JP2019174425A - Computing system and method for evaluating power apparatus - Google Patents

Abstract

To provide a computing system which can accurately evaluate a power apparatus based on a measured discharge signal even when a discharge signal emitted from the power apparatus cannot be measured perfectly.SOLUTION: The computing system according to the present invention includes: an electronic circuit for measuring a high-frequency discharge signal output from a sensor; a controller for controlling the electronic circuit; and a memory for recording the high-frequency discharge signal measured by the electronic circuit. The controller controls the electronic circuit so that the timing of measuring the high-frequency discharge signal is adjusted according to an alternating cycle, acquires the high-frequency discharge signal measured by the electronic circuit by the memory, and reproduces the high-frequency discharge signal generated in the power apparatus on the basis of the high-frequency discharge signal.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a computer system for evaluating a power device, and more particularly to a computer system for measuring a discharge signal generated in a power cable and diagnosing an insulation failure of the power cable, and a method thereof.

  Diagnosing a power device is important in order to stably operate a power system and a power system in a predetermined area such as a factory or a building. On the other hand, due to the fact that the lifespan of power equipment is long, the environment in which each power equipment is used is different, and the mechanism by which power equipment deteriorates, there are various factors. It is not easy to diagnose any abnormalities. Therefore, a system that supports diagnosis of electric power equipment has been proposed.

  For example, Patent Document 1 discloses an on-site monitoring device for detecting the intensity of a detection signal of a partial discharge sensor for the purpose of obtaining a partial discharge remote monitoring device that can efficiently measure even intermittent discharge and can monitor at low cost for 24 hours. Compared with the reference intensity of the comparison circuit 18, when the intensity of the detection signal is equal to or higher than the reference intensity, a system is described that transmits a detection signal that exceeds the reference intensity to the monitoring terminal via the communication means. .

  Furthermore, Patent Document 2 discloses that a signal output from a partial discharge sensor is signal-processed for the purpose of providing a power cable abnormality diagnosis device that automatically detects the occurrence of an abnormality in a power cable connection after installation. After being processed by the unit, it is given to the buffer memory. The data processing unit detects an abnormality in the insulation of the cable by increasing the peak value of the partial discharge pulse near the zero cross of the applied voltage in the φ-q distribution (or φ-qn distribution) of the partial discharge. Are listed.

JP 2007-232495 A JP-A-5-80112

  Even if the system of the above-mentioned conventional example tries to diagnose the insulation performance of the power cable based on the discharge signal generated in the gap portion (oil gap, gap, etc.) inside the insulator of the power cable, the operating frequency of the measurement circuit is high. In the first place, it is difficult to accurately determine whether the insulation performance of the power cable is good or not from the measurement result of the partial discharge signal, no matter how good the program for diagnosis is unless it can cope with the signal. Therefore, the present invention provides a computer system and method for accurately evaluating a power device based on the measured discharge signal even when the discharge signal emitted from the power device cannot be completely measured. It is the purpose.

  In order to achieve the above object, the present invention provides a computer system for measuring a high frequency discharge signal from a power device to which AC power is applied, and evaluating the power device based on the high frequency discharge signal. An electronic circuit that measures the high-frequency discharge signal output from the controller, a controller that controls the electronic circuit, and a memory that records the high-frequency discharge signal measured by the electronic circuit, the controller comprising the high-frequency discharge signal The electronic circuit is controlled so as to adjust the timing for measuring the high-frequency discharge signal measured by the electronic circuit from the memory, and based on the high-frequency discharge signal, the power device is controlled. This is a computer system that reproduces the generated high-frequency discharge signal. The present invention is further a method for evaluating a power device.

  According to the present invention, it is possible to provide a computer system that can accurately evaluate a power device based on the measured discharge signal and a method thereof even when the discharge signal emitted from the power device cannot be completely measured. it can.

It is a block diagram of the hardware concerning the example of the form which applied the computer system to the power cable. It is a block diagram which shows the structural example of the hardware of a computer system. It is a wave form diagram which shows the partial discharge signal which generate | occur | produces in the insulation defect location of a power cable, and is detected by the sensor synchronizing with commercial AC power (for 1 phase). It is a wave form diagram which shows an example of the measurement operation | movement of a computer system. It is a functional block diagram of the computer system of FIG. It is a flowchart which shows an example of operation | movement of a computer system. It is a flowchart which concerns on an example of the process in which a computer system diagnoses a power cable. It is a flowchart explaining an example of the signal measurement operation | movement of a computer system.

  Hereinafter, embodiments of a computer system according to the present invention will be described with reference to the drawings. This computer system is for evaluating power equipment, and the evaluation includes diagnosing the quality of the insulation performance of the power equipment. As power equipment, a power system (power transmission network, power distribution network), a power transmission network to a large-scale consumer such as a factory, a building, a commercial facility, or a station, and a power cable used for the power distribution network will be described as preferable examples. . The computer system measures the high frequency signal emitted from the power cable and diagnoses the quality of the insulation performance of the power cable. The high-frequency signal may be a discharge signal generated in a gap portion (oil gap, gap, etc.) inside the insulator of the power cable. Hereinafter, this signal is referred to as a partial discharge signal.

  FIG. 1 is a block diagram of hardware according to an example in which a computer system is applied to a power cable. Reference numeral 100 denotes a power cable. The power cable 100 may be an oil-filled paper cable (Oil Filled: OF) or a CV cable (Crosslinked polyethylene: CV).

  Reference numeral 101 denotes a sensor for detecting a partial discharge signal. In order to detect partial discharge signals from the power cable, a plurality of sensors exist at predetermined intervals along the power cable, such as 101a and 101b. The sensor may be a high frequency CT (Current Transformer). The sampling frequency of the high frequency CT is several hundred MHz or more, and even a partial discharge signal can be sufficiently detected.

  A computer system 102 exists for each of a plurality of sensors. Reference numeral 102a denotes a computer system connected to the sensor 101a, and reference numeral 102b denotes a computer system connected to the sensor 101b. The computer system diagnoses the power cable based on the high frequency signal (partial discharge signal) output from the sensor.

  The computer system 102 may be a personal computer, a field device in edge computing, a gateway in fog computing, a controller, a PLC (Programmable Logic Controller), an IED (Intelligent Electronic device), or an MU (Merging Unit). The computer system may be applied to a protection relay.

  Reference numeral 103 denotes a signal transmission cable output from the sensor 101 to the diagnostic apparatus 102. Since the transmission target is a high-frequency signal, a coaxial cable is generally sufficient. Reference numeral 104 denotes a storage. The storage stores a partial discharge signal measured by the computer system 102, a result of diagnosis of the power cable, information related to the power cable 100, and the like. The information related to the power cable includes the material of the power cable 100, the dimensions of each part, the parameters and weights of the electrical characteristics, the cable length, the date of manufacture, the date of installation, etc. Various information for operating the power cable, such as the energized voltage, the tidal flow, the past operation results, the power failure history, the connection configuration on the power system, and the connection relationship with other systems, may be used.

  Reference numeral 105 denotes a server. The server 105 performs integrated management of the plurality of computer systems 102 and refers to information recorded in the storage 104 to determine the power cable comprehensively. For example, the server uses the diagnostic information of the plurality of computer systems 102 to determine the position of the oil gap and / or the like and / or predicts the period until the insulation breakdown of the power cable 100. The server may share information with the central power supply command station, the control station, the power supply station, the substation, and the like for comprehensive determination. A plurality of servers 105 may exist for reasons such as differences in processing contents and distribution of processing loads. The same applies to the storage 104.

  The network 106 is connected to the computer system 102, the storage 104, and the server 105, and transmits information between them. Examples of implementations of the network 106 include IEEE 802.3, various industrial networks, IEC 61784, IEC 61158, IEC 61850 (including IEC 61850-90-3), IEC 62439, IEC 61850-7-420, IEC 60870-5 104, DNP (Distributed Network Protocol) 3, IEC 61970, IEEE 802.1 AVB, CAN (Controller Area Network: registered trademark), DeviceNet, RS-232C, RS-422, RS-485, ZoB, ZB (Registered trademark), IEEE 802.15, IEEE 802.1, mobile communication, OpenADR, ECHONET Lite (registered trademark), OpenFlow (registered trademark) or the like may be used. The communication format between the computer system 102, the storage 104, and the server 105 follows the above protocol.

  The communication protocol of the application layer may be web, HTTP (Hypertext Transfer Protocol), XML (Extensible Markup Language), SOAP, RPC (Remote Procedure Call), or SQL.

  The computer system 102 may exist without being connected to the network 106. In that case, the computer system 102 may have a storage function inside. Examples of the storage function of the storage 104 and the computer system 102 include a database, a file server, a storage device, a NAS (Network Attached Storage), a SAN (Storage Area Network), or a nonvolatile storage medium or an external storage medium. Good.

  The nonvolatile storage medium may be a hard disk drive (HDD), a solid state drive (SSD), or a flash memory. As an easily removable external storage medium, a floppy disk (FD), CD, DVD, Blu-ray (registered trademark), USB memory, compact flash (registered trademark), or the like may be used. For these storage media, the computer system 102 may be provided with a dedicated connection interface.

  Next, an example of the hardware configuration of the computer system 102 is shown in FIG. The CPU 120 transfers the program from the nonvolatile storage medium 125 to the memory 124 and executes the program. Examples of the execution program include an operating system (hereinafter referred to as OS) and an application program that runs on the OS. The CPU 120 may be a multi-core CPU, a many-core CPU, or an FPGA built-in CPU.

  The LAN 121 receives a transmission request and transmission data from software operating on the CPU 120, transmits the data to the network 106, and transmits the data received from the network 106 to the CPU 120, the memory 124, and the nonvolatile memory via the bus 126. To the volatile storage medium 125. An implementation example of the LAN 121 may be an IC such as an FPGA, CPLD, ASIC, or gate array, or may be integrated with the CPU 120. The LAN 121 may be an IEEE 802.3 communication device including a MAC layer and a PHY (physical) layer, or may include a PHY function. The LAN 121 may be an IEEE 802.3 standard MAC (Media Access Control) chip, a PHY chip, or a combined MAC and PHY chip. The LAN 121 may be included in the CPU 120 or a chip set that controls an information path inside the computer.

  The data processing IC 122 measures the sensor data transferred from the ADC 123 and transmits the processing result to one or more of the CPU 120, the memory 124, the nonvolatile storage medium 125, and the LAN 121 via the bus 126. Information may be set in the data processing IC 122 by access from the CPU 120, the LAN 121, and the like. Information to be set includes circuit configuration information as an IC (FPGA, CPLD, etc.) and parameters related to sensor data measurement.

  Implementation examples of the data processing IC 122 are FPGA, CPLD, general-purpose IC, dedicated ASIC, gate array, FPGA incorporating a processor, and software operating on them. Circuit configuration information (configuration data) when the FPGA and CPLD are mounted may be stored in the nonvolatile storage medium 125 and read as necessary. The nonvolatile storage medium 125 that stores circuit configuration information may be directly connected to the data processing IC 122 as a dedicated nonvolatile storage medium without being connected to the bus 126.

  The ADC 123 is an analog to digital converter that converts an analog signal transmitted from the sensor 101 into a digital signal and transmits the analog signal to the data processing IC 122. Note that a plurality of ADCs 123 may be provided, and the partial discharge signals may be measured by shifting the respective capture phases. In this way, a high-frequency partial discharge signal can be measured even if the sampling frequency of the ADC 123 alone is low resolution.

  The memory 124 is a storage area for storing programs and temporarily storing data, and stores an OS, application programs, and the like transferred from the nonvolatile storage medium 125. Examples of the memory 124 include static RAM, DRAM, and NVRAM.

  The non-volatile storage medium 125 is an information storage medium, and is used to store an OS, an application, a device driver, etc., a program for operating the CPU 120, and data that is the execution result of the program. Examples of the nonvolatile storage medium 125 include a hard disk drive (HDD), a solid state drive (SSD), and a flash memory. Examples of the external storage medium that can be easily removed include use of a floppy disk (FD), CD, DVD, Blu-ray (registered trademark), USB memory, compact flash (registered trademark), and the like.

  The bus 126 connects the CPU 120, the LAN 121, the memory 124, and the nonvolatile storage medium 125, respectively. Examples of the bus 126 include a PCI bus, an ISA bus, a PCI Express bus, an AMBA (registered trademark) bus, a system bus, a memory bus, an on-chip bus, and the like.

  If the sampling frequency of the data processing IC 122 and the ADC 123 is 200 MHz and the frequency of the partial discharge signal output from the sensor 101 is 500 MH, the computer system 102 cannot sufficiently measure the partial discharge signal. The degree of defect cannot be diagnosed correctly. However, in the computer system 102, even if the data processing IC 122 has a low cost and the sampling frequency is inferior to the frequency of the partial discharge signal output from the sensor 101, the partial discharge generated in the power cable based on the measurement data. The signal is reproduced so that the degree of deterioration of the insulation performance of the power cable can be accurately diagnosed. “Reproduction” may be rephrased as “estimation”. The computer system 102 may be understood as including the server 105 and / or the storage 104. A plurality of computer systems may be collectively understood as one computer system.

  FIG. 3A is a waveform diagram showing a partial discharge signal that is generated at a location of poor insulation of power cable 100 and detected by sensor 101 in synchronization with commercial AC power (for one phase). Reference numeral 1000 in FIG. 3A indicates AC power, and for example, partial discharge signals a, b, c,... I is output in order every 2 ns. The sensor 101 detects and outputs the partial discharge signals a, b, c,... I in each of a plurality of cycles (first cycle, second cycle, third cycle,...).

  On the other hand, if the sampling frequency of the data processing IC 122 is 5 ns, the data processing IC 122 can measure only a part of the partial discharge signal per cycle of AC power. However, the computer system 102 superimposes a plurality of AC cycles, synthesizes the partial discharge signals measured by the data processing IC 122 while shifting the measurement start phase in each of the plurality of cycles, and is actually generated by the power cable. The pattern of the high-frequency partial discharge signal was reproduced in at least one cycle, and this was evaluated so that the insulation state of the power cable could be accurately diagnosed. The computer system 102 may determine the AC cycle based on the applied voltage cycle (commercial AC power) of the power cable. Preferably, the cycle may be the same as the applied voltage cycle. A plurality of AC cycles are the minimum observation period, and one cycle belonging to the observation period is a unit period.

  As shown in FIG. 3B, the CPU 120 determines the number of cycles to be superimposed as “3” based on the sampling frequency: 200 MHz of the data processing IC 122 and the frequency of the partial discharge signal: 500 MHz, and sends this to the data processing IC 122. Set. Further, the CPU 120 determines the shift amount of the measurement start phase as 1 ns, and sets this in the data processing IC 122.

  As the measurement cycle, the number of cycles to be superimposed may be determined by the frequency of the partial discharge signal and the operating frequency on the diagnostic device side (such as the operating frequency of each of the ADC 123 and the data processing IC 122). The data processing IC (FPGA) 122 can adjust the shift amount of the signal capture phase in units of ns.

  The data processing IC 122 measures a partial discharge signal every 5 ns, which is its operating frequency, and the data processing IC 122 further shifts the measurement start phase by 1 ns from the starting point 1002 of the first cycle and outputs the partial discharge. When the signal measurement is started, the partial discharge signals a, d, f, and i can be measured in the first cycle.

  When the data processing IC 122 continues the measurement of the partial discharge signal output from the sensor by shifting the measurement start phase by 1 ns from the starting point 1004 of the second cycle and further shifting by 2 ns in total, in the second cycle, the partial discharge signal b , E, g, j can be measured. Furthermore, when the data processing IC 122 continues to measure the partial discharge signal output from the sensor by shifting the measurement start phase by 1 ns from the starting point 1006 of the third cycle and further shifting the total phase by 3 ns, in the third cycle, the partial discharge signal c , H can be measured.

  The CPU 120 synthesizes the partial discharge signals measured in each cycle from the first cycle to the third cycle in consideration of the phase difference of the partial discharge signals from the start point of the cycle. The generated partial discharge signals a, b,..., I, j can be reproduced.

  Next, a functional block diagram (FIG. 4) of the computer system 102 will be described. The “module” shown in FIG. 4 is realized by one or more elements shown in FIG. A module may be understood as a function implemented by a program and / or hardware. The module may be rephrased as “means”, “part”, or “element”.

  The phase setting module 110 refers to the information in the storage area 115 to obtain the above-described phase shift amount (“1 ns” in FIG. 3B), and sets this in the measurement signal receiving module 113. Based on the AC cycle of the voltage applied to the power cable 100, the phase setting module 110 sets the AC signal start module, AC cycle time information, AC cycle zero-cross timing, and the like in the measurement signal receiving module 113.

  The cycle number setting module 116 refers to the information in the storage area 115, determines the number of cycles to be superimposed as described above, and sets this in the measurement signal receiving module 113. Note that the storage area 115 may be configured in the nonvolatile storage medium 125 and / or the storage 104. Furthermore, the phase setting module 110 may determine the phase shift amount based on control information from the outside by connecting to the communication module 114. The cycle number setting module 116 may also determine the number of cycles to be superimposed based on control information from the outside by connecting to the communication module 114.

  The measurement signal receiving module 113 measures the partial discharge signal output from the sensor 101 based on the set information. The measurement signal receiving module 113 includes a CPU, a microcomputer, a CPU, a specific hardware function module in the microcomputer, an FPGA (Field Programmable Gate Array), a CPLD (Complex Programmable Logic Device), a dedicated IC, and analog / digital conversion. Implemented by one or more of the circuits. Note that the measurement signal receiving module 113 may take in the measurement value after confirming that the measurement signal is correctly measured. This is because there is a possibility of a soft error in the FPGA used by the data processing IC 122 or an abnormality in the sensor 101 or the ADC 123.

  The measurement signal receiving module 113 stores the measured signal in the storage area 115. The measurement signal reception module 113 may store the partial discharge signal in the storage area 115 after determining whether or not the captured partial discharge signal should be stored in the storage area 115, or may perform a predetermined calculation on the measured partial discharge signal. The added result may be stored in the storage area 115.

  The diagnosis module 112 refers to the storage area 115, determines an abnormality of the power cable 100 that is the diagnosis target based on the partial discharge signal captured by the measurement signal reception module 113, and stores the determination result in the storage area 115. .

  The communication module 114 receives a command / setting packet to the computer system 102 via the network 106 and transmits a packet from the computer system 102 to the storage 104 or the server 105. The communication module 114 performs communication by shaping a signal in accordance with the protocol format of the network 106.

  Since the communication module 114 causes the other computer system 102, the storage 104, and the server 105 to execute predetermined processing within a certain delay (for example, measurement data storage processing to the other computer system 102), the maximum communication delay is guaranteed. A real-time communication method may be provided.

  The storage area 115 stores related information necessary for determining the phase shift amount in the phase setting module 110 and determining the number of cycles to be superimposed in the cycle number setting module 116. Related information includes the material of the power cable 100, the dimensions of each part of the power cable 100, the parameters and weight of the electrical characteristics of the power cable 100, the cable length of the power cable 100, the date of manufacture of the power cable 100, and the power Attribute information of the power cable 100 such as date of laying of the cable 100, energized voltage, tidal flow, past operation results, oil pressure history of oil-impregnated paper cable, power outage history, connection configuration on the power system, and other systems Operational information of the power cable 100 such as connection relations, actual measured values (charge amount, phase) of partial discharge signals, historical information of partial discharge signals such as past measured values of partial discharge signals, attribute division of the computer system 102 (data Processing IC 122, ADC operating frequency, etc.) and one or more of the measurement attributes such as the number of cycles to be superimposed as described above. The CPU 120 may determine the phase shift amount based on the operating frequency of the data processing IC 122 and the number of cycles to be superimposed. The CPU 120 may predict the frequency of the partial discharge signal and the charge amount from the attribute information and operation information of the power cable. CPU 120 may determine the number of cycles to be superimposed based on the frequency of the partial discharge signal and the operating frequency of data processing IC 122.

  The time synchronization module 118 synchronizes the computer system 102 with one or more of the other computer systems 102, the storage 104, and the server 105 in accordance with a predetermined time synchronization protocol. The time synchronization module 118 implements GPS, NTP, IEEE 1588, IRIG-B, etc. as a method for synchronization. The time system to be synchronized may be a relative time when the system of FIG. 1 is closed and operated, or may be an absolute time when linked with an external system.

  Each of the plurality of computer systems 102 is provided with a time synchronization module 118 so as to be synchronized with each other. Signals measured by each of the plurality of computer systems 102 are given time information at the time of measurement and stored in the storage 104.

  The server 105 further manages information on which part of the power cable each of the plurality of computer systems is targeted, and refers to the determination result of each of the plurality of computer systems to determine which of the power cables at the same time. It is possible to specify whether or not a partial discharge has occurred at a location.

  Next, an example of the operation of the computer system 102 will be described based on the flowchart of FIG. The computer system 102 executes the flowchart of FIG. 5 every predetermined time (for example, every 10 minutes). Hereinafter, the flowchart of FIG. 5 will be described with reference to the block diagrams of FIGS.

  The CPU 120 waits for the start of partial discharge signal measurement (S001). During this time, the phase setting module 110 detects the starting point of the AC cycle, sets this as the measurement signal receiving module 113 as the measurement start point of the partial discharge signal, and the cycle number setting module 116 further superimposes the cycle. The number (3 cycles in FIG. 3B) is set in the measurement signal receiving module 113. For the sake of convenience, a period of a plurality of superimposed cycles will be abbreviated as “measurement cycle” hereinafter. Further, the phase setting module 110 determines the phase amount to be shifted (“1 ns” in FIG. 3B). The cycle setting module 116 records the number of measurement cycles, and the phase setting module 110 records the phase amount to be shifted in the storage area 115.

  When the CPU 120 finishes the standby process (S001), the CPU 120 proceeds to S002 and causes the measurement reception signal reception module 113 to perform measurement of the partial discharge signal. When the measurement signal receiving module 113 detects the partial discharge signal, the measurement signal receiving module 113 acquires the discharge charge amount of the partial discharge signal and the phase from the cycle start point (1002, 1004, 1006 in FIG. 3B) until the partial discharge signal is measured, This is accumulated and stored in the storage area 115.

  When the measurement of the partial discharge signal is started, the measurement signal receiving module 113 sets a predetermined time in the timer, and when the predetermined time has elapsed (S003), the measurement ends. The predetermined time may be a sufficient time necessary for the diagnostic module 112 to obtain measurement data necessary for reproducing the partial discharge signal. For example, when 10 cycles of one cycle of commercial power 50 Hz (20 milliseconds) are evaluated, the time is 200 milliseconds.

  Next, processing in which the computer system 102 diagnoses the power cable 100 will be described. FIG. 6 is a flowchart thereof. The CPU 120 starts this flowchart at predetermined time intervals (for example, every hour) and activates the diagnosis module 112. The diagnosis module 112 refers to the storage area 115 and determines the presence or absence of an unevaluated measurement signal (partial discharge signal) (S100). When the diagnosis module 112 denies this determination, that is, determines that there is no unevaluated measurement signal in the storage area 115, the flowchart ends. When the partial discharge is not generated in the power cable, or when the measurement signal is equal to or less than the predetermined value, the measurement signal is not recorded in the storage area 115, so the diagnosis module 112 makes a negative determination in S100.

  When the diagnostic module 112 determines that there is an unevaluated measurement signal (S100: Y), the partial discharge signal in the power cable is reproduced based on the charge amount and phase of the measurement signal (S102: see FIG. 3B). . The diagnostic module 112 preferably removes noise from the detected signal when reproducing the partial discharge. Examples of noise removal include a method using a signal processing technique such as a low-pass filter, a high-pass filter, a band-pass filter, a Fourier transform, and a wavelet transform.

  Next, the diagnostic module 112 calculates an index value for diagnosing the quality of the insulation performance of the power cable from the characteristics of the reproduced partial discharge signal (S104). This index value includes, for example, the maximum discharge charge amount of the measurement value of the partial discharge signal, the initial expression phase of the measurement signal, the frequency of the measurement signal, the total value of the discharge charge amounts of the plurality of measurement signals, and the phase of the plurality of measurement signals One or more of the minimum value, the maximum value, the average value, the standard deviation, the change rate of the discharge charge amount of a plurality of measurement signals, and the maximum amplitude when the measurement signals are converted into a frequency spectrum may be used. .

  Next, the diagnosis module 112 compares the evaluation value with a threshold value (S106). The diagnostic module 112 determines that there is an abnormality in the power cable when the evaluation value has a specific relationship with the threshold value (S108). The specific relationship is, for example, when the evaluation value is larger than the threshold value, when the evaluation value is equal to the threshold value, when the evaluation value is smaller than the threshold value, when the evaluation value includes the threshold value, or The evaluation value may not include a threshold value. The relationship between the evaluation value and the threshold value may depend on the determination method.

  The diagnostic module 112 determines whether the partial discharge start phase is earlier than the predetermined phase, the minimum charge amount of the partial discharge signal is lower than a predetermined threshold value, or the minimum value of the occurrence phase of the partial discharge signal occurrence phase. May be determined to be abnormal when the power cable is lower than a predetermined threshold. Furthermore, the diagnostic module 112 may determine that there is an abnormality in the power cable when the state where the partial discharge signal is intermittently generated changes to the state where the partial discharge signal is continuously generated. Good. The diagnosis module 112 may evaluate the power cable by obtaining the degree of change of the index value based on the index value history and comparing it with a predetermined threshold value.

  The evaluation module 112 may combine a plurality of determination methods when evaluating the power cable. In this case, the diagnosis module 112 may compare a value obtained by adding the parameters (for example, the difference between the index value and the threshold value) of each of the plurality of determination methods as a sum of the values with the threshold value as an integrated parameter. Alternatively, the diagnosis module may finally determine the abnormality of the power cable only when the power cable is determined to be abnormal in a predetermined number of determination methods among the plurality of determination methods. The diagnostic module may execute a plurality of determination methods in parallel, or may execute a plurality of determination methods in order. The diagnosis module may execute a plurality of determination methods in a hierarchical manner. For example, the diagnosis module first performs a determination regarding the maximum value of the partial discharge charge amount. If the determination module determines that this method is abnormal, then an abnormality determination relating to the minimum value of the partial discharge charge amount is applied. When the diagnosis module does not determine that the maximum charge amount is abnormal, the diagnosis module executes a determination method for the amplitude of the frequency spectrum. As described above, the diagnosis module can sequentially improve the accuracy for diagnosis by executing the determination method hierarchically.

  The diagnostic module not only reproduces the partial discharge of the power cable based on a plurality of consecutive cycles, but also reproduces the partial discharge by combining cycles existing in multiple measurement cycles. Good.

  When the diagnosis module 112 determines that the power cable is abnormal, the diagnosis module 112 notifies the outside of the power cable and ends the flowchart. The notification may be made by notifying the storage 104 and the server 105 that there is an abnormality via the network 106, or the diagnostic apparatus 102 turns on an LED or the like and outputs an alarm such as a warning sound. If the diagnosis module 112 determines in S106 that there is no specific relationship, the flowchart ends.

  Next, the signal measurement operation (FIG. 5: S002) of the measurement signal receiving module 113 will be described according to the flowchart (FIG. 7) based on the measurement example shown in FIG. 3B. The CPU 120 causes the measurement signal receiving module 113 to start a signal measurement operation based on the measurement cycle and the phase shift amount. When the measurement signal receiving module 113 determines the starting point 1002 of the AC cycle 1000 (S200), it shifts the signal acquisition start phase by 1 ns (S202). Thereby, during the first cycle, the measurement signal receiving module 113 measures the partial discharge signals a, d, f, and i in order every 5 ns. The measurement signal receiving module 113 stores the measured charge amount and phase of the partial discharge signal in the storage area 115 (S204).

  Next, the measurement signal receiving module 113 returns to S200 when the next cycle is included in the measurement cycle (S206: Y), and when the next cycle is not included in the measurement cycle (S206: N). ) Shifts to S003 (FIG. 5).

  According to FIG. 3B, when the measurement diagnosis module 112 makes an affirmative determination in S206, returns to S200, and determines the cycle start point 1004, it shifts the signal acquisition start phase by 2 ns. As a result, the measurement signal receiving module 113 can measure the partial discharge signals every 5 ns during the cycle, and thus can measure the partial discharge signals b, e, g, and j. The measurement signal receiving module 113 stores the measured charge amount and phase of the partial discharge signal in the storage area 115.

  Next, when the measurement diagnosis module 112 makes an affirmative determination in S206 and returns to S200, and determines the cycle start point 1004, the signal acquisition start phase is shifted by 3 ns. Accordingly, the measurement signal receiving module 113 can measure the partial discharge signal every 5 ns during the cycle, and thus can measure the partial discharge signals of c and h. The measurement signal receiving module 113 stores the measured charge amount and phase of the partial discharge signal in the storage area 115.

  Subsequently, since the number of measurement cycles is “3” and there is no next cycle, the measurement diagnosis module 112 makes a negative determination in S206 and returns to S003 (FIG. 5).

The cycle number C of the AC cycle constituting the measurement cycle is assumed that the sampling frequency of the data processing IC 122 is “FIC” and the frequency of the partial discharge signal is “FPDM”.
As long as it satisfies the above.

The phase amount “Tshift” shifted for each cycle is expressed by the following equation.
“IIC” is one sampling time in the data processing IC 122 (1 s / 200 MHz = 5 ns). When the cycle number “C” is 3, “Tshift” is 1.67. However, since the amount of phase that can be shifted depends on the minimum adjustable unit time (for example, “1 ns”) in the data processing IC 122, the amount of phase that is actually shifted may be “1 ns” or “2 ns”. That's fine. Since the amount of phase that can be shifted is limited by the minimum adjustable unit time, the larger the cycle number “C”, the better. When the number of cycles increases, the measurement signal receiving module 113 can take in a larger amount of partial discharge signals, so that the resolution when reproducing a partial discharge signal of one cycle can be improved.

  The upper limit of the number of cycles may be determined according to, for example, the shape of the insulator and / or the period during which the output of the partial discharge signal can be considered constant. Based on the resolution of the ADC 123, it can be assumed that the partial discharge state of the power cable 100 (the generation mode of a plurality of partial discharge signals) does not change during “100 ms”, because one cycle is “20 ms”. “5” cycles (100 ms / 20 ms) is the upper limit of the number of cycles. The cycle number setting module 116 may determine the cycle number of the measurement cycle between the upper limit cycle number and the cycle number determined by Equation 1, or may vary the cycle number.

  Demonstrate a period in which an AC voltage is imitated on the power cable having the same material, length, and structure as the power cable 100 to be measured, and the partial discharge can be considered unchanged. Thus, a period in which the generation modes of the plurality of partial discharge signals are not changed may be obtained. Alternatively, the evaluation value for each cycle may be compared, and a period in which there is no change compared with a predetermined threshold may be a period in which the partial discharge state does not change. The measurement signal receiving module 113 may change the number of cycles based on a request from the server 105 and / or the system administrator via the network 106.

  When the number of cycles constituting the measurement cycle increases, the diagnostic module 112 can increase the resolution when reproducing the partial discharge signal generated in the power cable from the partial discharge signal measured during the measurement cycle. Although the accuracy of the determination can be improved, the probability that the partial discharge signal fluctuates during a large number of cycles is increased, and this is influenced by the reciprocity that reduces the accuracy of reproduction. Therefore, as described above, the number of cycles may be limited below the upper limit of the number of cycles so that the reproduction accuracy does not decrease even within a range where the partial discharge signal does not vary.

  In the above description, it has been described that the phase setting module 110 shifts the measurement start phase every cycle of the AC cycle. However, the measurement start phase may be shifted every plural cycles. In the above description, the diagnostic module 112 reproduces the partial discharge of the power cable based on the partial discharge signal measured in a plurality of consecutive cycles. However, the diagnostic module 112 reproduces the partial discharge by combining several non-consecutive cycles. Also good. For example, the diagnostic module 112 may reproduce the partial discharge signal by combining the measurement signals of several cycles, excluding the cycle to which an inappropriate signal such as a noise signal or an outlier is added.

  The diagnostic module 112 may determine noise signals and outliers using statistical techniques such as clustering classification. The diagnostic module 112 may obtain a frequency spectrum and remove a high frequency band or harmonic signal from the measurement signal. The diagnosis module 112 may perform this removal based on the calculation results (statistical method and frequency spectrum) for other cycles. For example, when a signal in a specific frequency band is measured in a certain cycle, the diagnosis module 112 may remove this by using a filter in another cycle by filtering, removing it by inverse Fourier transform, and the like. In addition, the diagnostic module 112 may filter the measurement signal in this frequency band when the frequency of a noise signal such as a harmonic can be determined or estimated from the physical characteristics of the measurement result.

  In the above description, it has been described that the phase setting module 110 shifts the phase regardless of the characteristics of the measured partial discharge signal. However, when the change degree of the partial discharge exceeds a predetermined threshold value. For example, the phase may be shifted.

  In the above description, it has been explained that the phase setting module 110 sets the phase shift amount to a constant value, but the shift amount is set according to a change in the characteristics of the partial discharge signal, a change in the noise generation period, or the like. It may be changed. The phase setting module 110 may randomly change the phase shift amount according to the cycle. The phase setting module 110 may limit the phase shift amount that is randomly changed to the lower limit value and / or the upper limit value. The phase setting module 110 may evaluate the phase shift amount set at random after measuring the partial discharge signal, and determine the phase shift amount based on the evaluation. This evaluation may be based on the number of phase shift amounts set at random, the number of times that the power cable is diagnosed as abnormal, the frequency, the number of times that measurement data needs to be stored, the frequency, and the like. When the phase setting module 110 determines by evaluation that the phase shift amount is not appropriate, the phase shift module may set the phase shift amount again at random.

  When the computer system 102 starts measuring the partial discharge signal, the phase setting module 116 sets the phase shift amount to be smaller than the value of Equation 2, and the cycle number setting module 116 sets the cycle number to be larger than the value of Equation 1. The resolution of sampling for measuring the partial discharge signal is increased so that the measurement of the partial discharge signal is not missed when the measurement is started. After that, when the measurement signal receiving module 113 does not measure the partial discharge signal, the computer system 102 may increase the phase shift amount and decrease the number of measurement cycles to reduce the sampling resolution after starting the measurement. Good. In this way, the computer system may change the phase shift amount and the number of measurement cycles in accordance with the progress of measurement of the partial discharge signal. Furthermore, the computer system 102 may dynamically determine the phase shift amount, for example, change, adjust, control, or set the phase shift amount based on the characteristics of the reproduced partial discharge signal. .

  The measurement signal receiving module 113 evaluates the measured partial discharge signal, for example, evaluates whether or not the charge amount of the partial discharge signal is equal to or greater than a predetermined value and whether there is an influence of noise. May be stored in the storage area 115. The measurement signal receiving module 113 may determine whether to store the measured signal based on the storable capacity or the storable throughput.

  The server 105 can devise a predetermined countermeasure based on the abnormality of the power cable 100 determined by the computer system 102. For example, the server 105 operates the system so that no power flows to the power cable determined to be abnormal, estimates a period until insulation breakdown, plans a periodic inspection within the period, and / or For example, replacement or maintenance is recommended.

  The server 105 can determine the period until dielectric breakdown based on the result of the verification test performed in advance, or may estimate the period based on past history information. The server 105 can also apply machine learning and statistical methods to this estimation. In the demonstration evaluation, the power cable may be charged until the dielectric breakdown occurs, or the power is stopped before the breakdown occurs, and the state inside the disassembled power cable is visually observed or applied with image processing. The presence or absence may be confirmed.

  The server 105 may evaluate the position of the oil gap based on the characteristics of the discharge charge amount measured by the single computer system 102. The server 105 can predict the position of the oil gap by machine learning with respect to the performance data, or evaluate the position of the oil gap by estimating the attenuation amount due to the absolute value of the discharge charge amount and the resistance component of the power cable. You can also The server 105 may present a proposal for a newly installed location or a changed location of the computer system based on the diagnosis result of one or a plurality of computer systems 102. For example, when two computer systems 102 measure a partial discharge signal, but the server 105 cannot accurately estimate the position of the oil gap because the discharge charge amount is weak, a new one is placed between the two computer system positions. A request to configure the computer system 102 may be presented. You may make it transfer the computer system which has not measured the partial discharge to this shown position.

  The server 105 outputs measurement data to the computer system 102 and / or the storage 104 based on the operation information of the power cable from the power supply facility such as the central power supply command station, the control station, and the substation. You may request it. For example, the server 105 causes a change in power flow (an increase or decrease in power flow, a reverse power flow) in the power cable 100 or a comparison with a predetermined threshold (such as an increase in power flow that exceeds a predetermined threshold). It may be instructed to output measurement data for a predetermined period before and after the set time.

  Further, the server 105 may instruct to output measurement data for a predetermined period before and after the abnormality or change of the hydraulic system of the OF cable or the date and time when the gas analysis in oil is performed. Furthermore, the server 105 may instruct to output measurement data for a predetermined period before and after an opening / closing operation to the circuit breaker or disconnector. Since switching surges due to switching operations can trigger partial discharge, it is important to observe measurement data associated with switching operations.

  Furthermore, the server 105 may output measurement data based on the occurrence time of a weather event such as a lightning strike. For example, when a lightning strike occurs near the power cable to be observed, the server may acquire a lightning strike time and instruct to output measurement data for a predetermined period before and after that time. Based on the computer system 102 and / or the storage 104, the server 105 can execute power cable diagnosis of the power cable in the same manner as the computer system 102. Instead of causing the computer system 102 and / or the storage 104 to output the target data, the server 105 may cause the computer system 102 to execute a diagnosis based on the target data and obtain the result.

  The server 105 analyzes power network information, machine learning, and the like based on the result of power cable diagnosis performed by the computer system 102, estimates a period until the insulation breakdown of the power cable, and determines the power cable 100 according to the estimated period. Asset management can be performed. The server 105 may determine the priority for updating the power cable based on the number of days until the insulation breakdown of the power cable, the importance of the power cable, and the cost / budget for the update. When determining the priority, the server 105 calculates the influence of external events (system operation, operation, weather, etc.) that can affect the partial discharge. For example, the server 105 increases the priority of the power cable in an area where the probability of occurrence of lightning strikes is high, increases the priority of the power cable connected to a substation that can be opened and closed, or the power cable is dielectrically broken. The priority may be determined according to the degree of influence (such as the power failure range and the number of branches of the connected power cable). The installation position of the computer system 102 with respect to the power cable may be changed periodically or based on the maintenance result of the power cable.

  When the computer system 102 determines an abnormality in the power cable, the computer system 102 may instruct the adjacent computer system 102 to record or output measurement data at the time when the abnormality is determined. On the other hand, the computer system 102 may record measurement data according to a command other than the diagnostic computer system such as a server. As a result, even if the position where there is a possibility that an oil gap may occur in the power cable is farther than the computer system 102 that has determined the abnormality, the measurement data can be recorded in the computer system 102 at the position where the oil gap is likely to exist. . In order to allow the computer system 102 to instruct the other computer systems 102 to record and output measurement data, the network 106 may have a real-time communication method. The computer system 102 may store a capacity corresponding to the worst guaranteed delay in the real-time communication method.

  The CPU 102 may repeat the flowchart of FIG. 5 at all times, and when the specific date and time are reached, the CPU 102 may end the flowchart when the storage capacity of the measurement data reaches a predetermined condition. The power equipment to which the present invention can be applied is not limited to a power cable. It may be a power device such as a circuit breaker, a transformer, or a disconnector that may generate a partial discharge.

DESCRIPTION OF SYMBOLS 100 ... Power cable, 101 ... Sensor, 102 ... Computer system, 103 ... Coaxial cable, 104 ... Storage, 105 ... Server, 106 ... Network, 110 ... Phase claim module, 112 ... Diagnostic module, 113 ... Measurement signal receiving module, DESCRIPTION OF SYMBOLS 114 ... Communication module, 115 ... Memory area, 118 ... Time synchronization module, 120 ... CPU, 121 ... LAN, 122 ... Data processing IC, 123 ... ADC, 124 ... Memory, 125 ... Non-volatile storage medium, 126 ... Bus

Claims (14)

A computer system for measuring a high frequency discharge signal from a power device to which AC power is applied, and evaluating the power device based on the high frequency discharge signal,
An electronic circuit for measuring the high-frequency discharge signal output from the sensor;
A controller for controlling the electronic circuit;
A memory for recording a high-frequency discharge signal measured by the electronic circuit;
With
The controller is
Controlling the electronic circuit to adjust the timing of measuring the high-frequency discharge signal based on an AC cycle;
Obtaining a high frequency discharge signal measured by the electronic circuit from the memory;
Based on the high frequency discharge signal, reproduce the high frequency discharge signal generated in the power equipment,
Computer system. The power device is a power cable;
The high-frequency discharge signal is generated by applying the AC power to a partial gap in an insulator of the power cable.
The computer system according to claim 1. Since the sampling frequency of the electronic circuit is smaller than the frequency of the high-frequency discharge signal output from the sensor, the electronic circuit measures a part of all signals output from the sensor.
The computer system according to claim 1. The controller sets the cycle of the AC power in the electronic circuit as the AC cycle.
The computer system according to claim 1. Adjusting the timing at which the electronic circuit measures the high-frequency discharge signal based on the AC cycle,
A plurality of cycles among the AC cycles are set by the controller;
Adjusting the timing at which the electronic circuit measures the high-frequency discharge signal across the plurality of cycles;
including,
The computer system according to claim 1. Adjusting the timing at which the electronic circuit measures the high-frequency discharge signal includes shifting the phase at which the measurement of the high-frequency discharge signal is started based on the AC cycle.
The computer system according to claim 1. The controller is
Based on the reproduced discharge signal, diagnose the quality of the insulation performance of the power cable,
Output diagnostic results,
The computer system according to claim 1. Adjusting the timing at which the electronic circuit measures the high frequency discharge signal,
A plurality of cycles among the AC cycles are set by the controller;
The electronic circuit measuring the high-frequency discharge signal across the plurality of cycles;
Shifting the phase at which the electronic circuit starts measuring the high frequency discharge signal from the starting point of the cycle in each of the plurality of cycles;
including,
The computer system according to claim 1. A charge amount of each of a plurality of high-frequency discharge signals measured during the plurality of cycles;
The phase at which the high frequency discharge signal is measured with respect to the starting point of the cycle at which the high frequency discharge signal is measured,
On the basis of the,
The controller reproduces a high-frequency discharge signal generated in the electrical device by the AC power;
The computer system according to claim 8. The controller sets the number of cycles of the plurality of cycles to a value equal to or higher than a value obtained by dividing the frequency of the high-frequency discharge signal by the sampling frequency of the electronic circuit.
The computer system according to claim 8. The controller sets the phase shift amount based on a value obtained by dividing the sampling frequency of the electronic circuit by the number of cycles of the plurality of cycles.
The computer system according to claim 10. The controller is
The phase shift amount is set to be larger every cycle of the plurality of cycles,
The computer system according to claim 8. The controller is
The phase shift amount is increased randomly at every cycle of the plurality of cycles.
The computer system according to claim 8. A computer system is a method of measuring a high frequency discharge signal from a power device to which AC power is applied, and evaluating the power device based on the high frequency discharge signal,
Measuring the high frequency discharge signal output from a sensor by an electronic circuit of the computer system;
A controller of the computer system controlling the electronic circuit;
Recording the high frequency discharge signal measured by the electronic circuit in the memory by the controller;
With
The controller controlling the electronic circuit comprises:
Controlling the electronic circuit to adjust the timing of measuring the high-frequency discharge signal based on an AC cycle;
Obtaining a high frequency discharge signal measured by the electronic circuit from the memory;
Reproducing the high frequency discharge signal generated in the power device based on the high frequency discharge signal;
Comprising
A method of evaluating electronic equipment.