Electric signal detector, diagnosis device, partial discharge detection system, partial discharge detection method, and program

Abstract

To provide an electric signal detector, a diagnosis device, a partial discharge detection system, a partial discharge detection method, and a program, which can detect occurrence of partial discharges with high accuracy.SOLUTION: An electric signal detector comprises: a first reception unit 12 for receiving an electric signal generated in a cubicle 4; a wide-band filter F0 for extracting an electric signal of a first frequency band from the received electric signal; a plurality of narrow-band filers F1-F3 for extracting an electric signal of a frequency band which is a portion of the first frequency band; a selection switch 14 for selecting the wide-band filter F0 and one of the narrow-band filters F1-F3; a level determination unit 20 for determining whether or not the level of the electric signal extracted by the wide-band filter F0 is greater than or equal to a threshold level; and a control unit 22 for sequentially selecting the narrow-band filters F1-F3 by switching the selection switch 14 when the electric signal level is determined to be higher than or equal to the threshold level, and transmitting the electric signals extracted by the narrow-band filters F1-F3 to the diagnosis device 3 that diagnoses occurrence of a partial discharge.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to an electrical signal detection device, a diagnostic device, a partial discharge detection system, a partial discharge detection method, and a program. [Background technology]

[0002] For example, high-voltage circuits of 6600V or more are installed in cubicles installed in plants, substations, etc. Partial discharges can occur in high-voltage circuits due to insulation deterioration, etc. When partial discharges occur, they spread over time and eventually cause insulation breakdown. For this reason, when partial discharges occur, it is necessary to detect them as soon as possible and carry out repair work such as replacing parts.

[0003] As a partial discharge detection method, Patent Document 1 discloses a method in which an electric signal is measured by a sensor installed around an electric device such as a motor, the measured electric signal is analyzed, and the occurrence of partial discharge is detected based on the analysis results. Furthermore, it discloses that the occurrence of partial discharge is detected with high accuracy by removing noise contained in the measured electric signal. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] US Patent No. 2011 / 0172970 Summary of the Invention [Problem to be solved by the invention]

[0005] However, with the technology disclosed in Patent Document 1, although the electrical signal detected by the sensor is frequency-analyzed, it is difficult to determine with high accuracy whether or not a partial discharge is occurring from the spectrum data obtained by the frequency analysis, and an expert is required to make the determination. Furthermore, partial discharges occur in a wide variety of forms depending on the cause, and even experts have difficulty in determining the type of partial discharge. For this reason, there has been a problem in that the occurrence of partial discharges cannot be detected with high accuracy.

[0006] The present disclosure has been made in consideration of the above circumstances, and its purpose is to provide an electrical signal detection device, a diagnostic device, a partial discharge detection system, a partial discharge detection method, and a program that are capable of detecting the occurrence of partial discharge with high accuracy. [Means for solving the problem]

[0007] An electrical signal detection device according to one aspect of the present disclosure includes a first receiving unit that receives an electrical signal generated within electrical equipment, a wideband filter that extracts an electrical signal in a first frequency band from the electrical signal received by the first receiving unit, a plurality of narrowband filters that extract an electrical signal in a frequency band that is a portion of the first frequency band, a selection switch that selects one of the wideband filter and each narrowband filter, a level determination unit that determines whether the level of the electrical signal extracted by the wideband filter is equal to or greater than a threshold level, and a control unit that, when the level determination unit determines that the level of the electrical signal is equal to or greater than the threshold level, switches the selection switch to sequentially select each narrowband filter and controls the transmission of the electrical signal extracted by each narrowband filter to a diagnostic device that diagnoses the occurrence of partial discharge.

[0008] A diagnostic device according to one aspect of the present disclosure is a diagnostic device that diagnoses partial discharges in electrical equipment based on electrical signals extracted by a plurality of narrow-band filters in an electrical signal detection device, and includes: a data conversion unit that generates characteristic data indicating the relationship between the phase and signal strength of the electrical signals extracted by each narrow-band filter; and a discharge determination unit that determines the occurrence of partial discharges in the electrical equipment based on the characteristic data.

[0009] A partial discharge detection system according to one aspect of the present disclosure includes an electric signal detection device installed in an electric facility, and a diagnostic device capable of communicating with the electric signal detection device, wherein the electric signal detection device includes a first receiver that receives an electric signal generated in the electric facility, a wideband filter that extracts an electric signal in a first frequency band from the electric signal received by the first receiver, a plurality of narrowband filters that extract an electric signal in a frequency band that is a part of the first frequency band, a selection switch that selects one of the wideband filter and each narrowband filter, and a diagnostic device that can communicate with the electric signal extracted by the wideband filter. a level determination unit that determines whether a level of an electric signal is equal to or greater than a threshold level; and a control unit that, when the level determination unit determines that the level of the electric signal is equal to or greater than the threshold level, switches the selection switch to select each narrow-band filter in turn and controls the transmission of the electric signal extracted by each narrow-band filter to a diagnostic device that diagnoses the occurrence of partial discharge. The diagnostic device includes a data conversion unit that generates characteristic data indicating the relationship between the phase and signal strength of the electric signal extracted by each narrow-band filter, and a discharge determination unit that determines the occurrence of partial discharge in the electric equipment based on the characteristic data.

[0010] A partial discharge detection method according to one aspect of the present disclosure includes the steps of: a first receiving unit receiving an electrical signal generated in electrical equipment; a selection switch selecting a wideband filter and extracting an electrical signal of a first frequency band from the electrical signal received by the first receiving unit; a level determining unit determining whether the level of the electrical signal of the first frequency band is equal to or greater than a threshold level; and, when it is determined that the level of the electrical signal is equal to or greater than the threshold level, the selection switch sequentially selecting a plurality of narrowband filters and extracting an electrical signal of a frequency band that is a part of the first frequency band; a data converting unit generating characteristic data indicating the relationship between the phase and signal strength of the electrical signal extracted by each narrowband filter; and a discharge determining unit determining the occurrence of a partial discharge in the electrical equipment based on the characteristic data.

[0011] One aspect of the present disclosure is a program for causing a computer to function as the above-described diagnostic device. [Effects of the Invention]

[0012] According to the present disclosure, it is possible to detect the occurrence of partial discharge with high accuracy. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a schematic configuration diagram of a partial discharge detection system according to the first embodiment. [Figure 2] FIG. 2 is a block diagram showing a detailed configuration of the partial discharge detection system according to the first embodiment. [Figure 3] FIG. 3 is an explanatory diagram showing the frequency bands of the wideband filter F0 and the narrowband filters F1 to F3. [Figure 4A] FIG. 4A is a graph showing PRPS characteristics when a floating conductor partial discharge occurs in an electrical installation. [Figure 4B] FIG. 4B is a graph showing PRPD characteristics when a floating conductor partial discharge occurs in an electrical installation. [Figure 5A] FIG. 5A is a graph showing PRPS characteristics when a metal protrusion partial discharge occurs in electrical equipment. [Figure 5B] FIG. 5B is a graph showing PRPD characteristics when a metal protrusion partial discharge occurs in electrical equipment. [Figure 6A] FIG. 6A is a graph showing PRPS characteristics when a free particle partial discharge occurs in an electrical installation. [Figure 6B] FIG. 6B is a graph showing PRPD characteristics when a free particle partial discharge occurs in an electrical installation. [Figure 7A] FIG. 7A is a graph showing PRPS characteristics when insulation degradation partial discharge occurs in electrical equipment. [Figure 7B] FIG. 7B is a graph showing PRPD characteristics when insulation degradation partial discharge occurs in electrical equipment. [Figure 8]FIG. 8 is an explanatory diagram showing the occurrence of floating conductor partial discharge. [Figure 9] FIG. 9 is an explanatory diagram showing the occurrence of metal protrusion partial discharge. [Figure 10] FIG. 10 is an explanatory diagram showing the occurrence of partial discharge caused by free particles. [Figure 11] FIG. 11 is a flowchart showing the processing procedure of the partial discharge detection system according to the first embodiment. [Figure 12] FIG. 12 is a block diagram showing another configuration of the filter unit. [Figure 13] FIG. 13 is a block diagram showing a detailed configuration of the partial discharge detection system according to the second embodiment. [Figure 14] FIG. 14 is a schematic diagram of a partial discharge detection system according to the second embodiment. [Figure 15] FIG. 15 is a schematic configuration diagram of a partial discharge detection system according to a modified example of the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0014] [Description of the First Embodiment] Hereinafter, embodiments will be described with reference to the drawings. Fig. 1 is a schematic configuration diagram of a partial discharge detection system 100 according to a first embodiment, and Fig. 2 is a block diagram showing a detailed configuration of the partial discharge detection system 100. As shown in Fig. 1, the partial discharge detection system 100 includes an electric signal detection device 1 (first electric signal detection device) and a diagnostic device 3.

[0015] The electric signal detection device 1 is installed inside a cubicle 4 (electrical equipment) that houses a high-voltage circuit of, for example, 6600V or more. The diagnostic device 3 is installed in a base station that remotely monitors the status of the cubicle 4. The electric signal detection device 1 and the diagnostic device 3 can communicate via a wireless or wired network line. Various data detected by the electric signal detection device 1 is transmitted to the diagnostic device 3. The electric signal detection device 1 and the diagnostic device 3 may be integrated into one device. The diagnostic device 3 may be installed in a facility where a manager is stationed, such as a monitoring room installed near the cubicle.

[0016] As shown in FIG. 2, the electrical signal detection device 1 includes an antenna 11, a first receiving unit 12, a diagnostic signal generating unit 13, a selection switch 14 (first selection switch), a filter unit 15, a switching unit 16, an analog processing unit 17, an A / D conversion unit 18, a synchronization signal output unit 19, a level determination unit 20 (first level determination unit), a communication unit 21, and a control unit 22 (first control unit).

[0017] The antenna 11 receives electrical signals (for example, electromagnetic waves) generated inside and around the cubicle 4 .

[0018] The first receiving unit 12 receives an electrical signal generated within the cubicle 4 (inside the electrical equipment). The first receiving unit 12 extracts an electrical signal in a frequency band (300 to 3000 MHz) that is the UHF (Ultra High Frequency) band from the electrical signal received by the antenna 11.

[0019] The diagnostic signal generating unit 13 outputs a diagnostic signal for diagnosing whether the system is operating normally. For example, if no electrical signal is generated due to partial discharge, noise, or the like in the high-voltage circuit inside the cubicle 4, the first receiving unit 12 will not receive an electrical signal for a long period of time. The diagnostic signal generating unit 13 outputs a diagnostic signal, for example, if the first receiving unit 12 does not receive an electrical signal for a certain period of time. If the diagnostic signal is detected by the analog processing unit 17 described below, the system is determined to be normal.

[0020] The filter section 15 includes a plurality of band-pass filters (hereinafter abbreviated as "filters"). In this embodiment, an example in which four filters F0 to F3 are included will be described.

[0021] The filter F0 has a frequency band set to, for example, 300 to 2000 MHz. That is, the filter F0 is an example of a wideband filter (first wideband filter) that extracts electrical signals in a frequency band (first frequency band) of 300 to 2000 MHz from the electrical signals received by the first receiving unit 12. The filter F0 blocks electrical signals with frequencies other than the first frequency band.

[0022] The frequency band of the wideband filter is not limited to 300 to 2000 MHz, but may be wider or narrower than this.

[0023] The frequency band of filter F1 is set to 300 to 800 [MHz]. The frequency band of filter F2 is set to 900 to 1500 [MHz]. The frequency band of filter F3 is set to 1500 to 2000 [MHz]. Filters F1 to F3 are examples of narrow-band filters (first narrow-band filters) that extract an electrical signal of a frequency band that is a part of the electrical signal of a first frequency band (300 to 2000 [Hz]).

[0024] That is, as shown in FIG. 3, three frequency bands (narrow bands) are set for the first frequency band (300 to 2000 MHz). Here, 800 to 900 MHz is the frequency band used by mobile phones, and there is a high probability of noise occurring in this frequency band. Therefore, this range is excluded from the pass band of the narrow band filter. Note that the frequency bands used by mobile phones differ depending on the country or region of the world, so it is advisable to set the frequency bands to be excluded depending on the country or region. If the influence of mobile phones is not a consideration, it is not necessary to set a frequency band to exclude received signals.

[0025] In this embodiment, an example in which three narrow-band filters (filters F1 to F3) are installed will be described, but the number of narrow-band filters is not limited to three, and may be two or four or more.

[0026] The selection switch 14 (first selection switch) shown in Fig. 2 is installed on the input side of the filter unit 15. The selection switch 14 switches the input of four filters F0 to F3. That is, the selection switch 14 switches the input of the filter unit 15 so that the electrical signal extracted by the first receiving unit 12 is input to one of the filters F0 to F3. The selection switch 14 selects the filter F0 (wideband filter) and one of the filters F1 to F3 (narrowband filters).

[0027] The switching unit 16 switches the connection of the selection switch 14. Based on a control command output from the control unit 22, the switching unit 16 outputs a switching signal to the selection switch 14 so as to select one of the four filters F0 to F3.

[0028] The analog processing unit 17 performs peak hold processing at regular time intervals on the electrical signal that has passed through the filter unit 15. The analog processing unit 17 outputs peak value data at regular time intervals to the A / D conversion unit 18.

[0029] The synchronization signal output unit 19 outputs a synchronization signal used when the analog received signal is converted into a digital signal by the A / D conversion unit 18. The synchronization signal output unit 19 outputs a synchronization signal synchronized with a power supply frequency of 50 / 60 Hz, with a fixed time interval obtained by dividing one period (20 msec or 16.7 msec) into 128, to the A / D conversion unit 18. Note that the power supply frequency and the number of divisions into one period described above are merely examples, and other numerical values ​​may also be used.

[0030] The A / D conversion unit 18 converts the peak value data output from the analog processing unit 17 into a digital signal in synchronization with the synchronization signal. That is, it generates a digitized electrical signal. The electrical signal contains amplitude, phase, and time information at the peak value of the analog received signal. The A / D conversion unit 18 outputs the digitized electrical signal to the communication unit 21.

[0031] The level judgment unit 20 (first level judgment unit) acquires the peak value output from the analog processing unit 17 when the filter F0 is selected by the selection switch 14. Based on the acquired peak value, the level judgment unit 20 determines whether the peak value exceeds a preset threshold level. That is, the level judgment unit 20 determines whether the level of the electrical signal extracted by the filter F0 (wideband filter) is equal to or greater than a threshold level. The level judgment unit 20 outputs this judgment result to the control unit 22.

[0032] The communication unit 21 transmits the electrical signal digitized by the A / D conversion unit 18 to the diagnostic device 3 .

[0033] The control unit 22 (first control unit) comprehensively controls each component of the electric signal detection device 1. Specifically, the control unit 22 outputs a control command to the switching unit 16 to control the switching of the selection switch 14. The control unit 22 outputs a command to the communication unit 21 to transmit a digitized electric signal. The control unit 22 executes partial discharge detection processing when the level determination unit 20 determines that the peak value of the electric signal exceeds the threshold level.

[0034] Specifically, when executing the partial discharge detection process, the control unit 22 switches the selection switch 14 to sequentially select each of the narrow band filters F1 to F3. When filter F1 is selected, the filter F1 extracts an electrical signal in the frequency band of 300 to 800 MHz. When filter F2 is selected, the filter F2 extracts an electrical signal in the frequency band of 900 to 1500 MHz. When filter F3 is selected, the filter F3 extracts an electrical signal in the frequency band of 1500 to 2000 MHz. The electrical signals extracted by each of the filters F1 to F3 are digitized by the A / D conversion unit 18 and then transmitted to the diagnostic device 3 from the communication unit 21.

[0035] When the first receiving section 12 does not receive an electrical signal for a certain period of time, the control section 22 outputs a command to the diagnostic signal generating section 13 to output a diagnostic signal.

[0036] That is, when the level determination unit 20 determines that the level of the electrical signal is equal to or higher than the threshold level, the control unit 22 switches the selection switch 14 to sequentially select each of the filters F1 to F3 (narrow band filters), and controls the transmission of the electrical signal extracted by each of the filters F1 to F3 to the diagnostic device 3, which diagnoses the occurrence of partial discharge.

[0037] The diagnostic device 3 includes a communication unit 31, a data conversion unit 32, a storage unit 33, and a discharge determination unit .

[0038] The communication unit 31 receives the electrical signal transmitted from the communication unit 21 of the electrical signal detection device 1 .

[0039] The data conversion unit 32 generates PRPS data (Phase-Resolved Pulse Sequence) based on the electrical signal received by the communication unit 31. Furthermore, based on this PRPS data, it generates PRPD (Phase-Resolved Partial Discharge). As shown in FIG. 4A, for example, PRPS is three-dimensional data obtained by converting the electrical signal received by the communication unit 31, i.e., the electrical signal received by the first receiving unit 12 and digitized by the A / D conversion unit 18, into three factors: amplitude, phase, and time.

[0040] As shown in Fig. 4B, for example, the PRPD is data (characteristic data) obtained by converting the three-dimensional data of the PRPS shown in Fig. 4A into two-dimensional data. In Fig. 4B, the horizontal axis represents the phase (0° to 360°) of the AC voltage supplied to the cubicle 4, and the vertical axis represents the discharge amplitude. That is, the data conversion unit 32 generates characteristic data that indicates the relationship between the phase and signal strength of the electrical signal extracted by each of the filters F1 to F3 (narrow-band filters).

[0041] The storage unit 33 stores learned characteristic data that indicates the association between PRPD and partial discharge, which has been acquired in advance by machine learning. That is, the storage unit 33 stores machine-learned data that has been obtained by machine learning the correspondence between previously extracted characteristic data and partial discharge that occurs in the cubicle 4 (electrical equipment). Machine learning is a well-known technology, and a detailed description thereof will be omitted.

[0042] The discharge determination unit 34 performs AI (artificial intelligence) diagnosis based on the PRPD generated by the data conversion unit 32 and the learned PRPD stored in the memory unit 33, and determines whether or not a partial discharge has occurred inside the cubicle 4. That is, the discharge determination unit 34 determines the occurrence of a partial discharge based on the characteristic data generated based on the electrical signals extracted by each of the filters F1 to F3 (narrow band filters) and the machine learning data.

[0043] By analyzing PRPD, it is possible to infer the cause of partial discharge. However, in order to infer the cause of partial discharge using PRPD, a wealth of knowledge and experience is required. For this reason, in this embodiment, AI is used to analyze the cause of partial discharge.

[0044] Below, we will explain the types of partial discharges that occur within the cubicle 4 and the characteristics of PRPD for each type. Causes of partial discharge include floating conductor partial discharge, metal projection partial discharge, loose particle partial discharge, and insulation degradation partial discharge. Note that there are multiple other causes of partial discharges besides those mentioned above, but since the above four partial discharges account for the majority of all partial discharges, we will explain these four partial discharges below. The characteristics of each partial discharge in PRPD will be explained with reference to Figures 4A to 7B.

[0045] Fig. 4A is a diagram showing the PRPS when a floating conductor partial discharge occurs. Fig. 4B is a diagram showing the PRPD, which is a two-dimensional representation of the PRPS shown in Fig. 4A, in which the peak values ​​of the bar graph shown in Fig. 4A are plotted. Fig. 8 is an explanatory diagram showing the occurrence of a floating conductor partial discharge.

[0046] Floating conductor partial discharge is a partial discharge that occurs due to a floating defect. As shown in Figure 8, floating conductor partial discharge occurs when a foreign object 53 such as metal exists between a high-voltage electrode 51, which is insulated from its surroundings by an insulator 50, and a ground electrode 52, causing capacitive coupling. Causes of floating defects include loose bolts or washers used to secure the electrodes, poor contact in a circuit breaker or switch, peeling of insulator attached to metal, and accumulation of metallic trace substances on the surface of the insulator. Note that "HV" in Figure 8 refers to high voltage.

[0047] As shown in FIG. 4B, it can be seen that when a floating conductor partial discharge occurs, high discharge amplitudes occur in two phases (near 90° and 270°).

[0048] Fig. 5A shows the PRPS when a metal protrusion partial discharge occurs. Fig. 5B shows the PRPD, which is a two-dimensional representation of the PRPS shown in Fig. 5A, plotting the peak values ​​of the bar graph shown in Fig. 5A. Metal protrusion partial discharge is also called corona discharge. Fig. 9 is an explanatory diagram showing the occurrence of a metal protrusion partial discharge.

[0049] As shown in Figure 9, metal protrusion partial discharges are partial discharges that occur at sharp points. That is, a piece of metal with a sharp point acts as a high-voltage electrode 61 and faces a ground electrode 62, causing a partial discharge. Poor surface processing of metals is one example of a cause of metal protrusion partial discharges. Even if a metal surface appears smooth to the naked eye, sharp points may be visible under magnification.

[0050] As shown in FIG. 5B, when a metal protrusion partial discharge occurs, it is understood that the discharge is characterized by being concentrated in regions higher than phases 90° and 270°.

[0051] Fig. 6A is a diagram showing the PRPS when a free particle partial discharge occurs. Fig. 6B is a diagram showing the PRPD, which is a two-dimensional representation of the PRPS shown in Fig. 6A, in which the peak values ​​of the bar graph shown in Fig. 6A are plotted. Fig. 10 is an explanatory diagram showing the occurrence of a free particle partial discharge.

[0052] As shown in Fig. 10, a free particle partial discharge occurs when a conductive particle 65 exists between a high-voltage electrode 63 and a ground electrode 64. This discharge occurs when a strong electric field moves conductive particles inside a circuit breaker, switchgear, oil-filled transformer, gas insulated switchgear (GIS), etc.

[0053] As shown in FIG. 6B, when a partial discharge of free particles occurs, it is understood that the discharge occurs evenly in all phases.

[0054] Fig. 7A is a diagram showing the PRPS when an insulation degradation partial discharge occurs. Fig. 7B is a diagram showing the PRPD, which is a two-dimensional representation of the PRPS shown in Fig. 7A, and plots the peak values ​​of the bar graph shown in Fig. 7A. Insulation degradation partial discharge is a partial discharge that occurs when insulation deteriorates due to voids or surface contamination that occur in insulators provided in high-voltage circuits.

[0055] As shown in FIG. 7B, when insulation degradation partial discharge occurs, it is understood that the discharge is characterized by being concentrated at phases 0 to 90° and 180 to 270°, which are the rising edges of the voltage.

[0056] The discharge determination unit 34 shown in Fig. 2 refers to the PRPD graphs shown in Figs. 4B, 5B, 6B, and 7B described above, and determines, through AI diagnosis, whether or not a partial discharge has occurred in the high-voltage circuit within the cubicle 4. Furthermore, it determines the type of partial discharge. That is, the discharge determination unit 34 determines the occurrence of a partial discharge within the cubicle 4 (inside the electrical equipment) based on the characteristic data. Note that, in this embodiment, an example will be described in which the discharge determination unit 34 detects the occurrence of a partial discharge through AI diagnosis, but the occurrence of a partial discharge may also be detected by employing a diagnostic method other than AI diagnosis.

[0057] The operation of the partial discharge detection system 100 according to this embodiment will be described below with reference to the flowchart shown in FIG.

[0058] First, in step S11 of FIG. 11, the first receiving unit 12 extracts an electrical signal (for example, an electromagnetic wave) in the UHF band from the electrical signals received by the antenna 11.

[0059] In step S12, the control unit 22 outputs a control command to the switching unit 16 to connect the selection switch 14 to the filter F0. As a result, the selection switch 14 is connected to the input side of the filter F0. The electrical signals received by the first receiving unit 12 pass through the filter F0 and are input to the analog processing unit 17. That is, of the electrical signals in the UHF band received by the first receiving unit 12, electrical signals in the frequency band of 300 to 2000 [MHz] are input to the analog processing unit 17.

[0060] In step S13, the control unit 22 performs peak hold processing on the electrical signal input to the analog processing unit 17 to calculate a peak value. The level determination unit 20 determines whether the peak value exceeds the threshold level. If the peak value exceeds the threshold level (S13; YES), the process proceeds to step S14; if not (S13; NO), the process returns to step S12. In other words, if the electrical signals in the frequency band of 300 to 2000 MHz that have passed through the filter F0 do not include any electrical signals that exceed the threshold level, it is determined that no partial discharge has occurred within the cubicle 4, and the processes from step S14 onwards are not carried out.

[0061] In step S14, the control unit 22 sets the variable x to x=1.

[0062] In step S15, the control unit 22 outputs a control command to the switching unit 16 to connect the selection switch 14 to the filter Fx. Since x=1 initially, the selection switch 14 is connected to the filter F1. The electrical signal received by the first receiving unit 12 passes through the filter F1 and is input to the analog processing unit 17. That is, of the electrical signals received by the first receiving unit 12, electrical signals in the frequency band of 300 to 800 [MHz] are input to the analog processing unit 17.

[0063] The received signal input to the analog processing unit 17 undergoes peak hold processing and is then digitized by the A / D conversion unit 18. The digitized electrical signal is transmitted from the communication unit 21 to the diagnostic device 3. The communication unit 31 of the diagnostic device 3 receives this electrical signal.

[0064] In step S16, the data conversion unit 32 generates a three-dimensional PRPS based on the received digital signal, and converts it into a two-dimensional PRPD.

[0065] In step S17, the discharge determination unit 34 executes AI diagnosis. Specifically, the discharge determination unit 34 evaluates the relationship with the graphs of phase-amplitude characteristics for each partial discharge shown in Figures 4B, 5B, 6B, 7B, etc. based on the PRPD, and diagnoses whether a partial discharge has occurred in the high-voltage circuit. Furthermore, it determines the type of partial discharge (the four types of partial discharge mentioned above).

[0066] In step S18, the control unit 22 determines whether or not x=3, and if x=3 (S18; YES), the process proceeds to step S20, and if not (S18; NO), the process proceeds to step S19.

[0067] In step S19, the control unit 22 sets x = x + 1. Here, x = 2. Then, the process returns to step S15. Then, the process of steps S15 to S17 described above is performed for filter F2. That is, a PRPD is generated for an electrical signal in the frequency band of 900 to 1500 [MHz], and AI diagnosis is performed.

[0068] Thereafter, x is set to 3. That is, the processes of steps S15 to S17 described above are performed for filter F3. That is, a PRPD is generated for an electrical signal in the frequency band of 1500 to 2000 [MHz], and AI diagnosis is performed.

[0069] In step S20, the discharge determination unit 34 determines whether partial discharge has occurred in two or more of the PRPDs generated from the three narrowband electrical signals. Specifically, it determines whether partial discharge has occurred in two or more of the PRPDs with frequency bands of (300-800 MHz), (900-1500 MHz), and (300-800 MHz).

[0070] If it is determined that partial discharge has occurred in two or more (S20; YES), the process proceeds to step S22, and if not (S20; NO), the process proceeds to step S21.

[0071] In this embodiment, the case where the number of narrow-band filters is three (F1, F2, F3) is shown. When the number of narrow-band filters is N (N≧3), alarm information may be output when it is determined that a partial discharge has occurred in the electrical signals extracted by n (2≦n≦(N−1) or more) narrow-band filters.

[0072] In step S21, the discharge determination unit 34 determines whether or not a partial discharge has occurred in one of the PRPDs generated from the electrical signals extracted by the three filters F1 to F3. If a partial discharge has occurred in one of the PRPDs (S21; YES), the process proceeds to step S23; otherwise (S21; NO), the process proceeds to step S24.

[0073] In step S22, the discharge determination unit 34 outputs alarm information. The alarm information is information for notifying an operator that a partial discharge has occurred and that repairs such as part replacement are necessary, and for example, a process is executed to turn on a red lamp (not shown) and to notify the operator by sound such as a buzzer. Furthermore, the discharge determination unit 34 estimates the cause of each partial discharge shown in Figures 4B, 5B, 6B, and 7B, and notifies the operator of the cause of the partial discharge in addition to the occurrence of the partial discharge. Thereafter, this process ends.

[0074] In step S23, the discharge determination unit 34 outputs warning information. The warning information is information for informing the operator that there is a high possibility of partial discharge occurring within a short period of time, and for urging the operator to be careful, and for example, a process such as turning on a yellow lamp (not shown) is executed. Thereafter, this process ends.

[0075] In step S24, the discharge determination unit 34 determines that the electrical signal received by the first receiving unit 12 is noise, and does not output the attention information or alarm information, after which the process ends.

[0076] As described above, the electric signal detection device 1 of the partial discharge detection system 100 according to this embodiment includes a first receiving unit 12 that receives an electric signal generated within the cubicle 4 (inside the electrical equipment), a wideband filter F0 that extracts an electric signal of a first frequency band from the electric signal received by the first receiving unit 12, a plurality of narrowband filters F1 to F3 that extract an electric signal of a frequency band that is a part of the first frequency band, a selection switch 14 that selects one of the wideband filter F0 and each of the narrowband filters F1 to F3, a level determination unit 20 that determines whether the level of the electric signal extracted by the wideband filter F0 is equal to or greater than a threshold level, and a control unit 22 that, when the level determination unit 20 determines that the level of the electric signal is equal to or greater than the threshold level, switches the selection switch 14 to select each of the narrowband filters F1 to F3 in sequence, and controls the transmission of the electric signals extracted by each of the narrowband filters F1 to F3 to a diagnostic device 3 that diagnoses the occurrence of partial discharge.

[0077] The diagnostic device 3 is a diagnostic device that diagnoses partial discharges in the cubicle 4 based on electrical signals extracted by the plurality of narrow-band filters F1 to F3 in the electrical signal detection device 1, and includes a data conversion unit 32 that generates characteristic data indicating the relationship between the phase and signal strength of the electrical signals extracted by each narrow-band filter F1 to F3, and a discharge determination unit 34 that determines the occurrence of partial discharges in the cubicle 4 based on the characteristic data.

[0078] In this embodiment, when the electrical signal that has passed through the wideband filter F0 exceeds the threshold level, the selection switch 14 is switched sequentially to the narrowband filters F1, F2, and F3 to acquire the electrical signal that has passed through each of the filters F1 to F3. Then, a PRPD is generated based on each of the electrical signals that have passed through the filters F1 to F3, and AI diagnosis is performed on the PRPD with the learned data stored in the storage unit 33 to determine whether or not a partial discharge is occurring.

[0079] If a partial discharge is determined to be occurring in an electrical signal that has passed through two or more narrowband filters, alarm information can be output to prompt the operator remotely monitoring the system at the base station to take action such as replacing parts or repairing the system.

[0080] Furthermore, if it is determined that a partial discharge has occurred based on an electrical signal that has passed through one narrow-band filter, it is possible to notify an operator remotely monitoring at a base station that there is an increasing possibility that a partial discharge will occur in the near future by outputting warning information. In other words, if it is determined that a partial discharge has occurred based only on an electrical signal that has passed through one narrow-band filter, there are signs of a partial discharge, but the possibility that a partial discharge has actually occurred is low, so warning information is output.

[0081] If none of the narrowband filters F1 to F3 determines that a partial discharge has occurred, the high-level signal contained in the electrical signal that passed through the filter F0 is determined to be noise, thereby avoiding unnecessary partial discharge determination processing. Therefore, the occurrence of partial discharge can be notified to an operator stationed at a remote base station with high accuracy. Also, the operator's workload can be reduced.

[0082] The PRPD is generated based on the electrical signal digitized from the signal received by the first receiving unit 12, and the presence or absence of partial discharge is determined by AI diagnosis, so even an operator with low data analysis skills can grasp the occurrence of partial discharge through highly accurate analysis.

[0083] In this embodiment, in addition to detecting the occurrence of partial discharge, the type of partial discharge is also analyzed, so that when alarm information or attention information indicating the occurrence of partial discharge is issued, the operator can easily identify the cause of the partial discharge and can promptly carry out work such as repairs and part replacement.

[0084] In this embodiment, an example has been described in which the first receiving unit 12 receives radio waves in the UHF band, but frequencies in other bands such as VHF may also be received.

[0085] Furthermore, at least one of the wideband filter F0 and the narrowband filters F1 to F3 included in the filter unit 15 can be configured by connecting a bandpass filter and a bandstop filter in series.

[0086] For example, as shown in Figure 12, the wideband filter F0 is a series connection of a 300-2000 MHz band-pass filter F01 and an 800-900 MHz band-stop filter F02. The narrowband filter F1 is a series connection of a 300-1000 MHz band-pass filter F11 and an 800-900 MHz band-stop filter F12. The narrowband filter F2 is a series connection of a 1000-1500 MHz band-pass filter F21 and an 800-900 MHz band-stop filter F22.

[0087] With this configuration, it becomes possible to configure the filter section 15 using a bandpass filter and a bandstop filter that are widely used.

[0088] The first receiving unit 12, diagnostic signal generating unit 13, switching unit 16, analog processing unit 17, A / D conversion unit 18, level determining unit 20, control unit 22, and communication unit 21 that constitute the electrical signal detecting device 1 shown in Fig. 2 can be configured as an integrated computer including, for example, a central processing unit (CPU) and storage means such as RAM, ROM, and a hard disk. Similarly, the diagnostic device 3 shown in Fig. 1 can be configured as an integrated computer including, for example, a central processing unit (CPU) and storage means such as RAM, ROM, and a hard disk. The electrical signal detecting device 1 and the diagnostic device 3 may each execute a predetermined program to realize the functions shown in Fig. 2.

[0089] [Description of Modification of First Embodiment] Next, a description will be given of a modified example of the partial discharge detection system 100 according to the first embodiment described above. In the first embodiment described above, an example has been shown in which alarm information is output when it is determined that partial discharge has occurred in at least two of the three narrow-band filters F1 to F3.

[0090] In the modified example, alarm information is output when the same narrow band filter (e.g., filter F1) determines that a partial discharge has occurred continuously for a certain period of time (e.g., three hours) or more, when the same band filter determines that a partial discharge has occurred once or more times a day and this continues for a predetermined number of days (e.g., three days), or when the same band filter determines that a partial discharge has occurred a predetermined number of times (e.g., 20 times) or more a day. With this configuration, as with the first embodiment described above, it is possible to detect partial discharges occurring in the high-voltage circuit with high accuracy.

[0091] [Description of the Second Embodiment] Next, a second embodiment will be described. Fig. 13 is a block diagram showing the configuration of a partial discharge detection system 101 according to the second embodiment.

[0092] As shown in FIG. 13, a partial discharge detection system 101 according to the second embodiment differs from the first embodiment in that it includes an electric signal detection device 1A (second electric signal detection device) in addition to the electric signal detection device 1 (first electric signal detection device) shown in FIG. 2. Also, as shown in FIG. 14, the electric signal detection device 1 is installed inside a cubicle 4, and the electric signal detection device 1A is installed outside the cubicle 4. Another difference is that the electric signal detection device 1 includes a signal processing unit 26. The electric signal detection device 1A includes an antenna 11A, a second receiving unit 12A, a diagnostic signal generating unit 13A, a selection switch 14A (second selection switch), a filter unit 15A, a switching unit 16A, an analog processing unit 17A, an A / D conversion unit 18A, a level determination unit 20A (second level determination unit), and a control unit 22A (second control unit).

[0093] The filter unit 15A includes a wideband filter F0A (second wideband filter) and three narrowband filters F1A, F2A, and F3A (second narrowband filters).

[0094] Among the components of the electric signal detection device 1A, at least the antenna 11A and the second receiving unit 12A are installed outside the cubicle 4.

[0095] Each of the components 11A, 12A, 13A, 14A, 15A, 16A, 17A, 18A, 20A, and 22A of the electrical signal detection device 1A has the same function as each of the components 11, 12, 13, 14, 15, 16, 17, 18, 20, and 22 of the electrical signal detection device 1 described above.

[0096] The signal processing unit 26 extracts a differential signal between the digital signal output from the A / D conversion unit 18 of the electrical signal detection device 1 and the digital signal output from the A / D conversion unit 18A of the electrical signal detection device 1A. That is, the signal processing unit 26 extracts a differential signal between the electrical signal extracted by each of the narrow-band filters F1 to F3 (first narrow-band filters) and the electrical signal extracted by each of the narrow-band filters F1A to F3A (second narrow-band filters). Therefore, the communication unit 21 transmits the differential signal to the diagnostic device 3. The data conversion unit 32 generates characteristic data of the electrical signal extracted by the signal processing unit 26. The subsequent processing is the same as in the first embodiment described above.

[0097] In the second embodiment, it is possible to extract only the electrical signal generated within the cubicle 4 by removing the electrical signal received by the second receiving unit 12A outside the cubicle 4 from the electrical signal received by the first receiving unit 12 inside the cubicle 4. This makes it possible to remove electricity generated outside the cubicle 4, such as noise generated when arc welding is being performed nearby, noise caused by discharge in other nearby cubicles, and noise caused by various wireless devices. This makes it possible to detect the occurrence of partial discharge with higher accuracy.

[0098] 15 is an explanatory diagram showing a modified example of the partial discharge detection system according to the second embodiment. In the modified partial discharge detection system, electric signal detection devices 1, 1a, and 1b are installed inside a plurality of cubicles 4 (here, three cubicles 4, 4a, and 4b). When partial discharge detection signals are detected in all of the electric signal detection devices 1, 1a, and 1b, it is determined that a partial discharge has occurred in the cubicle equipped with the electric signal detection device of the three electric signal detection devices 1, 1a, and 1b that has the largest signal amplitude.

[0099] With this configuration, when a plurality of cubicles are installed adjacent to each other, it becomes possible to easily identify the cubicle in which partial discharge is occurring.

[0100] The present disclosure is not limited to the above-described embodiments, and various modifications are possible within the scope of the present disclosure. [Explanation of symbols]

[0101] 1 Electrical signal detection device (first electrical signal detection device) 1A Electrical signal detection device (second electrical signal detection device) 3 Diagnostic equipment 4 Cubicle (electrical equipment) 11, 11A Antenna 12 First receiving unit 12A Second receiving unit 13, 13A Diagnostic signal generator 14 Selection switch (first selection switch) 14A selection switch (second selection switch) 15, 15A filter section 16, 16A switching section 17, 17A Analog processing section 18, 18A A / D conversion section 19 Sync signal output section 20 Level determination unit (first level determination unit) 20A Level Judgment Unit (Second Level Judgment Unit) 21 Communications Department 22 control unit (first control unit) 22A Control section (second control section) 26 Signal Processing Section 31 Communications Department 32 Data conversion section 33 Storage section 34 Discharge determination section 100, 101 Partial discharge detection system F0 bandpass filter (wideband filter, first wideband filter) F0A Bandpass filter (second wideband filter) F1, F2, F3 Bandpass filters (narrow band filters, first narrow band filters) F1A, F2A, F3A bandpass filters (second narrowband filters)

Claims

1. a first receiving unit that receives an electrical signal generated in the electrical equipment; a wideband filter that extracts an electrical signal of a first frequency band from the electrical signal received by the first receiving unit; a plurality of narrowband filters for extracting electrical signals in a frequency band that is a portion of the first frequency band; a selection switch for selecting one of the wideband filter and each narrowband filter; a level determination unit that determines whether the level of the electrical signal extracted by the wideband filter is equal to or greater than a threshold level; a control unit that switches the selection switch to sequentially select each narrow band filter when the level determination unit determines that the level of the electrical signal is equal to or higher than the threshold level, and controls the electrical signal extracted by each narrow band filter to be transmitted to a diagnostic device that diagnoses the occurrence of partial discharge; An electrical signal detection device comprising:

2. A diagnostic device for diagnosing partial discharge in electrical equipment based on electrical signals extracted by a plurality of narrow-band filters in an electrical signal detection device, comprising: a data conversion unit that generates characteristic data indicating the relationship between the phase and signal strength of the electrical signal extracted by each narrowband filter; a discharge determination unit that determines occurrence of partial discharge in the electrical equipment based on the characteristic data; A diagnostic device comprising:

3. a storage unit that stores machine learning data obtained by machine learning the correspondence between the characteristic data extracted in the past and partial discharges occurring in the electrical equipment, The discharge determination unit determines the occurrence of the partial discharge based on characteristic data generated based on the electrical signals extracted by each narrowband filter and the machine learning data. The diagnostic device of claim 2 .

4. The discharge determination unit determines whether the partial discharge is a floating conductor partial discharge, a metal projection partial discharge, a free particle partial discharge, or an insulation degradation partial discharge based on the characteristic data. The diagnostic device according to claim 2 or 3.

5. a first electrical signal detection device installed in the electrical equipment; and a diagnostic device capable of communicating with the first electrical signal detection device, The first electrical signal detection device is a first receiving unit that receives an electrical signal generated within the electrical equipment; a first wideband filter that extracts an electrical signal of a first frequency band from the electrical signal received by the first receiving unit; a plurality of first narrowband filters that extract electrical signals in a frequency band that is a portion of the first frequency band; a first selection switch for selecting one of the first wideband filter and each of the first narrowband filters; a first level determination unit that determines whether the level of the electrical signal extracted by the first wideband filter is equal to or greater than a threshold level; a first control unit that, when the first level determination unit determines that the level of the electrical signal is equal to or higher than the threshold level, switches the first selection switch to sequentially select each of the first narrow-band filters and performs control to transmit the electrical signal extracted by each of the first narrow-band filters to a diagnostic device that diagnoses the occurrence of partial discharge; Equipped with The diagnostic device comprises: a data conversion unit that generates characteristic data indicating the relationship between the phase and signal strength of the electrical signal extracted by each narrowband filter; a discharge determination unit that determines occurrence of partial discharge in the electrical equipment based on the characteristic data; A partial discharge detection system comprising:

6. Further comprising a second electrical signal detection device; The second electrical signal detection device is a second receiving unit that receives an electrical signal generated outside the electrical equipment; a second wideband filter that extracts an electrical signal of a second frequency band from the electrical signal received by the second receiving unit; a plurality of second narrowband filters that extract electrical signals in a frequency band that is a portion of the first frequency band; a second selection switch for selecting one of the second wideband filter and each second narrowband filter; a second level determination unit that determines whether the level of the electrical signal extracted by the second wideband filter is equal to or greater than a threshold level; a second control unit that, when the second level determination unit determines that the level of the electrical signal is equal to or greater than the threshold level, switches the second selection switch to sequentially select each second narrowband filter and outputs the electrical signal extracted by each second narrowband filter to the first electrical signal detection device, the first electrical signal detection device further includes a signal processing unit that extracts a differential signal between the electrical signals extracted by each of the first narrowband filters and the electrical signals extracted by each of the second narrowband filters; The data conversion unit generates characteristic data of the electrical signal extracted by the signal processing unit. The partial discharge detection system of claim 5 .

7. N (N≧3) first narrowband filters are provided; The discharge determination unit outputs alarm information when determining that a partial discharge has occurred based on characteristic data calculated based on n (2≦n≦(N−1)) electrical signals extracted by first narrow-band filters out of the N electrical signals. The partial discharge detection system according to claim 5 or 6.

8. a step in which a first receiving unit receives an electrical signal generated in the electrical equipment; a selection switch selecting a wideband filter and extracting an electrical signal of a first frequency band from the electrical signal received by the first receiving unit; a step in which a level determination unit determines whether or not the level of the electrical signal in the first frequency band is equal to or greater than a threshold level; a selection switch sequentially selecting a plurality of narrow-band filters when the level of the electrical signal is determined to be equal to or greater than a threshold level, and extracting an electrical signal of a frequency band that is a part of the first frequency band; a step in which a data conversion unit generates characteristic data indicating a relationship between the phase and signal intensity of the electrical signal extracted by each narrowband filter; a step in which a discharge determination unit determines occurrence of partial discharge in the electrical equipment based on the characteristic data; A partial discharge detection method comprising:

9. A program that causes a computer to function as the diagnostic device according to claim 3.

Images