JP7520481B2 - Partial discharge detection device, partial discharge detection method, partial discharge detection system, and computer program - Google Patents

Description

Embodiments of the present invention relate to a partial discharge detection device, a partial discharge detection method, a partial discharge detection system, and a computer program.

As electrical equipment ages, the insulating performance of the insulators on the surface or inside the equipment deteriorates. When the insulating performance deteriorates, partial discharge occurs at the deteriorated points. If the deterioration of the insulating performance progresses further, insulation breakdown occurs. Insulation breakdown can cause serious accidents such as ground faults. For this reason, partial discharge detection is carried out during the maintenance of electrical equipment. Partial discharge detection devices detect partial discharge by capturing partial discharge signals and estimating the deterioration of the insulating performance from the signal size or frequency of occurrence.

Conventional partial discharge detection devices have been proposed that detect partial discharges from changes in the pulse current or surface potential flowing into the ground. However, the pulse current or surface potential is weak. Also, noise generated by peripheral devices is superimposed on the pulse current or surface potential. For this reason, it has sometimes been difficult to detect the pulse current or surface potential.

JP 2009-168489 A

The problem that the present invention aims to solve is to provide a partial discharge detection device, a partial discharge detection method, a partial discharge detection system, and a computer program that can detect partial discharges in electrical equipment with greater accuracy.

A partial discharge detection device according to an embodiment includes an antenna, a partial discharge determination unit , and a position identification unit . The antenna is composed of a plurality of conductors, and each of the plurality of conductors receives electromagnetic waves generated by partial discharge in an electrical device stored in a box. The partial discharge determination unit detects partial discharge by determining whether or not partial discharge has occurred in the electrical device based on the reception strength represented by an electrical signal generated from the electromagnetic waves. The antenna is stored in the box. The position identification unit identifies the position at which the partial discharge has occurred based on the reception strength for each of the plurality of conductors and the date and time at which the electrical signal was acquired.

FIG. 2 is a functional block diagram showing a functional configuration of the partial discharge detection device according to the embodiment. FIG. 2 is a perspective view of a switchboard in which the partial discharge detection device according to the embodiment is installed. 5 is a flowchart showing a process for determining the presence or absence of partial discharge and for identifying the location of the partial discharge according to the embodiment. FIG. 2 is a diagram illustrating a specific example of an antenna according to an embodiment. FIG. 4 is a diagram showing a specific example of an antenna mounting method according to the embodiment. FIG. 1 is a diagram showing one example of an antenna mounted on a distribution board.

The partial discharge detection device, partial discharge detection method, partial discharge detection system, and computer program according to the embodiments will be described below with reference to the drawings.

Figure 1 is a functional block diagram showing the functional configuration of a partial discharge detection device 100 according to an embodiment. The partial discharge detection device 100 is housed in a box that houses electrical equipment. The partial discharge detection device 100 includes one or more antennas 101. The antennas 101 are connected to a partial discharge determination device 103 by signal lines 102. The partial discharge detection device 100 detects partial discharges generated by electrical equipment based on electromagnetic waves received by the antennas 101.

The antenna 101 is made of a conductor such as aluminum, copper, or iron. The antenna 101 receives electromagnetic waves. The electromagnetic waves are generated, for example, by partial discharge in an electrical device. Partial discharge is generated, for example, by deterioration of the insulation performance of a circuit breaker that constitutes the electrical device. An electric signal is generated based on the electromagnetic waves received by the antenna 101. The electric signal is input to the partial discharge determination device 103 through the signal line 102. The electric signal represents the reception intensity obtained from the electromagnetic waves generated by partial discharge. The partial discharge determination device 103 determines the presence or absence of partial discharge based on the electric signal input from the antenna 101. The partial discharge determination device 103 functions as a device including a communication unit 104, an input unit 105, a display unit 106, a signal storage unit 107, and a control unit 108 by executing a partial discharge determination program. The antenna 101 may be, for example, a metal plate. The antenna 101 may be, for example, a thin plate or metal tape having a thickness of about 0.5 mm or less. The size of the antenna 101 is not limited and may be any size. The partial discharge detection device 100 in FIG. 1 includes multiple antennas 101, but is not limited to multiple antennas. For example, the partial discharge detection device 100 may be configured to include one antenna 101.

The communication unit 104 is a network interface. The communication unit 104 communicates with an external server via a network (not shown). The communication unit 104 may communicate using a communication method such as a wireless LAN (Local Area Network), a wired LAN, Bluetooth (registered trademark), or LTE (Long Term Evolution) (registered trademark).

The input unit 105 is configured using input devices such as a touch panel, a mouse, and a keyboard. The input unit 105 may be an interface for connecting the input device to the partial discharge detection device 100. In this case, the input unit 105 generates input data (e.g., instruction information indicating instructions to the partial discharge detection device 100) from an input signal input to the input device, and inputs the input data to the partial discharge detection device 100.

The display unit 106 is an output device such as a CRT (Cathode Ray Tube) display, a liquid crystal display, or an organic EL (Electro Luminescence) display. The display unit 106 may be an interface for connecting an output device to the partial discharge detection device 100. In this case, the display unit 106 generates a video signal from the video data and outputs the video signal to a video output device connected to the display unit 106.

The signal storage unit 107 is configured using a storage device such as a magnetic hard disk device or a semiconductor storage device. The signal storage unit 107 stores signal data. The signal data is generated based on electromagnetic waves received by the antenna 101. The signal data holds at least the date and time when the electrical signal was acquired and the reception strength represented by the electrical signal. Note that if the partial discharge detection device 100 has multiple antennas 101, the signal data may hold identification information of the antennas 101. The identification information may be any information that can identify the antenna 101.

The control unit 108 controls the operation of each unit of the partial discharge determination device 103. The control unit 108 is executed by a device equipped with a processor such as a CPU (Central Processing Unit) and a RAM (Random Access Memory). The control unit 108 executes a signal processing program to function as an electrical signal acquisition unit 109, an amplifier unit 110, a filter unit 111, a partial discharge determination unit 112, and a position identification unit 113.

The electrical signal acquisition unit 109 acquires the electrical signal input by the antenna 101. The electrical signal acquisition unit 109 associates the date and time when the electrical signal was acquired with the reception strength represented by the electrical signal. Note that if the partial discharge detection device 100 has multiple antennas 101, the electrical signal acquisition unit 109 associates the date and time when the electrical signal was acquired with the reception strength represented by the electrical signal and the antenna identification information.

The amplifier unit 110 amplifies the acquired electrical signal. The amplifier unit 110 outputs the amplified electrical signal to the filter unit 111. The filter unit 111 removes noise components superimposed on the electrical signal. The filter unit 111 is, for example, a low-pass filter that passes only a frequency band that includes a partial discharge signal from the electrical signals generated by each antenna 101. In this way, the filter unit 111 outputs the electrical signal from which noise has been removed to the partial discharge determination unit 112.

The partial discharge determination unit 112 acquires a partial discharge signal from the electric signal. Specifically, the partial discharge determination unit 112 detects partial discharge by determining whether or not a partial discharge signal is present based on the reception strength of the electric signal and a predetermined threshold. The predetermined threshold is determined in advance. For example, the partial discharge determination unit 112 may determine that a partial discharge signal is present when the reception strength of the electric signal is equal to or greater than the predetermined threshold. When the partial discharge determination unit 112 determines that a partial discharge signal is present, it records the date and time when the electric signal was acquired and the reception strength represented by the electric signal as signal data in the signal storage unit 107. Note that when the partial discharge detection device 100 has multiple antennas 101, the partial discharge determination unit 112 may record the date and time when the electric signal was acquired, the reception strength represented by the electric signal, and the identification information of the antenna as signal data in the signal storage unit 107.

When electromagnetic waves due to partial discharge are received by multiple antennas 101, the position identification unit 113 identifies the location of partial discharge occurrence. When it is determined that a partial discharge signal is "present," the position identification unit 113 identifies the location of partial discharge occurrence from the signal level of the electrical signal generated for each antenna 101 and the difference between the date and time when the electrical signal was acquired. The position identification unit 113 may use a known method to identify the location of partial discharge occurrence. For example, the position identification unit 113 may use a known method for identifying the location of partial discharge occurrence, which is to identify that the location of partial discharge occurrence is near the antenna 101 that has the largest signal level of the electrical signal indicating a partial discharge signal is "present" or that has the earliest date and time when the electrical signal was acquired.

Figure 2 is a perspective view of a switchboard 10 in which a partial discharge detection device 100 according to an embodiment is installed. Electrical equipment 11 is housed inside the switchboard 10. The electrical equipment 11 is composed of equipment such as a circuit breaker, a disconnecting switch, a current transformer, or a voltage transformer (none of which are shown). The electrical equipment 11 passes high voltage and large current from the outside via a power cable 12. The electrical equipment 11 has a function of cutting off the passage of electricity in the event of an abnormality. A ground electrode 13 is connected to the bottom of the switchboard 10. The switchboard 10 is one form of a box body.

Reference numeral 20 denotes the position where partial discharge occurred in a device (e.g., a circuit breaker) that constitutes electrical device 11. Reference numerals 21 to 25 denote examples of electromagnetic waves emitted by partial discharge. Note that the directions in which electromagnetic waves are emitted are not limited to the five directions of reference numerals 21 to 25. When partial discharge occurs, electromagnetic waves are emitted in all directions in space starting from the position where partial discharge occurred.

The partial discharge detection device 100 is housed inside the switchboard 10. The partial discharge detection device 100 detects partial discharges occurring inside the switchboard 10. In the case of FIG. 2, the partial discharge detection device 100 receives electromagnetic waves radiated from the position indicated by the reference symbol 20. In the case of FIG. 2, the antenna 101 is attached to the front door 10a. When the front door 10a is closed, the antenna 101 receives electromagnetic waves indicated by the reference symbol 22. The received electromagnetic waves are input to the partial discharge determination device 103 as an electrical signal via the signal line 102. The partial discharge determination device 103 determines whether or not a partial discharge has occurred based on the input electrical signal. The partial discharge detection device 100 may be attached, for example, to the inside of the front door 10a of the switchboard 10.

Figure 3 is a flowchart showing the process flow for determining the presence or absence of partial discharge and identifying its location in an embodiment. The antenna 101 of the partial discharge detection device 100 receives electromagnetic waves (step S101). The antenna 101 inputs the electromagnetic waves as an electrical signal to the partial discharge determination device 103. The electrical signal acquisition unit 109 acquires the input electrical signal (step S102). The amplifier unit 110 amplifies the acquired electrical signal (step S103). The filter unit 111 removes noise components superimposed on the electrical signal (step S104).

The partial discharge determination unit 112 determines whether the signal level of the electrical signal is greater than a predetermined threshold (step S105). If the signal level of the electrical signal is greater than the predetermined threshold (step S105: YES), the partial discharge determination unit 112 determines that a partial discharge signal is present in the electrical signal (step S106). If the partial discharge determination unit 112 determines that a partial discharge signal is present, it records the date and time when the electrical signal was acquired and the reception strength represented by the electrical signal as signal data in the signal storage unit 107 (step S107). If the location determination unit 113 determines that a partial discharge signal is present, it determines the location of the partial discharge occurrence from the difference between the reception strength represented by the electrical signal generated for each antenna 101 and the date and time when the electrical signal was acquired (step S108).

If the signal level of the electrical signal is equal to or lower than a predetermined threshold value (step S105: NO), the partial discharge determination unit 112 determines that there is no partial discharge signal in the electrical signal (step S109).

Figure 4 is a diagram showing a specific example of the antenna 101 of the embodiment. For example, as shown in Figure 4, the antenna 101 may be configured by arranging multiple metal pieces 101a to 101o. In this case, there is no limit to the number and size of the multiple metal pieces, and any number and size may be used. The metal pieces are, for example, conductors such as aluminum, copper, or iron. Each of the antennas 101a to 101o receives an electromagnetic wave. The received electromagnetic wave is input to the partial discharge determination device 103 via the signal line 102. By arranging multiple metal pieces in this way, the antenna 101 can receive electromagnetic waves with better sensitivity. In addition, when the antenna 101 shown in Figure 4 is provided on the switchboard 10, the position identification unit 113 can identify the occurrence position of partial discharge by attaching one antenna 101. Therefore, the position identification unit 113 can identify the occurrence position of partial discharge without providing multiple antennas 101 on the switchboard 10.

Figure 5 is a diagram showing a specific example of the installation of the antenna 101 of the embodiment. In Figure 5, the antenna 101 is provided on the inside of the six metal plates of the front door 10a, the top plate 10b, the back plate 10c, the bottom plate 10d, the first side plate 10e, and the second side plate 10f that constitute the switchboard 10. The antenna 101 receives electromagnetic waves while being provided on the inside of the six metal plates that constitute the switchboard 10. The antenna 101 may be an antenna composed of multiple metal pieces as shown in Figure 4. In Figure 5, one antenna 101 is provided on each of the six metal plates, but multiple antennas may be provided. In this case, the antennas 101 may be provided vertically, horizontally, or randomly on one side of the metal plate. In Figure 5, the antennas 101 are provided on each of the six metal plates, but they do not have to be provided on all of the six metal plates. For example, the antenna 101 does not have to be provided on the top plate 10b, and does not have to be provided on the back plate 10c. In this way, there is no limit to where the antenna 101 is provided and the number of antennas provided.

The antenna 101 is made of a thin metal plate or metal tape, so that it can be easily attached to the six metal plates of the front door 10a, top plate 10b, back plate 10c, bottom plate 10d, first side plate 10e, and second side plate 10f that constitute the switchboard 10. In addition, the antenna 101 made of a thin metal plate or metal tape can be attached to the metal plate in a shape other than a flat shape. The shape other than a flat shape may be, for example, a curved shape or a three-dimensional shape. In addition, the antenna 101 is attached to each inner surface of the switchboard 10, so that the electromagnetic waves generated by partial discharge can be received by the multiple antennas 101. The position identification unit 113 can identify the location of the partial discharge based on the difference between the reception strength represented by the electrical signal generated for each antenna 101 and the date and time when the electrical signal was acquired.

Figure 6 is a diagram showing a specific example of an antenna 101 attached to a switchboard 10. In Figure 6, an antenna 101 attached to a front door 10a is described as an example. A shielding material 30 is provided between the front door 10a and the antenna 101. The shielding material 30 blocks noise that is conducted to the antenna 101. The shielding material 30 blocks components in the same frequency band as the electromagnetic waves generated by partial discharge. The shielding material 30 may be a material that constitutes an inductance whose resistance value is high in the frequency band of the electromagnetic waves generated by partial discharge. The frequency band of partial discharge is from several tens of MHz to several hundreds of MHz. For example, a magnetic sheet or a plate-shaped ferrite core may be used for the shielding material 30. The shielding material 30 may be provided so as to surround the side of the antenna 101. The shielding material 30 is configured to be large enough that the antenna 101 does not come into contact with the front door 10a. The shielding material 30 may be provided by overlapping multiple types of materials.

In the partial discharge detection device 100 configured in this manner, the antenna 101 receives electromagnetic waves generated by partial discharge in an electrical device. Partial discharge occurs due to a deterioration in the insulating performance of the insulator of the electrical device. Since the shielding material 30 is provided between the antenna 101 and the switchboard 10, the antenna 101 can receive electromagnetic waves while noise from other devices is blocked. This allows the partial discharge detection device 100 to detect the presence or absence of partial discharge with higher accuracy. In addition, the antenna 101 can receive electromagnetic waves with multiple antennas by being configured with multiple metal pieces arranged in a row or by providing multiple antennas on the switchboard in which the electrical device is stored. When electromagnetic waves are received by multiple antennas, the position identification unit 113 identifies the occurrence position of partial discharge from the difference between the reception strength represented by the electrical signal for each antenna and the date and time when the electrical signal was acquired. This allows the presence or absence of partial discharge to be detected with higher accuracy.

(Modification)
The control unit 108 may be configured to further include a failure prediction unit. The failure prediction unit performs failure prediction of the electric device. When insulation deterioration of the electric device progresses, the frequency of partial discharge increases. For example, when the frequency of partial discharge detected by the partial discharge determination unit 112 becomes higher than a threshold value related to the frequency of partial discharge, the failure prediction unit may transmit an alarm issuance instruction to notify that the possibility of failure of the electric device is increasing. Furthermore, when insulation deterioration of the electric device progresses, the strength of the partial discharge signal becomes stronger. When the reception strength of the partial discharge becomes higher than a threshold value related to the reception strength, the failure prediction unit may transmit an alarm issuance instruction to notify that the possibility of failure of the electric device is increasing. Note that a predetermined threshold value may be used as the threshold value related to the frequency of partial discharge or the threshold value related to the signal strength.

The partial discharge determination unit 112 may be configured to transmit an alarm issuance instruction to notify the occurrence of partial discharge when it is determined that partial discharge is "present". In this case, the control unit 108 further includes an alarm unit. The alarm unit receives an alarm issuance instruction. The alarm unit performs alarm processing based on the received alarm issuance instruction. The alarm processing may be an alarm sound, or a message such as an email or SMS (Short Message Service) to a pre-specified destination. The alarm processing may be any processing that is pre-specified. In addition, partial discharge may occur at multiple positions in an electrical device. The position identification unit 113 identifies the positions of multiple partial discharges. When the positions of multiple partial discharges are identified by the position identification unit 113, the failure prediction unit may transmit an alarm issuance instruction to notify the occurrence of partial discharge at multiple positions. By performing the alarm processing, when partial discharge occurs, it becomes possible to more quickly eliminate the partial discharge.

The alarm unit may perform different alarm processing depending on the received alarm issuance instruction. For example, the alarm unit may be configured to transmit a message to an external device when it receives an alarm issuance instruction from the failure prediction unit to notify that the possibility of failure of the electrical equipment is increasing. The alarm unit may be configured to issue an alarm sound when it receives an alarm issuance instruction from the partial discharge determination unit 112 to notify that partial discharge is occurring. The alarm unit may be configured to transmit a message to an external device and issue an alarm sound when it receives an alarm issuance instruction to notify that partial discharge is occurring at multiple positions.

In this embodiment, the partial discharge detection device 100 has been described as a single device, but it may be configured as multiple devices. The partial discharge detection device 100 may be configured by a cloud computing system.

In each of the above embodiments, the electrical signal acquisition unit 109, the amplification unit 110, the filter unit 111, the partial discharge determination unit 112, and the position identification unit 113 are software functional units, but they may also be hardware functional units such as an LSI or an electrical circuit.

According to at least one of the embodiments described above, by having the antenna 101 and the position identification unit 113, the presence or absence of partial discharge can be detected with higher accuracy.

Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the gist of the invention. These embodiments and their modifications are within the scope of the invention and its equivalents as set forth in the claims, as well as the scope and gist of the invention.

10...distribution board, 11...electrical equipment, 12...power cable, 13...ground electrode, 30...shielding material, 100...partial discharge detection device, 101...antenna, 102...signal line, 103...partial discharge determination device, 104...communication unit, 105...input unit, 106...display unit, 107...signal storage unit, 108...control unit, 109...electrical signal acquisition unit, 110...amplification unit, 111...filter unit, 112...partial discharge determination unit, 113...position identification unit

Claims (8)

a plate-shaped antenna composed of a plurality of conductors, each of which receives an electric field component of an electromagnetic wave generated by partial discharge of an electrical device housed in a box, the antenna being attached to the box via a shielding material, the antenna having an inductance that has a relatively high reactance to electromagnetic waves of a lower frequency than the electromagnetic waves generated by the partial discharge in the same frequency band as the electromagnetic waves generated by the partial discharge, thereby blocking components of noise from other devices in the same frequency band as the electromagnetic waves generated by the partial discharge;
a partial discharge determination unit that detects partial discharge by determining whether or not partial discharge has occurred in the electrical equipment based on a reception intensity represented by an electrical signal generated from the electromagnetic waves;
a position identifying unit that identifies a position where the partial discharge has occurred based on the reception strength of each of the plurality of conductors and the date and time when the electrical signal is acquired,
The antenna is housed in the box.
Partial discharge detection device. The partial discharge detection device according to claim 1, further comprising an alarm unit that performs an alarm process to notify the occurrence of partial discharge when partial discharge is detected by the partial discharge determination unit. The partial discharge detection device according to claim 2, wherein the alarm unit performs the alarm process when the frequency or reception strength of partial discharges detected by the partial discharge determination unit is greater than a predetermined threshold value. The partial discharge detection device according to any one of claims 1 to 3, wherein the antenna receives the electromagnetic waves while being installed inside the six metal plates that make up the box body. The partial discharge detection device according to claim 4, wherein a shielding material is provided between the metal plate and the antenna to block electromagnetic waves in the same frequency band as the electromagnetic waves. a receiving step of receiving an electric field component of an electromagnetic wave generated by partial discharge of an electric device stored in a box via each of a plurality of conductors of an antenna;
a partial discharge determination step of detecting partial discharge by determining whether or not partial discharge has occurred in the electrical equipment based on a reception intensity represented by an electrical signal generated from the electromagnetic waves;
and a position identifying step of identifying a position where the partial discharge has occurred based on the reception strength and the date and time when the electrical signal is acquired for each of the plurality of conductors,
The antenna is
A plate-shaped antenna is configured with the plurality of conductors, and the plurality of conductors each receive an electric field component of an electromagnetic wave generated by partial discharge of an electrical device stored in the box,
The shielding material is attached to the box through the shielding material, which has an inductance that has a relatively high reactance to electromagnetic waves having a lower frequency than the electromagnetic waves generated by the partial discharge in the same frequency band as the electromagnetic waves generated by the partial discharge, thereby blocking noise components from other devices in the same frequency band as the electromagnetic waves generated by the partial discharge.
Partial discharge detection methods. a plate-shaped antenna composed of a plurality of conductors, each of which receives an electric field component of an electromagnetic wave generated by partial discharge of an electrical device housed in a box, the antenna being attached to the box via a shielding material, the antenna having an inductance that has a relatively high reactance to electromagnetic waves of a lower frequency than the electromagnetic waves generated by the partial discharge in the same frequency band as the electromagnetic waves generated by the partial discharge, thereby blocking components of noise from other devices in the same frequency band as the electromagnetic waves generated by the partial discharge;
a partial discharge determination unit that detects partial discharge by determining whether or not partial discharge has occurred in the electrical equipment based on a reception intensity represented by an electrical signal generated from the electromagnetic waves;
a position identifying unit that identifies a position where the partial discharge has occurred based on the reception strength of each of the plurality of conductors and the date and time when the electrical signal is acquired,
The antenna is housed in the box.
Partial discharge detection system. A computer program for controlling a computer of a partial discharge detection device including an antenna attached to a box via a shielding material, the antenna being made of a plurality of conductors, each of which receives an electric field component of an electromagnetic wave generated by partial discharge of an electrical device stored in the box, the antenna having an inductance that has a relatively high reactance to electromagnetic waves of a lower frequency than the electromagnetic waves generated by the partial discharge in the same frequency band as the electromagnetic waves generated by the partial discharge, thereby blocking components of noise from other devices in the same frequency band as the electromagnetic waves generated by the partial discharge,
a receiving step of receiving an electric field component of an electromagnetic wave generated by partial discharge of an electric device stored in the box through each of the plurality of conductors of the antenna;
a partial discharge determination step of detecting partial discharge by determining whether or not partial discharge has occurred in the electrical equipment based on a reception intensity represented by an electrical signal generated from the electromagnetic waves;
and a position identification step of identifying a position where the partial discharge has occurred based on the reception strength and the date and time when the electrical signal was acquired for each of the plurality of conductors.

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