay. The signal output from the converter is captured as digital data at a second resolution higher than the first resolution. An external storage device for receiving the signal from the signal converter, suspending the capture of the signal output from the signal converter for a second time, and transmitting digital data to the programmable controller. The processing means calculates the maximum value and the data continuation time of the digital data transmitted from the external storage device to the programmable controller through the communication means as trend data, and determines the level of the trend data.

[0007] The present invention is further characterized by further comprising a data storage means for storing the trend data and the result of the level determination, and a man-machine interface for displaying data stored in the data storage means.

Further, the programmable controller has a function of predicting the arrival of the trend data to an abnormal level based on the trend of change of the trend data over the past several generations.

Further, the programmable controller further includes a contact signal input interface for distinguishing between a rated current interruption of the circuit breaker and an accident current interruption, and the data processing means includes a design life operation number, a rated load interruption number, and And a function for calculating the remaining life of each of the electric motors based on the number of times of fault current interruption.

[0010] Further, the programmable controller stores the digital data fetched from the external storage device into a first data.
In addition to dividing at the resolution of, the integral processing by time is performed for each divided section, the area of each divided section is obtained, and based on the first ratio of the area to the total area, the state of the switchgear and the cause of the failure are identified. It is characterized by having a function of specifying.

[0011] In addition, the above-mentioned integration process extracts the similar ratio by comparing the first ratio of the area of each divided section to the total area with a plurality of abnormal waveform patterns stored in advance, thereby opening and closing the switchgear. It is characterized by grasping the state of the device and identifying the cause of the failure.

Further, the programmable controller obtains a time change rate of the digital data by performing a differentiation process on the digital data captured at the second resolution at each time point divided by the second resolution. 0
It is characterized in that it has a function of grasping the state of the switchgear and specifying a cause part based on the second ratio of the area of the original waveform divided at the point in time to the total area.

[0013] Further, the differential processing is a function of extracting a similar pattern by comparing the second ratio with a plurality of abnormal waveform patterns stored in advance, thereby grasping the state of the switchgear and identifying the cause. It is characterized by having.

[0014] Further, it is characterized by comprising guidance data storage means into which maintenance work information for each switchgear has been input, and display information retrieval means for extracting appropriate guidance based on the determination result of the trend data.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 FIG. 1 is a diagram schematically showing a configuration of a switching device operation diagnosis device according to Embodiment 1 of the present invention. As shown in FIG. 1, a switching device operation diagnostic device according to Embodiment 1 of the present invention includes a control circuit 1 for a switching device, and a C for detecting a control current of the control circuit 1.
T (Current Transformer: current converter) 2, a signal converter 3 for converting a signal from CT2 into a current of 4 to 20 mA, a general-purpose PC (programmable controller) 4 for performing various data processing, a current waveform with high resolution The communication means 8 (R
S-232C format), the external storage device 5 for transmitting the fetched current waveform to the PC 4, and the contact output signal from the PC 4 as a trigger signal for a non-voltage contact.
And a CR for displaying the calculation result and the judgment result in the data processing function of the PC 4
A man-machine interface 7 including a T display device and the like is provided. As shown in FIG. 1, the general-purpose PC 4 has three interfaces (an analog input I / F for inputting an analog signal (hereinafter, the interface is referred to as I / F)) and a relay 6 for transmitting a contact signal. Contact output I
/ F, an RS-232CI / F for receiving a digital signal from the external storage device 5, and a data processing unit,
It comprises a data storage means and a CPU.

Next, the operation of the switching device operation diagnosis apparatus will be described. When a switchgear to be diagnosed operates, a current flows through the control circuit 1, and the control current is detected by a CT2 attached to the device. The weak signal from the CT 2 is output to the signal converter 3 installed near the sensor.
Is converted into an analog signal of 4 to 20 mA as a predetermined range, and is taken in by the PC 4 at a constant period (10 ms corresponding to the first resolution) via the analog input I / F, and similarly in the external storage device 5. (Second
At a 1 ms period corresponding to the resolution of PC
In 4, the captured current is monitored by sampling for several tens of ms, and when the current value exceeds a certain level (for example,
After a sufficient time (for example, 3 to 4 seconds) from when the current rises from 0 mA to when the operation of the switchgear is completed, a pulse-like contact signal is output to the relay 6.

The external storage device 5 stores the constantly taken current data at a high resolution (for example, 1 ms) every cycle of several seconds.
, Writing is performed on the built-in ring memory. When a trigger signal from the relay 6 is received, the writing is suspended and data is temporarily held. Then, the data written on the ring memory of the external storage device 5 is transmitted to the PC 4 via the communication unit 8 that performs communication in the RS-232C format. After the communication with the PC 4 is completed, the external storage device 5 restarts data writing. Therefore, the second time during which the external storage device 5 suspends data writing is set to the external storage device 5.
Is the time from when the trigger signal is received from the relay 6 to when the data transmission to the PC 4 is completed.

In the PC 4, the data processing means for digital data transmitted from the external storage device 5 causes the waveform data received from the external storage device 5 to be energized (the time from the rise of the current waveform until the voltage returns to 0V). And the maximum value of the current are calculated and compared with a normal range level set in advance. Then, the PC 4 determines whether there is an abnormality in the waveform data based on the comparison result, and stores the waveform data and the determination result as trend data in a data storage unit in the PC 4. The man-machine I / F 7 can display necessary data from data storage means in the PC 4 in response to a request from a maintenance person.

As described above, according to the present invention, the waveform data of the control current of the switchgear can be more accurately captured in a form close to the original waveform (the waveform of the current flowing in the control circuit).
Based on this data, it is possible to perform a determination process on the current supply time and the current maximum value, and since necessary data can be displayed from the data storage means in the PC 4 by the man-machine I / F 7, the original waveform It is possible to provide a switching device operation diagnostic device capable of obtaining data close to the above and performing more advanced diagnosis. In the above description, the case where the communication means 8 is of the RS-232C format has been described. However, the same effect can be obtained by using the RS-455C or RS-485C format having higher performance. Can be. In the above description, the case where one external storage device 5 is used has been described, but two or more external storage devices may be used. In such a case, one external storage device 5
From the time when the trigger signal is received until the time when the digital data is transmitted to the PC 4 (second time), even if the writing of the analog data output from the signal converter 3 is suspended, the other external storage devices 5 Since writing of analog data can be performed, it is possible to provide a switching device operation diagnosis device capable of performing a more advanced diagnosis.

Embodiment 2 FIG. 2 is a diagram schematically showing data processing in the switching device operation diagnostic device according to Embodiment 2 of the present invention. In the first embodiment, the data processing means of the PC 4 performs only the level determination process of the current supply time and the current maximum value. However, in the second embodiment of the present invention, in addition to these determination processes, the data generation means of the past several generations is used. It is characterized in that it has a function of predicting the arrival of trend data to an abnormal level based on the changing tendency of the trend data over the period. That is, the PC 4 has a function of determining how many times the operation should be performed and the trend data reaches the abnormal level.

For example, in the data processing method as shown in FIG. 2, even if the trend data does not reach the abnormal level, if the trend data over the past several generations is continuously increasing, a mathematical method ( By using the least squares method, for example, it is possible to inform maintenance personnel of the degree of abnormality by adding a function to determine the number of operations after which the trend data reaches the abnormal level, and to perform maintenance. Can be warned for a long period.

In this way, it is possible to provide a switchgear operation diagnostic apparatus capable of performing a more advanced diagnosis. Although the data processing by the least squares method is shown here, the data processing may be performed by using another mathematical method.

Embodiment 3 FIG. FIG. 3 is a diagram schematically showing a main part of a configuration of a switching device operation diagnosis device according to Embodiment 3 of the present invention. In the second embodiment, the number of times until the abnormal level is reached is calculated based on the trend data. However, in the third embodiment, in addition to the above, the rated current interruption of the circuit breaker and the accident current interruption are distinguished. A contact signal input interface is further provided, and the data processing means is provided with a function of obtaining a remaining life based on the design life operation count, rated load cutoff count, and fault current cutoff count.

For example, as shown in FIG. 3, the PC 4 is provided with a contact signal I / F 32 for receiving a contact signal for distinguishing between no-load operation, rated cutoff, and fault current cutoff from the switchboard 31. The PC 4 counts the number of no-load operations, the number of rated cutoffs, and the number of accident cutoffs in the data processing means in the PC 4, and compares a preset mechanical life and an electric life based on these data. By doing so, it is possible to calculate the remaining life of the switchgear in addition to the operation abnormality detection function of the switchgear described in the first embodiment. In this way, it is possible to provide a switchgear operation diagnosis device capable of performing a more advanced diagnosis.

Embodiment 4 FIG. 4 is a diagram schematically showing data processing in the opening / closing operation diagnosis device according to Embodiment 4 of the present invention, and FIG. 5 is a diagram showing Embodiment 4 of the present invention.
FIG. 6 is a diagram showing a specific example of data processing in the opening / closing operation diagnosis device according to the embodiment. In the first embodiment, the data processing means of the PC 4 only performs the process of determining the current supply time and the level of the current maximum value. However, in the fourth embodiment of the present invention, in addition to these determination processes, The digital data fetched from the storage device 5 is divided at a first resolution (10 ms), and an integral process is performed with respect to each divided section to obtain an area of each divided section. It is provided with a function for grasping the state of the switchgear and identifying the location of the failure based on the ratio.

For example, according to a data processing procedure as shown in FIG. 4, the acquired current data is divided at regular time intervals (for example, 10 ms) as shown in FIG. 5, and integration processing is performed in each section. When the area ratio is obtained based on the integration process corresponding to the passage of time, the area ratio is compared with a plurality of abnormal waveform patterns stored in advance (see FIG. 5), and a similar pattern is extracted to grasp the state of the device. Identify the cause.

As described above, according to the switching operation diagnosing apparatus according to the fourth embodiment of the present invention, in addition to the processing for determining the current conduction time and the maximum current value of the control current shown in the first embodiment, Therefore, it is possible to provide a switchgear device operation diagnosis device capable of performing a more advanced diagnosis.

Embodiment 5 FIG. 6 is a diagram schematically showing data processing in the opening / closing operation diagnostic device according to Embodiment 5 of the present invention, and FIG. 7 is a diagram showing Embodiment 5 of the present invention.
FIG. 6 is a diagram showing a specific example of data processing in the opening / closing operation diagnosis device according to the embodiment. In the switching operation diagnosis apparatus according to Embodiment 5 of the present invention, in addition to the level determination processing of the current supply time and the current maximum value in Embodiment 1, the digital data captured at the second resolution is converted to the second resolution. The time change rate of the digital data is obtained by performing a differentiation process at each time point delimited by, and based on the second ratio of the area of the original waveform divided at the time point at which the time change rate becomes 0 to the entire area, It has a function of grasping the state of the switchgear and identifying the cause.

For example, in accordance with a data processing procedure as shown in FIG. 6, the acquired current data is differentiated, and as shown in FIG. 7, the waveform of the acquired current is changed every time the time change rate (di / dt) becomes zero. Performs integration processing. Based on the result of the integration processing, the area ratio corresponding to the change in the current is obtained (see FIG. 7), and in the same manner as the processing described in the fourth embodiment, comparison with a plurality of abnormal waveform patterns stored in advance is performed. By extracting similar patterns, the state of the device is grasped and the cause is specified.

As described above, according to the switching operation diagnosing apparatus according to the fifth embodiment of the present invention, in addition to the processing for determining the current conduction time and the maximum current value of the control current shown in the first embodiment, Therefore, it is possible to provide a switchgear device operation diagnosis device capable of performing a more advanced diagnosis.

Embodiment 6 FIG. FIG. 8 is a diagram schematically showing a configuration of an opening / closing operation diagnosis device according to Embodiment 5 of the present invention. In the switching operation diagnosis apparatus according to Embodiment 6 of the present invention, in addition to the determination processing by PC 4 in Embodiments 1 to 5, guidance data storage means to which maintenance work information for each switching device is input, A display information search unit for extracting appropriate guidance based on the data determination result is provided, so that maintenance personnel can be notified of appropriate guidance to the equipment.

For example, when the judgment result of the judgment processing means 62 of the data fetched by the data fetching means 61 provided inside the PC 4 as shown in FIG. The command is output, and the corresponding item is extracted from the maintenance, inspection, and recovery support information 65 stored in advance, and the man-machine I / F is extracted.
To be displayed.

As described above, according to the switching operation diagnosing apparatus according to the sixth embodiment of the present invention, maintenance of switching equipment,
By appropriately displaying the inspection and restoration support information, maintenance personnel can be informed of appropriate guidance to the equipment. Therefore, it is possible to provide a switchgear operation diagnostic device capable of performing a more advanced diagnosis.

[0034]

According to the present invention, there is provided a switching device operation diagnosing device for detecting a current flowing in a control circuit of the switching device, and a signal for converting the control current detected by the current detecting device into an analog signal in a predetermined range. A converter, a programmable controller that captures and monitors the current output from the signal converter at a first resolution, and outputs a contact signal after a lapse of a predetermined time after the current value exceeds the first level;
Upon receiving the contact signal from the programmable controller, the relay that outputs a trigger signal from the output terminal is connected to the programmable controller via the communication means and connected to the output terminal of the relay. The signal output from the signal converter is captured as digital data at a second resolution higher than the first resolution, but when a trigger signal is received, the capture of the signal output from the signal converter is paused for a second time. And an external storage device for transmitting digital data to the programmable controller, wherein the data processing means of the programmable controller has a maximum value and a data duration time of the digital data transmitted from the external storage device to the programmable controller through the communication means. Perform as trend data And, since and performing level determination of the trend data, it is possible to obtain data close to the original waveform, it can be performed more operation diagnosis of advanced switching devices on the basis of this data.

Further, since the apparatus further comprises a data storage means for accumulating the trend data and the result of the level judgment, and a man-machine interface for displaying the data stored in the data storage means, In addition, it is possible to provide a switchgear operation diagnostic apparatus that can provide appropriate guidance to the switchgear and perform more advanced diagnosis.

Further, the programmable controller has a function of predicting the arrival of the trend data at an abnormal level based on the trend of the trend data over the past several generations. Understandably, it is possible to provide a switchgear device operation diagnosis device that improves the diagnosis efficiency.

Further, the programmable controller further includes a contact signal input interface for distinguishing between a rated current interruption of the circuit breaker and an accident current interruption, and the data processing means includes a design life operation number, a rated load interruption number, and It has a function to determine the remaining life of each switching device based on the number of times of accident current interruption, so that the remaining life of the switching device can be calculated and more advanced diagnosis can be performed. An apparatus can be provided.

Further, the programmable controller stores the digital data fetched from the external storage device in the first
In addition to dividing at the resolution of, the integral processing by time is performed for each divided section, the area of each divided section is obtained, and based on the first ratio of the area to the total area, the state of the switchgear and the cause of the failure are identified. Since the device is provided with the function of specifying, it is possible to provide a switching device operation diagnosis device capable of performing a more advanced diagnosis.

In the above-mentioned integration processing, the first ratio is compared with a plurality of abnormal waveform patterns stored in advance to extract a similar pattern, thereby grasping the state of the switchgear and identifying the location of the cause of the failure. With this feature, it is possible to provide a switchgear device operation diagnostic apparatus that can accurately grasp the state of the switchgear and the location of the cause of the failure and perform a more advanced diagnosis.

Further, the programmable controller obtains a time change rate of the digital data by performing a differentiation process on the digital data captured at the second resolution at each time point divided by the second resolution. 0
Based on the second ratio of the area of the original waveform divided at the point in time to the total area, the state of the switchgear is provided and the function of identifying the cause is provided, so that a more advanced diagnosis is performed. It is possible to provide a switchgear device operation diagnosis device that can perform the operation.

Further, the differentiation process is a function of extracting the similar pattern by comparing the second ratio with a plurality of abnormal waveform patterns stored in advance, thereby grasping the state of the switchgear and identifying the cause. Therefore, it is possible to provide a switchgear device operation diagnostic apparatus that can grasp the state of the switchgear and the location of the cause of failure accurately, and can perform a more advanced diagnosis.

Further, it is characterized by comprising guidance data storage means into which maintenance work information for each switchgear is inputted, and display information search means for extracting appropriate guidance based on the result of the trend data judgment. In addition, it is possible to provide a switching device operation diagnosis device with further improved diagnosis efficiency.

[Brief description of the drawings]

FIG. 1 is a diagram schematically showing a configuration of a switching device operation diagnostic device according to Embodiment 1 of the present invention;

FIG. 2 is a diagram schematically showing data processing in a switching device operation diagnostic apparatus according to Embodiment 2 of the present invention.

FIG. 3 is a diagram schematically showing a main part of a configuration of a switching device operation diagnosis device according to Embodiment 3 of the present invention;

FIG. 4 is a diagram schematically showing data processing in an opening / closing operation diagnosis apparatus according to Embodiment 4 of the present invention.

FIG. 5 is a diagram showing a specific example of data processing in an opening / closing operation diagnosis device according to Embodiment 4 of the present invention.

FIG. 6 is a diagram schematically showing data processing in an opening / closing operation diagnosis apparatus according to Embodiment 5 of the present invention.

FIG. 7 is a diagram showing a specific example of data processing in an opening / closing operation diagnosis device according to Embodiment 5 of the present invention.

FIG. 8 is a diagram schematically showing a configuration of an opening / closing operation diagnosis device according to Embodiment 5 of the present invention;

FIG. 9 is a block diagram showing a conventional switchgear operation diagnostic device disclosed in Japanese Utility Model Laid-Open No. 63-41784.

[Explanation of symbols]

1 control circuit, 2 CT for current detection, 3 signal converter,
4 PC (programmable controller), 5 external storage device, 6 signal relay, 7 man-machine I /
F, 8 communication means, 31 switchboard, 41 data processing procedure 1, 42 abnormal waveform pattern comparison example, 51 data processing procedure 2, 52 differential processing conceptual diagram, 61 data acquisition means, 62 judgment processing means, 63 trend data, 6
4 display method search means, 65 maintenance, inspection, restoration support information, 71 switching device operation circuit, 72 coil, 73 current detection CT, 74 amplifier, 75 light emitting diode,
76 light receiving element, 77 optical fiber, 78 amplifier,
79 Comparator, 80 operation processing unit.

Claims (9)

[Claims] 1. A current detecting means for detecting a current flowing in a control circuit of a switchgear, a signal converter for converting a control current detected by the current detecting means into an analog signal in a predetermined range, and A programmable controller that captures and monitors the output current at a first resolution, outputs a contact signal after a predetermined time has elapsed since the current value exceeds the first level, and receives the contact signal from the programmable controller. A relay for outputting a trigger signal from an output terminal, connected to the programmable controller via communication means and connected to the output terminal of the relay, and output from the signal converter when the trigger signal is not received. Signal is captured as digital data at a second resolution higher than the first resolution. An external storage device that, when receiving the digital signal, suspends the capture of the signal output from the signal converter for a second time and transmits the digital data to the programmable controller. The data processing means of the programmable controller includes:
Switching device operation diagnosis, wherein the maximum value and the data duration of the digital data transmitted from the external storage device to the programmable controller through the communication means are calculated as trend data, and the level of the trend data is determined. apparatus. 2. The apparatus according to claim 1, further comprising: a data storage unit that stores the trend data, the result of the level determination, and a man-machine interface that displays data stored in the data storage unit. 3. The switching device operation diagnostic device according to claim 1. 3. The programmable controller according to claim 1, further comprising:
The switching device operation diagnostic device according to claim 2, further comprising a function of predicting the trend data reaching an abnormal level. 4. The programmable controller further includes a contact signal input interface for distinguishing between a rated current interruption of the circuit breaker and an accident current interruption, and the data processing means includes a design life operation number, a rated load interruption number, The switching device operation diagnosis device according to claim 2, further comprising a function of obtaining a remaining life of each of the switching devices based on the number of fault current interruptions. 5. The programmable controller divides the digital data fetched from the external storage device at the first resolution, performs an integration process by time for each divided section, and calculates an area for each divided section. The switchgear operation diagnostic device according to claim 2, further comprising a function of determining the state of the switchgear and specifying a failure cause location based on the obtained ratio and the first ratio of the area to the total area. 6. The integration process according to claim 1, wherein the first ratio is compared with a plurality of abnormal waveform patterns stored in advance to extract a similar pattern, thereby grasping the state of the switchgear and identifying a failure cause location. The switching device operation diagnostic device according to claim 5, wherein the operation is performed. 7. The programmable controller obtains a time change rate of the digital data by performing a differentiation process on the digital data captured at the second resolution at each time point divided by the second resolution, The system according to claim 1, further comprising a function of grasping the state of the switchgear and identifying a cause part based on a second ratio of the area of the original waveform divided at the time when the time change rate becomes zero to the entire area. 3. The switching device operation diagnostic device according to 2. 8. The differentiating process extracts the similar pattern by comparing the second ratio with a plurality of abnormal waveform patterns stored in advance, thereby grasping the state of the switchgear and specifying the cause part. The switching device operation diagnosis device according to claim 7, comprising a function. 9. The apparatus further comprises: guidance data storage means into which maintenance work information for each switchgear is inputted; and display information search means for extracting appropriate guidance based on the result of the determination of the trend data. Claim 3
9. The switching device operation diagnostic device according to claim 8.