Partial discharge signal detection system, diagnostic system, partial discharge signal detection method and detection device

Abstract

To provide a partial discharge signal detection system, a diagnostic system, a partial discharge signal detection method, and a detection device capable of detecting a partial discharge signal corresponding to the cycle of AC power.SOLUTION: A measuring device according to an embodiment includes a partial discharge sensor, a sampling unit, and a transmitting unit. The partial discharge sensor measures a partial discharge signal emitted from a power device. The sampling unit samples a measured value at a first period to generate a time series of discharge signal values. The transmitting unit transmits the time series of discharge signal values. According to an embodiment, an extraction device comprises a power input unit, a period calculation unit, a reception unit, and an extraction unit. The power input unit receives AC power from an AC power source supplying to the power equipment. The period calculation unit calculates a period of the AC power. The reception unit receives the time series of discharge signal values from the measuring device. Based on the calculated period and the first period, the extraction unit extracts a partial time series related to an integral multiple of the period of the AC power from the time series of the discharge signal values.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] SUMMARY OF THE DISCLOSURE Embodiments of the present invention relate to a partial discharge signal detection system, a diagnostic system, a partial discharge signal detection method and an apparatus. [Background technology]

[0002] As electric power equipment deteriorates over time, the insulating performance of the insulators on the surface and inside of the equipment decreases. Partial discharge occurs in the areas where the insulating performance has decreased. If the deterioration of the insulating performance progresses, there is a possibility that the electric power equipment will suffer a dielectric breakdown. Therefore, in order to monitor the condition of the electric power equipment, partial discharge signals generated by the electric power equipment are measured and condition diagnosis is performed based on the partial discharge signals.

[0003] It is known that partial discharges are correlated with the voltage phase of AC power supplied to electric power equipment. Therefore, in order to diagnose the condition of electric power equipment based on partial discharge signals, it is desirable to detect partial discharge signals corresponding to the cycle of AC power.

[0004] A measuring device that is attached to power equipment and measures partial discharge signals and a diagnostic device that performs condition diagnosis based on the measured partial discharge signals may be provided separately. In this case, the diagnostic device needs to identify the relationship between the partial discharge signal received from the measuring device and the voltage phase of the AC power. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2015 / 190260 Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present invention is to provide a partial discharge signal detection system, a diagnostic system, a partial discharge signal detection method, and a detection device that are capable of detecting a partial discharge signal corresponding to a period of AC power. [Means for solving the problem]

[0007] A partial discharge signal detection system according to an embodiment includes a measurement device and an extraction device. The measurement device is attached to an electric power device and measures a partial discharge signal. The extraction device extracts a partial time series corresponding to a period of AC power supplied to the electric power device from a time series of measurement values ​​of the partial discharge signal measured by the measurement device. The measurement device includes a partial discharge sensor, a sampling unit, and a transmission unit. The partial discharge sensor measures a partial discharge signal emitted from the electric power device. The sampling unit generates a time series of discharge signal values ​​by sampling the measurement values ​​by the partial discharge sensor at a first period. The transmission unit transmits the time series of discharge signal values. The extraction device includes a power input unit, a period calculation unit, a receiving unit, and an extraction unit. The power input unit receives AC power from a power source of the AC power supplied to the electric power device. The period calculation unit calculates the period of the AC power. The receiving unit receives the time series of discharge signal values ​​from the measurement device. The extractor extracts a partial time series relating to a time that is an integer multiple of the period of the AC power, from the time series of the discharge signal values, based on the calculated period and the first period. [Brief description of the drawings]

[0008] [Figure 1] 1 is a schematic diagram showing the configuration of a diagnostic system according to an embodiment. [Diagram 2] FIG. 1 is a schematic diagram showing the configuration of a measurement apparatus according to an embodiment. [Diagram 3] 1 is a schematic diagram showing the configuration of a diagnostic device according to an embodiment. [Figure 4] 5 is a diagram showing the relationship between a voltage signal and a reference voltage according to the embodiment. [Diagram 5] 5 is a flowchart showing the operation of a computer of the measurement apparatus according to the embodiment. [Figure 6] 4 is a flowchart showing the operation of a computer of the diagnostic device according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] A partial discharge signal detection system, a diagnosis system, a partial discharge signal detection method, and a detection device according to embodiments will be described below with reference to the drawings. Fig. 1 is a schematic diagram showing a configuration of a diagnostic system 100 according to an embodiment. The diagnostic system 100 detects a partial discharge signal of a target electric power device 200 and diagnoses the state of the target electric power device 200. The target electric power device 200 is, for example, an electric power device such as a transformer or a rotating machine. The diagnostic system 100 is an example of a partial discharge signal detection system. The target electric power device 200 includes a box 210 and a device body 220. The device body 220 is housed in the box 210 which is grounded.

[0010] The diagnostic system 100 includes a measuring device 110 and a diagnostic device 150. The measuring device 110 is attached to a box 210 of a target electric power device 200. The measuring device 110 measures a potential formed on a surface of the box 210 via a stray capacitance between the measuring device 110 and an equipment body 220 housed in the box 210. The diagnostic device 150 diagnoses a state of the target electric power device 200 based on a measurement value of the measuring device 110. Note that one diagnostic device 150 may obtain measurement values ​​from a plurality of measuring devices 110 and diagnose the states of a plurality of target electric power devices 200.

[0011] FIG. 2 is a schematic diagram showing the configuration of a measuring device 110 according to the embodiment. The measuring device 110 includes a partial discharge sensor 111, a data generating circuit 112, a computer 113, and a wireless communication device 114. The measuring device 110 is powered by a battery for the sake of simplicity of configuration.

[0012] The partial discharge sensor 111 measures the potential formed on the surface of the box 210. The partial discharge sensor 111 generates an analog signal corresponding to the measured potential. The partial discharge sensor 111 is, for example, a transient ground voltage detection sensor.

[0013] The data generation circuit 112 quantizes the partial discharge signal based on the analog signal output by the partial discharge sensor 111. The partial discharge sensor 111 and the data generation circuit 112 are connected via a coaxial cable or the like. The data generation circuit 112 includes an amplifier circuit 121, a filter circuit 122, an AD conversion circuit 123, and a clock circuit 124. The amplifier circuit 121 amplifies the analog signal output by the partial discharge sensor 111. The amplifier circuit 121 is realized by a low noise amplifier. The filter circuit 122 removes unnecessary high frequency signals by passing a signal having a frequency equal to or less than half the frequency of the clock signal of the clock circuit 124. In other words, the filter circuit 122 is a low pass filter. The AD conversion circuit 123 quantizes the signal output by the filter circuit 122 at a timing according to the clock signal output by the clock circuit 124. The clock circuit 124 outputs a clock signal at a first frequency. If the period of the clock signal output by the clock circuit 124 is defined as a first period, the AD conversion circuit 123 outputs a measurement value of the partial discharge signal quantized for each first period. Hereinafter, the measurement value (sample) of the partial discharge signal is also referred to as a discharge signal value.

[0014] The computer 113 includes a processor 131 , a main memory 132 , a storage 133 , a DMA controller 134 , and an interface 135 . The processor 131 reads out the measurement program from the storage 133, loads it in the main memory 132, and executes the above-mentioned processing according to the measurement program. The processor 131 also secures storage areas corresponding to the above-mentioned storage units in the main memory 132 according to the measurement program. Examples of the processor 131 include a CPU (Central Processing Unit), a GPU (Graphic Processing Unit), and a microprocessor.

[0015] The DMA controller 134 records the discharge signal values ​​generated by the data generation circuit 112 in sequence in the main memory 132 in accordance with instructions from the processor 131. The processor 131 sets the data transfer address of the DMA controller 134 and the transfer size of data transmission by the wireless communication device 114. The interface 135 converts data for transmission between the peripheral devices. The data generating circuit 112 and the wireless communication device 114 are connected to the computer 113 via the interface 135.

[0016] The wireless communication device 114 transmits the time series of the discharge signal values ​​to the diagnostic device 150 by wireless communication based on a transmission instruction from the computer 113. The wireless communication device 114 performs a framing process involving data division of the time series of the discharge signal values ​​and addition of a header based on a protocol related to wireless communication. The wireless communication device 114 transmits the framed time series of the discharge signal values ​​by a predetermined communication method. The wireless communication device 114 is an example of a transmitting unit.

[0017] FIG. 3 is a schematic diagram showing the configuration of a diagnostic device 150 according to an embodiment. The diagnostic device 150 includes a transformer 151 , a power supply circuit 152 , a sample number calculation circuit 153 , a wireless communication device 154 , and a computer 155 .

[0018] The transformer 151 receives power from the same external AC power source as the target power device 200, and outputs stepped-down power. The transformer 151 is an example of a power input unit. The power supply circuit 152 converts the power output by the transformer 151 into direct current and supplies it to each processing unit of the diagnostic device 150 .

[0019] The sample number calculation circuit 153 analyzes the power waveform output by the transformer 151 and calculates the number of samples corresponding to one period of AC power in the time series of the discharge signal value by the measuring device 110. The sample number calculation circuit 153 includes an AD conversion circuit 161, a clock circuit 162, a cross detection circuit 163, a counter circuit 164, a multiplication circuit 165, and a division circuit 166. The AD conversion circuit 161 quantizes the voltage signal output by the transformer 151 at a timing according to the clock signal output by the clock circuit 162. The clock circuit 162 outputs a clock signal at a second frequency. If the period of the clock signal output by the clock circuit 162 is the second period, the AD conversion circuit 161 quantizes the voltage signal for each second period. Hereinafter, the quantized voltage signal is referred to as a voltage value. The AD conversion circuit 161 is an example of a sampling unit.

[0020] The cross detection circuit 163 monitors the voltage value generated by the AD conversion circuit 161 and detects whether the voltage value is equal to or lower than a predetermined reference voltage V ref Less than the reference voltage V ref The first timing when the voltage exceeds the reference voltage V ref From the above, the reference voltage V ref 4 shows a voltage signal and a reference voltage V ref 1 is a diagram showing the relationship between the reference voltage V and the reference voltage V. The counter circuit 164 counts the number of clocks from the first timing t1 to the second timing t2 and the number of clocks from the second timing t2 to the next first timing t3 based on the clock signal output by the clock circuit 162. The counter circuit 164 outputs the sum of the number of clocks from the first timing to the second timing and the number of clocks from the second timing to the next first timing as the count number related to one cycle of the power supply. ref is set to a value within the minimum range in one period of the voltage signal. Counter circuit 164 is an example of a period calculation section. The multiplication circuit 165 multiplies the count number calculated by the counter circuit 164 by the period (second period) of the clock signal of the clock circuit 162. This calculation is equivalent to dividing the count number by the second frequency. The division circuit 166 divides the count number output by the multiplication circuit 165 by the period (first period) of the clock signal of the clock circuit 124. This calculation is equivalent to multiplying the count number by the first frequency. The division circuit 166 outputs the integer part of the calculation result. The output result of the division circuit 166 is the number of samples corresponding to one period of the AC power in the time series of the discharge signal value from the measuring device 110.

[0021] The wireless communication device 154 receives a frame storing a time series of discharge signal values ​​from the measuring device 110 via wireless communication, performs a deframing process involving removing a header and combining data, and outputs the obtained time series of discharge signal values ​​to the computer 155. The wireless communication device 154 is an example of a receiving unit.

[0022] The computer 155 includes a processor 171 , a main memory 172 , a storage 173 , a DMA controller 174 , and an interface 175 . The processor 171 reads the diagnostic program from the storage 173, loads it in the main memory 172, and executes the above-mentioned processing in accordance with the diagnostic program. The processor 171 also secures storage areas in the main memory 172 corresponding to the above-mentioned storage units in accordance with the diagnostic program.

[0023] The DMA controller 174 records the time series of the discharge signal values ​​received by the wireless communication device 154 in the main memory 172 according to instructions from the processor 171 . The interface 175 converts data for transmission between the peripheral devices. The sample number calculation circuit 153 and the wireless communication device 154 are connected to the computer 155 via the interface 175.

[0024] Furthermore, the processor 171 extracts a partial time series relating to N times the period of the AC power from the time series of the discharge signal values ​​recorded in the main memory 172, and diagnoses the state of the target electric power device 200 based on the partial time series, where N is an integer equal to or greater than 1.

[0025] FIG. 5 is a flowchart showing the operation of the computer 113 of the measuring device 110 according to the embodiment. The processor 131 calculates the number of samples of the discharge signal value recorded in the main memory 132 by the DMA controller 134 (step S1). The processor 131 determines whether the number of samples of the discharge signal value recorded in the main memory 132 is equal to or greater than a pre-calculated transmission threshold (step S2). The transmission threshold is calculated by the following formula (1).

[0026]

number

[0027] In formula (1), D th is the transmission threshold. T 0,n is the rated value of the period of the AC power supplied to the target power device 200. 1,n is the rated value (first period) of the period of the clock circuit 124. err is the nominal error of the AC power, and is the nominal error f 1,err , the nominal error f 2,err For example, the margin number D err is set to satisfy the following conditions:

[0028]

number

[0029] The number of samples of the discharge signal value is the transmission threshold D th If the number of samples of the discharge signal value is not equal to or greater than the transmission threshold D (step S2: NO), the monitoring of the number of samples of the discharge signal value is continued. thIf it is equal to or greater than this (step S2: YES), the processor 131 outputs an instruction to the DMA controller 134 to transmit the time series of discharge signal values ​​recorded in the main memory 132 to the wireless communication device 114 (step S3). The DMA controller 134 deletes the time series of discharge signal values ​​transmitted to the wireless communication device 114 from the main memory 132. The processor 131 also outputs an instruction to the wireless communication device 114 to transmit the time series of discharge signal values ​​to the diagnostic device 150 (step S4). As a result, the wireless communication device 114 transmits the time series of discharge signal values ​​to the diagnostic device 150 by wireless communication. Note that the transmission threshold D th is determined based on the nominal error of the AC power, so even if the period of the AC power fluctuates, the time series of the transmitted discharge signal values ​​will be a time series relating to a period at least longer than N periods.

[0030] FIG. 6 is a flowchart showing the operation of the computer 155 of the diagnostic device 150 according to the embodiment. The processor 171 outputs an instruction to the DMA controller 174 to record the time series of the discharge signal values ​​received by the wireless communication device 154 in the main memory 172 (step S21). Next, the processor 171 acquires the number of samples for one cycle of the AC power supply from the sample number calculation circuit 153 (step S22). The acquired number of samples is the number of samples calculated by the sample number calculation circuit 153 for the cycle immediately before the reception of the time series of the discharge signal values. The number of samples D0 calculated by the sample number calculation circuit 153 is given by the following formula (3).

[0031]

number

[0032] In equation (3), C is the count value output by counter circuit 164. The count value C is expressed by the following equation (4).

[0033]

number

[0034] T0 is the actual period of the AC power, and T2 is the period (second period) of the clock circuit 162. From the above formulas (3) and (4), it can be seen that the number of samples D0 is almost the same as the number of samples when the AC power with period T0 is sampled in the first period. Note that the error in the period of the AC power is significantly larger than the error in the period of the clock circuit.

[0035] The processor 171 reads the D th A partial time series consisting of N×D0 discharge signal values ​​is extracted from a time series consisting of N discharge signal values ​​(step S23). The processor 171 is an example of an extraction unit that extracts a partial time series. The processor 171 divides the extracted partial time series into N to generate N unit time series (step S24), and obtains the sum of the unit time series to obtain an emphasized waveform with a length of one cycle of the AC power supply (step S25). Since partial discharges occur in accordance with the phase of the AC power, the peak phases of partial discharges in each of the N unit time series are approximately the same. Therefore, the emphasized waveform, which is the sum of the unit time series, is a waveform in which partial discharges are emphasized. The processor 171 is an example of a data generation unit that generates an emphasized waveform.

[0036] The processor 171 converts the emphasized waveform into a frequency spectrum by performing a fast Fourier transform (step S26). The processor 171 diagnoses the state of the target electric power device 200 based on a combination of the spectrum intensity for each frequency and the number of samples for one cycle of the AC power supply obtained in step S22 (step S27). In other words, the processor 171 is an example of a diagnostic device. The processor 171 obtains the state by using a trained model obtained by machine learning, for example.

[0037] Specifically, the processor 171 can use a trained model trained in the following procedure. As the machine learning model, for example, a neural network model can be used. A partial discharge signal is obtained in advance from an equipment in which a desired defect occurs in a noise-free environment through an experiment. An environmental noise signal at the installation location of the target electric power equipment 200 is also obtained in advance through an experiment. A learning data set is prepared in which a combination of the spectral intensity for each frequency of an emphasized waveform generated from a signal obtained by adding the partial discharge signal and the environmental noise signal and the number of samples for one cycle of an AC power supply is used as an input sample, and a one-hot vector indicating a defect type is used as an output sample. The one-hot vector is an N+1-dimensional vector indicating N defect states and one "no defect" state, in which only one element is 1 and the other elements are 0. Using the above learning data set, the parameters of the machine learning model are updated so that the value of the output sample is output when an input sample is input, thereby obtaining a trained model. The processor 171 inputs a combination of the spectral intensity for each frequency obtained from the emphasized waveform and the number of samples for one cycle of an AC power supply into the trained model, and outputs a state corresponding to the element with the largest value among the obtained vectors.

[0038] The results of calculations by the processor 171 are output to a display device and displayed.

[0039] As described above, according to the embodiment, the measuring device 110 generates a time series of discharge signal values ​​by sampling the measurement values ​​measured by the partial discharge sensor 111 at a first period, and transmits the time series of discharge signal values ​​to the diagnostic device 150. The diagnostic device 150 also calculates the period of AC power supplied to the target electric power device 200, and extracts a partial time series relating to a time that is an integer multiple of the period of the AC power from the time series of discharge signal values ​​based on the calculated period and the first period. In this way, the diagnostic system 100 according to the embodiment described above can detect a partial discharge signal corresponding to the period of the AC power.

[0040] In particular, according to the above-described embodiment, the diagnostic system 100 can detect a partial discharge signal without synchronizing the measuring device 110 and the diagnostic device 150. This eliminates the need to synchronize the clocks of the measuring device 110 and the diagnostic device 150, and the measuring device 110 and the diagnostic device 150 can be controlled as independent devices. In addition, since it is not necessary to obtain the period of the AC power in the measuring device 110, the measuring device 110 can be battery-powered and can be made compact. Note that the measuring device 110 according to other embodiments may be powered by the same AC power as the target electric power device 200. In addition, the measuring device 110 and the diagnostic device 150 according to other embodiments may be connected by wired communication.

[0041] Furthermore, according to the above-described embodiment, the measurement device 110 transmits a time series of discharge signal values ​​related to a time obtained by adding a margin in consideration of an error in the AC power cycle and an error in the clock circuit cycle to the rated cycle of the AC power. This makes it possible to supply the diagnosis device 150 with a time series of discharge signal values ​​of a sufficient data size regardless of fluctuations in the AC power cycle or the clock circuit cycle. Note that the measurement device 110 according to other embodiments may transmit a time series of discharge signal values ​​regardless of errors in the AC power cycle or the clock circuit cycle. For example, the measurement device 110 may transmit the measured discharge signal values ​​to the diagnosis device 150 one by one.

[0042] Moreover, the diagnostic device 150 according to the above embodiment divides a partial time series relating to a time N times the cycle of the AC power into N unit time series relating to one cycle, and generates an emphasized waveform by adding up the N unit time series. In this way, the diagnostic device 150 can obtain a waveform in which partial discharge is emphasized. Note that the diagnostic device 150 according to other embodiments may generate an emphasized waveform by calculating an average of N unit time series. Also, the diagnostic device 150 according to other embodiments may generate an emphasized waveform by calculating an average of N unit time series. It is not necessary to extract a partial time series relating to one cycle of the AC power and generate an emphasized waveform.

[0043] According to at least one of the embodiments described above, by having the measuring device 110 that generates a time series of discharge signal values ​​by sampling the measurement values ​​measured by the partial discharge sensor 111 at a first period and transmits the time series of discharge signal values ​​to the diagnostic device 150, and the diagnostic device 150 that calculates the period of AC power supplied to the target electric power device 200 and extracts a partial time series relating to a time that is an integer multiple of the period of the AC power from the time series of discharge signal values ​​based on the calculated period and the first period, it is possible to detect a partial discharge signal corresponding to the period of the AC power.

[0044] Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope of the invention and its equivalents described in the claims, as well as in the scope and spirit of the invention.

[0045] In other embodiments, computer 113 and computer 155 may include a custom LSI (Large Scale Integrated Circuit) such as a PLD (Programmable Logic Device) in addition to or instead of the configurations shown in Figures 2 and 3. Examples of PLDs include PAL (Programmable Array Logic), GAL (Generic Array Logic), CPLD (Complex Programmable Logic Device), and FPGA (Field Programmable Gate Array). In this case, some or all of the functions realized by processor 131 or processor 171 may be realized by the integrated circuit. Such an integrated circuit is also included in an example of a processor. [Explanation of symbols]

[0046] 100...diagnosis system 110...measuring device 111...partial discharge sensor 112...data generation circuit 113...computer 114...wireless communication device 121...amplifier circuit 122...filter circuit 123...AD conversion circuit 124...clock circuit 131...processor 132...main memory 133...storage 134...DMA controller 135...interface 150...diagnosis device 151...transformer 152...power supply circuit 153...sample number calculation circuit 154...wireless communication device 155...computer 161...AD conversion circuit 162...clock circuit 163...cross detection circuit 164...counter circuit 165...multiplication circuit 166...division circuit 171...processor 172...main memory 173...storage 174...DMA controller 175...interface 200...target power device 210...box 220…Device body

Claims

1. A measuring device attached to the power equipment and configured to measure a partial discharge signal; an extraction device that extracts a partial time series corresponding to a period of AC power supplied to the power device from a time series of measurement values ​​of the partial discharge signal measured by the measurement device; Equipped with The measuring device includes: A partial discharge sensor that measures a partial discharge signal emitted from an electric power device; a sampling unit that generates a time series of discharge signal values ​​by sampling a measurement value by the partial discharge sensor at a first period; a transmitter for transmitting a time series of the discharge signal value; Equipped with The extraction device comprises: a power input unit that receives AC power from a power source of the AC power supplied to the power device; A period calculation unit that calculates a period of the AC power; a receiving unit that receives a time series of the discharge signal value from the measurement device; an extracting unit that extracts a partial time series relating to a time that is an integer multiple of a period of the AC power from the time series of the discharge signal value based on the calculated period and the first period; Equipped Partial discharge signal detection system.

2. The extraction device comprises: a sampling unit that generates a time series of voltage values ​​by sampling a measurement value of a voltage related to the AC power at a second period; the period calculation unit measures a number of samples of the voltage value in one period of the voltage based on a time series of the sampled voltage values; The extraction unit obtains the number of samples of the discharge signal value by multiplying the number of samples of the voltage value by the second period and dividing the result by the first period, and extracts the partial time series of the number of samples of the discharge signal value from the time series of the discharge signal value. The partial discharge signal detection system of claim 1 .

3. The transmission unit transmits a time series of the discharge signal values ​​relating to a time obtained by adding a margin in consideration of an error in the period of the AC power to a rated period of the AC power. The partial discharge signal detection system according to claim 1 or 2.

4. The transmission unit transmits a time series of the discharge signal values ​​relating to a time obtained by adding a margin in consideration of an error between the first period and the second period to a rated period of the AC power. The partial discharge signal detection system of claim 2 .

5. The extraction device comprises: a data generating unit that divides a partial time series relating to a time that is an integer multiple of two or more of the period of the AC power into a plurality of unit time series relating to one period, and generates an emphasized waveform by adding up the plurality of unit time series; The partial discharge signal detection system according to claim 1 , further comprising:

6. A partial discharge signal detection system according to any one of claims 1 to 5; A diagnostic device for diagnosing the state of the power equipment based on the partial time series detected by the partial discharge signal detection system. A diagnostic system comprising:

7. A measuring device attached to an electric power equipment measures a partial discharge signal emitted from the electric power equipment; The measurement device generates a time series of discharge signal values ​​by sampling the measurement values ​​of the partial discharge signal at a first period; a measurement device transmitting a time series of the discharge signal values; An extraction device provided separately from the measurement device receives AC power from a power source of the AC power supplied to the power equipment; The extraction device calculates a period of the AC power; receiving, by the extraction device, a time series of the discharge signal values ​​from the measurement device; extracting, by the extraction device, a partial time series relating to a time that is an integer multiple of a period of the AC power from the time series of the discharge signal values ​​based on the calculated period and the first period; The partial discharge signal detection method includes:

8. a receiving unit that is attached to the power equipment and receives a time series of discharge signal values ​​sampled in a first period from a measuring device that measures a partial discharge signal; a power input unit that receives AC power from a power source of the AC power supplied to the power device; A period calculation unit that calculates a period of the AC power; an extracting unit that extracts a partial time series relating to a time that is an integer multiple of a period of the AC power from the time series of the discharge signal value based on the calculated period and the first period; A detection device comprising:

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