CN113227803A - Partial discharge detection device - Google Patents
Partial discharge detection device Download PDFInfo
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- CN113227803A CN113227803A CN201980085916.2A CN201980085916A CN113227803A CN 113227803 A CN113227803 A CN 113227803A CN 201980085916 A CN201980085916 A CN 201980085916A CN 113227803 A CN113227803 A CN 113227803A
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- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/12—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing
Abstract
A partial discharge detection device detects a partial discharge in an underground cable having a linear conductor that transmits power, an insulating layer that covers the periphery of the conductor, and a shield layer that is a conductor that covers the periphery of the insulating layer, the partial discharge detection device including: a signal detection unit that detects, as a detection signal, a change in current flowing through a shield layer of the underground cable or a change in potential of the shield layer; and a discharge detection section that detects a partial discharge in the underground cable based on the detection signal detected by the signal detection section, the discharge detection section including: a band-pass filter receiving the detection signal; and a storage unit that stores characteristic data relating to characteristics of the band-pass filter, wherein the discharge detection unit detects the partial discharge based on an output signal of the band-pass filter and the characteristic data in the storage unit.
Description
Technical Field
The present invention relates to a partial discharge detection device.
The present application claims priority based on japanese application No. 2019-18142 filed on 2/4 of 2019, the entire disclosure of which is incorporated herein by reference.
Background
Patent document 1 (japanese patent application laid-open No. 2011-237182) discloses a partial discharge determination device as described below. That is, the partial discharge determination device includes: a current detector that detects a current flowing through a measurement target line; a feature value deriving unit that derives a feature value from a current signal based on the current detected by the current detector; and a determination unit configured to determine that partial discharge has occurred in the previous line to be measured when it is determined, based on the feature amount derived by the feature amount deriving unit, that the current signal detected within the predetermined time has a plurality of vibration waveforms, and that the plurality of vibration waveforms includes a plurality of waveforms having substantially the same magnitude and opposite vibration directions.
Documents of the prior art
Patent document
Patent document 1: japanese patent laid-open publication No. 2011-237182
Patent document 2: japanese laid-open patent publication No. 10-78471
Patent document 3: japanese patent laid-open publication No. 2004-101418
Disclosure of Invention
(1) A partial discharge detection device of the present disclosure detects a partial discharge in an underground cable having a linear conductor that transmits power, an insulating layer that covers the periphery of the conductor, and a shield layer that is a conductor that covers the periphery of the insulating layer, the partial discharge detection device including: a signal detection unit that detects, as a detection signal, a change in current flowing through the shield layer or a change in potential of the shield layer; and a discharge detection section that detects a partial discharge in the underground cable based on the detection signal detected by the signal detection section, the discharge detection section including: a band-pass filter receiving the detection signal; and a storage unit that stores characteristic data relating to characteristics of the band-pass filter, wherein the discharge detection unit detects the partial discharge based on an output signal of the band-pass filter and the characteristic data in the storage unit.
One aspect of the present disclosure can be realized not only as a partial discharge detection device including such a unique processing unit but also as a partial discharge detection system including a partial discharge detection device. Further, an aspect of the present disclosure can be implemented as a semiconductor integrated circuit that realizes part or all of the partial discharge detection apparatus.
Drawings
Fig. 1 is a diagram showing a configuration of a power transmission system according to a first embodiment of the present invention.
Fig. 2 is a diagram showing an example of the configuration of an underground cable used in the power transmission system according to the first embodiment of the present invention.
Fig. 3 is a diagram showing an example of a method of connecting underground cables used in a normal connection section of a power transmission system according to a first embodiment of the present invention.
Fig. 4 is a diagram showing an example of a connection method of underground cables used in an insulated connection portion of a power transmission system according to a first embodiment of the present invention.
Fig. 5 is a diagram showing another example of a connection method of underground cables used in an insulated connection portion of a power transmission system according to the first embodiment of the present invention.
Fig. 6 is a diagram showing a configuration of a partial discharge detection system according to a first embodiment of the present invention.
Fig. 7 is a diagram showing a configuration of a partial discharge detection device according to a first embodiment of the present invention.
Fig. 8 is a diagram showing a configuration of a CT in the partial discharge detection apparatus according to the first embodiment of the present invention.
Fig. 9 is a diagram showing another example of the configuration of the partial discharge detection device according to the first embodiment of the present invention.
Fig. 10 is a diagram showing an example of mounting a metal foil electrode in the partial discharge detection device according to the first embodiment of the present invention.
Fig. 11 is a diagram showing a configuration of a discharge detection unit in the partial discharge detection device according to the first embodiment of the present invention.
Fig. 12 is a diagram showing an example of an impulse response waveform of a BPF (Band-Pass Filter) in the discharge detector according to the first embodiment of the present invention.
Fig. 13 is a diagram showing the calculation result obtained by the discharge detection unit in the partial discharge detection device according to the first embodiment of the present invention.
Fig. 14 is a diagram showing a configuration of a discharge detection unit in modification 1 of the partial discharge detection apparatus according to the first embodiment of the present invention.
Fig. 15 is a diagram showing a configuration of a discharge detection unit in a partial discharge detection device according to a second embodiment of the present invention.
Detailed Description
Conventionally, a technique has been proposed in which partial discharge in an underground cable is detected and deterioration of an insulating layer is detected at an early stage based on the detection result of the partial discharge.
[ problem to be solved by the present disclosure ]
A technique capable of more accurately detecting partial discharge in an underground cable than the technique described in patent document 1 is desired.
The present disclosure has been made to solve the above-described problems, and an object thereof is to provide a partial discharge detection apparatus capable of more accurately detecting a partial discharge in an underground cable.
[ Effect of the present disclosure ]
According to the present disclosure, partial discharge in an underground cable can be more accurately detected.
[ description of embodiments of the invention of the present application ]
First, the description will be given by taking the contents of the embodiments of the present invention.
(1) A partial discharge detection device according to an embodiment of the present invention detects a partial discharge in an underground cable having a linear conductor that transmits electric power, an insulating layer that covers the periphery of the conductor, and a shield layer that is a conductor that covers the periphery of the insulating layer, the partial discharge detection device including: a signal detection unit that detects, as a detection signal, a change in current flowing through the shield layer or a change in potential of the shield layer; and a discharge detection section that detects a partial discharge in the underground cable based on the detection signal detected by the signal detection section, the discharge detection section including: a band-pass filter receiving the detection signal; and a storage unit that stores characteristic data relating to characteristics of the band-pass filter, wherein the discharge detection unit detects the partial discharge based on an output signal of the band-pass filter and the characteristic data in the storage unit.
In this way, by detecting the partial discharge based on the output signal of the band-pass filter receiving the signal based on the current flowing through the shield layer and the characteristic data of the band-pass filter, it is possible to sense whether or not the signal has a waveform corresponding to the characteristic data. This can reduce the influence of a noise component contained in the current flowing through the shield layer, for example, and can sense the current waveform generated by the partial discharge. Therefore, in the partial discharge detection apparatus, the partial discharge in the underground cable can be detected more accurately. In general, an ADC capable of performing high-speed sampling at a sampling frequency of several GHz, for example, is required to detect an impulse signal generated by a partial discharge by digital signal processing. In contrast, with the configuration in which the above-described signal is analyzed via the band-pass filter, a relatively low-speed ADC corresponding to the pass band of the band-pass filter can be used, and the manufacturing cost can be reduced.
(2) Preferably, the characteristic data is an impulse response characteristic of the band pass filter.
With this configuration, a detection device capable of satisfactorily sensing a pulse-like current waveform generated in large quantities due to partial discharge can be realized.
(3) Preferably, the discharge detection unit includes a plurality of band pass filters having different pass bands, the storage unit stores the characteristic data of each of the plurality of band pass filters, and the discharge detection unit detects the partial discharge based on an output signal of at least one of the band pass filters and the corresponding characteristic data.
With such a configuration, for example, a band-pass filter appropriate for the environment in which the underground cable is installed can be selected to detect the partial discharge. Thus, partial discharge can be detected more accurately under various environments.
(4) Preferably, the discharge detection unit selects any one of the band-pass filters from the plurality of band-pass filters based on the detection signal current detected by the signal detection unit, and detects the partial discharge based on an output signal of the selected band-pass filter and the corresponding characteristic data.
With this configuration, for example, a bandpass filter having a passband in which the noise component is the smallest among the passbands of the plurality of bandpass filters in the current flowing through the shield layer can be selected to detect the partial discharge more accurately.
Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding portions are denoted by the same reference numerals, and description thereof will not be repeated. At least some of the embodiments described below may be arbitrarily combined.
< first embodiment >
[ constitution and basic operation ]
Fig. 1 is a diagram showing a configuration of a power transmission system according to a first embodiment of the present invention.
Referring to fig. 1, power transmission system 502 includes underground cables 10A, 10B, and 10C, normal connection units 41A and 41B, insulation connection units 42A and 42B, and ground connection units 43A and 43B. Hereinafter, each of the underground cables 10A, 10B, and 10C is also referred to as an underground cable 10, each of the ordinary connection portions 41A and 41B is also referred to as an ordinary connection portion 41, each of the insulating connection portions 42A and 42B is also referred to as an insulating connection portion 42, and each of the above- ground connection portions 43A and 43B is also referred to as an above-ground connection portion 43. The power transmission system 502 is provided in, for example, an underground portion in the power system.
The ground connection portion 43 includes cable terminations 11A, 11B, 11C. The underground cable 10 is connected to the cable terminals 11A, 11B, 11C at the above-ground connection portion 43. More specifically, the underground cable 10A is connected to the cable terminal 11A, the underground cable 10B is connected to the cable terminal 11B, and the underground cable 10C is connected to the cable terminal 11C.
The above-ground connection 43 is provided in a portion of the substation where the underground cable 10 is present on the ground, for example. The normal connection portion 41 and the insulation connection portion 42 are provided inside the service opening (manhole) 31.
Fig. 2 is a diagram showing an example of the configuration of an underground cable used in the power transmission system according to the first embodiment of the present invention.
Referring to fig. 2, the underground cable 10 is composed of a linear conductor 71 for transmitting electric power, an inner semiconductive layer 72 made of a semiconductive Ethylene-Propylene (EP) rubber, an insulator 73 made of EP rubber as an insulating layer, an outer semiconductive layer 74 made of a semiconductive tape, a conductive shield layer 75, and a sheath 76 made of a vinyl resin (vinyl) in this order from the center. That is, the inner semiconductive layer 72 covers the periphery of the conductor 71, the insulator 73 covers the periphery of the inner semiconductive layer 72, the outer semiconductive layer 74 covers the periphery of the insulator 73, the shield layer 75 as a conductor covers the periphery of the outer semiconductive layer 74, and the jacket 76 covers the periphery of the shield layer 75.
The conductor 71 in the underground cable 10 is used for power transmission, and a high voltage is applied thereto. The shield layer 75 is conductive, and the shield layer 75 is grounded in the middle of the underground cable 10. Therefore, the shield layer 75 has a lower voltage than the conductor 71.
In the power transmission system 502, a three-phase three-wire system is used as a power distribution system, for example. In power transmission system 502, underground cables 10A, 10B, and 10C are provided as three-phase underground cables 10.
Referring again to fig. 1, the shield 75 of each of the underground cables 10A, 10B, 10C is exposed at the cable terminations 11A, 11B, 11C. Terminals are provided at exposed portions of the shield layers 75, respectively.
For example, the underground cable 10 is constituted by a plurality of cables whose ends are connected to each other at the ordinary connection portion 41 and the insulating connection portion 42.
Fig. 3 is a diagram showing an example of a method of connecting underground cables used in a normal connection section of a power transmission system according to a first embodiment of the present invention. In fig. 3, for convenience of explanation, the conductor 71 and the shield layer 75 in the underground cable 10A are mainly shown. The following description is also applicable to the underground cable 10B and the underground cable 10C.
Referring to fig. 3, underground cables 10a1, 10a2 are connected in a common connection portion 41. In the ordinary connection portion 41, for example, the shield layers 75 of the underground cables 10a1, 10a2 are exposed at the connection portion of the conductors 71 of the underground cables 10a1, 10a 2.
In the ordinary connection portion 41, for example, the shield layer 75 of the underground cable 10a1 and the shield layer 75 of the underground cable 10a2 are connected by using a conductive wire (wire) 12.
When the shield layer 75 of the underground cable 10a1 and the shield layer 75 of the underground cable 10a2 are connected, for example, a terminal 81 is provided in an exposed portion of the shield layer 75 of the underground cable 10a 2. The terminal 81 may be provided at an exposed portion of the shield layer 75 of the underground cable 10a 1.
The terminal 81 is connected to the ground node 13 via a cable or the like, whereby the shield layer 75 of the underground cable 10A is grounded.
Fig. 4 is a diagram showing an example of a connection method of underground cables used in an insulated connection portion of a power transmission system according to a first embodiment of the present invention. In fig. 4, for convenience of explanation, the conductor 71 and the shield layer 75 in the constitution of the underground cable 10A are mainly shown. The following description is also applicable to the underground cable 10B and the underground cable 10C.
Referring to fig. 4, underground cables 10a1, 10a2 are connected in an insulation connection 42. In the insulating connection unit 42, for example, the shield layers 75 of the underground cables 10a1 and 10a2 are exposed at the connection portions between the conductors 71 of the underground cables 10a1 and 10a2, and terminals 81 and the like are provided at the exposed portions, respectively.
In the insulating connection portion 42, in the case where the conductor 71 of the underground cable 10a1 and the conductor 71 of the underground cable 10a2 are connected, for example, the terminal 81 in the underground cable 10a1 and the terminal 81 in the underground cable 10a2 are wired using the wire rod 12, whereby the shield layer 75 of the underground cable 10a1 and the shield layer 75 of the underground cable 10a2 are connected.
Fig. 5 is a diagram showing another example of a connection method of underground cables used in an insulated connection portion of a power transmission system according to the first embodiment of the present invention.
Referring to fig. 5, in the insulating connection portion 42, the underground cables 10a1, 10a2 are connected, the underground cables 10B1, 10B2 are connected, and the underground cables 10C1, 10C2 are connected. In the insulating connection portion 42, for example, the shield layers 75 of the underground cables 10a1, 10a2 are exposed at the connection portions between the conductors 71 of the underground cables 10a1, 10a2, the shield layers 75 of the underground cables 10B1, 10B2 are exposed at the connection portions between the conductors 71 of the underground cables 10B1, 10B2, the shield layers 75 of the underground cables 10C1, 10C2 are exposed at the connection portions between the conductors 71 of the underground cables 10C1, 10C2, and terminals 81 and the like are provided at the exposed portions.
In the insulating connection portion 42, for example, the terminal 81 of the underground cable 10a1 and the terminal 81 of the underground cable 10B2 are connected by the wire 12, the shield layer 75 of the underground cable 10a1 and the shield layer 75 of the underground cable 10B2 are connected, the terminal 81 of the underground cable 10B1 and the terminal 81 of the underground cable 10C2 are connected by the wire 12, the shield layer 75 of the underground cable 10B1 and the shield layer 75 of the underground cable 10C2 are connected, and the terminal 81 of the underground cable 10C1 and the terminal 81 of the underground cable 10a2 are connected by the wire 12, and the shield layer 75 of the underground cable 10C1 and the shield layer 75 of the underground cable 10a2 are connected.
In this manner, in the power transmission system 502, the underground cables 10 may also be connected in the form of cross-connections (cross-bonds) at the insulation connection portions 42.
[ partial discharge detection device ]
Fig. 6 is a diagram showing a configuration of a partial discharge detection system according to a first embodiment of the present invention. In fig. 6, the underground cable 10A among the underground cables 10 is mainly shown for convenience of explanation. The following description is also applicable to the underground cable 10B and the underground cable 10C.
Referring to fig. 6, a partial discharge detection system 501 includes partial discharge detection devices 500A and 500B. The partial discharge detection devices 500A and 500B are used in an electric power system including the underground cable 10. Hereinafter, each of the partial discharge detection devices 500A, 500B is also referred to as a partial discharge detection device 500.
The partial discharge detection device 500 is provided corresponding to the insulation connection portion 42, for example. In the example shown in fig. 6, the partial discharge detection device 500A is provided corresponding to the insulating connection portion 42A, and the partial discharge detection device 500B is provided corresponding to the insulating connection portion 42B.
The partial discharge detection devices 500A, 500B detect partial discharge of the underground cable 10.
For example, the underground cable 10A is equipped with a power coil. Induced current generated by the current flowing through the conductor 71 of the underground cable 10 flows to the power coil. Thus, the power coil can take out the current. The partial discharge detection device 500 operates by power obtained from a power supply coil, for example.
[ constitution of partial discharge detecting device ]
Fig. 7 is a diagram showing a configuration of a partial discharge detection device according to a first embodiment of the present invention.
Referring to fig. 7, the partial discharge detection device 500 includes a signal detection unit 120 and a discharge detection unit 300.
The signal detection section 120 detects a change in the current flowing through the shield layer 75 of the underground cable 10 as a detection signal. More specifically, the signal detection unit 120 detects an induced current of a current flowing through the shield layer 75 of the underground cable 10.
[ Signal detection part ]
The signal detection unit 120 includes a Current Transformer (CT) 100 and a signal output unit 110. The signal detection unit 120 detects an induced current at the insulated connection 42, which is a connection of the underground cable 10, for example.
Fig. 8 is a diagram showing a configuration of a CT in the partial discharge detection apparatus according to the first embodiment of the present invention.
Referring to fig. 8, the CT100 includes a toroidal core 101 and a winding 102. A winding 102 is wound around the toroidal core 101. The winding 102 is connected to the signal output section 110.
The CT100 is mounted, for example, such that the conductive cable 53 penetrates the toroidal core 101. The conductive cable 53 is, for example, a wire 12.
More specifically, referring again to fig. 4 and 6, the CTs 100 of the partial discharge detection apparatuses 500A, 500B in the insulation connection portion 42 are assembled such that the wire rods 12 connecting the shield layer 75 of the underground cable 10A1 and the shield layer 75 of the underground cable 10A2 penetrate the toroidal core 101.
When current flows through the shield 75 and the conductive cable 53, induced current flows through the winding 102 by inductive coupling. The discharge detection unit 300 receives a detection signal as an analog signal corresponding to the induced current flowing through the winding 102 via the signal output unit 110.
The signal detection unit 120 may be configured to include an antenna instead of the CT100 and detect an electromagnetic wave emitted when a partial discharge occurs in the underground cable 10. The antenna is, for example, an antenna having a VHF band of 30MHz to 300MHz or a UHF band of 300MHz to 1GHz as a reception band, is connected to the signal output unit 110, and receives an electromagnetic wave based on a change in current flowing through the shield layer 75 of the underground cable 10.
The discharge detection unit 300 receives a detection signal, which is an analog signal corresponding to the electromagnetic wave received by the antenna, via the signal output unit 110.
[ other examples of partial discharge detection device ]
Fig. 9 is a diagram showing another example of the configuration of the partial discharge detection device according to the first embodiment of the present invention.
Referring to fig. 9, the partial discharge detection device 511 includes a signal detection unit 121 and a discharge detection unit 300.
The signal detection unit 121 detects a change in the potential of the shield layer 75 of the underground cable 10 as a detection signal.
More specifically, the signal detection unit 121 includes the metal foil electrodes 105 and 106 and the signal output unit 111. The signal detection unit 121 is electrostatically coupled to the shield layer 75 at, for example, an insulating connection unit 42 which is a connection unit of the underground cable 10.
Fig. 10 is a diagram showing an example of mounting a metal foil electrode in the partial discharge detection device according to the first embodiment of the present invention.
Referring to fig. 9 and 10, the metal foil electrodes 105 and 106 are connected to the signal output unit 111.
The metal foil electrodes 105, 106 are attached to the surface of the sheath 76 of the underground cable 10 on the opposite sides to each other via the insulating cylinder 77 in the insulating connection portion 42, for example. More specifically, for example, in the insulating connection portion 42 in which the underground cables 10a1 and 10a2 are connected, the metal foil electrode 105 is attached to the surface of the sheath 76 of the underground cable 10a1, and the metal foil electrode 106 is attached to the surface of the sheath 76 of the underground cable 10a 2.
The metal foil electrodes 105 and 106 may be attached so as to cover the outer periphery of the sheath 76 of the underground cable 10a 2. The position at which each metal foil electrode is attached and the number of metal foil electrodes are not limited, and three or more metal foil electrodes may be attached.
When current flows through the shield 75 and the conductive cable 53, induced current flows through the metal foil electrodes 105, 106 by inductive coupling. The signal detection unit 121 detects an induced current flowing through the metal foil electrodes 105 and 106. The discharge detection unit 300 receives a detection signal as an analog signal corresponding to a change in the potential of the shield layer 75 based on the induced current via the signal output unit 111.
[ discharge detection part ]
The discharge detection section 300 detects a partial discharge in the underground cable 10 based on the detection signal detected by the signal detection section 120 or 121. In more detail, the discharge detecting part 300 detects a partial discharge in the underground cable 10 based on the induced current detected by the signal detecting part 120 or 121.
Fig. 11 is a diagram showing a configuration of a discharge detection unit in the partial discharge detection device according to the first embodiment of the present invention.
Referring to fig. 11, the discharge detection unit 300 includes an HPF (High-Pass Filter) 301, an LNA (Low Noise Amplifier) 302, an ADC (Analog Digital Converter) 303, an FFT (Fast Fourier Transform) processing unit 304, a Filter processing unit 310, an AGC (Automatic Gain Control) Amplifier 305, an ADC306, a detection unit 320, a switch Control unit 330, and a storage unit 340.
The filter processing unit 310 includes an analog switch 311 and BPFs 312A, 312B, and 312C. Hereinafter, each of the BPFs 312A, 312B, 312C is also referred to as a BPF 312.
The HPF301 outputs a signal obtained by attenuating a component of the analog signal received via the signal output unit 110 or 111, which is equal to or lower than a predetermined frequency, to the LNA 302. The analog signal received via the signal output unit 110 or 111 contains a lot of noise in a frequency band of, for example, less than 1.6MHz superimposed on the transmission path of the underground cable 10 or the like. The HPF301 attenuates frequency components smaller than 1.6MHz, for example, thereby removing noise included in the analog signal received via the signal output unit 110 or 111.
The LNA302 amplifies the analog signal received from the HPF301 with a predetermined gain, and outputs the amplified analog signal to the ADC303 and the filter processing unit 310.
The ADC303 converts the analog signal received from the LNA302 into a digital signal and outputs the digital signal to the FFT processing unit 304.
The FFT processing unit 304 performs signal processing such as FFT on the digital signal received from the ADC303, and outputs the processed digital signal to the detection unit 320.
The detection unit 320 generates a spectrum of an analog signal output from the HPF301 based on the digital signal received from the FFT processing unit 304, and outputs the generated spectrum to the switch control unit 330.
The switch control unit 330 generates a switch control signal based on the frequency spectrum received from the detection unit 320, and outputs the generated switch control signal to the analog switch 311, thereby switching the analog switch 311.
The analog switch 311 switches the BPF312 of the output destination of the analog signal received from the LNA302 in accordance with the switch control signal received from the switch control unit 330.
The passbands of the three BPFs 312 are different, respectively. For example, the passband of the BPF312A is 5MHz or more and less than 10MHz, the passband of the BPF312B is 10MHz or more and less than 15MHz, and the passband of the BPF312C is 15MHz or more and less than 20 MHz.
The switch control unit 330 selects one BPF312 to be an output destination of the analog signal switched by the analog switch 311 from the three BPFs 312. More specifically, the switch control unit 330 determines the passband with the least noise component among the analog signals output from the LNA302 among the passbands of the three BPFs 312, and selects the BPF312 corresponding to the passband.
For example, the switch control section 330 selects any one of the BPFs 312 from the plurality of BPFs 312 based on the detection signal detected by the signal detection section 120 or 121. More specifically, the switch control unit 330 selects, based on the spectrum received from the detection unit 320, the BPF312 corresponding to the passband in which the signal level of the analog signal output from the LNA302 is lowest among the passbands of the three BPFs 312.
Here, the current waveform generated by the partial discharge is a surge waveform. The components of the impulse waveform in the above frequency spectrum are equally distributed in the pass band of each BPF312, and therefore, the difference in the spectral level (spectral level) in each pass band due to the components of the impulse waveform is negligibly small. Therefore, based on the above frequency spectrum, the pass band in which the signal level of the analog signal output from the LNA302 is the lowest among the pass bands of the respective three BPFs 312 can be regarded as the pass band in which the noise component is the lowest.
The switch control unit 330 outputs the switch control signal to the analog switch 311, thereby switching the output destination of the analog signal switched by the analog switch 311 to the selected BPF 312. The switch control unit 330 outputs selection information indicating the selected BPF312 to the detection unit 320.
For example, the switch control unit 330 selects the BPF312 periodically or aperiodically based on the spectrum received from the detection unit 320, and switches the analog switch 311 according to the selection result.
The switch control unit 330 is not limited to the configuration of switching the analog switch 311 based on the frequency spectrum received from the detection unit 320, and may be configured as follows: the digital signal received by the detection unit 320 from the ADC306 is monitored periodically or aperiodically, and the analog switch 311 is switched based on the value of the digital signal, that is, the change in the amount of the noise component included in the digital signal.
The BPF312 receives an analog signal corresponding to the induced current flowing through the winding 102 or the induced current flowing through the metal foil electrodes 105 and 106 as a detection signal detected by the signal detection unit 120 or 121. In more detail, the BPF312 receives the analog signal via the HPF301, the LNA302, and the analog switch 311. BPF312 outputs an analog signal in which a component outside its own passband, out of the frequency components of the analog signal received from analog switch 311, is attenuated, to AGC amplifier 305.
The AGC amplifier 305 amplifies the signal received from the BPF312 so that the output level of the analog signal to the ADC306 becomes constant, and outputs the amplified signal to the ADC 306.
ADC306 converts the analog signal received from AGC amplifier 305 into a digital signal and outputs the digital signal to detection unit 320.
The detection unit 320 detects a partial discharge in the underground cable 10 based on the output signal of at least one BPF312 of the three BPFs 312 and the corresponding characteristic data relating to the physical properties of the BPF 312. More specifically, the detection unit 320 detects the partial discharge in the underground cable 10 based on the output signal of the BPF312 selected by the switch control unit 330 and the characteristic data relating to the physical properties of the BPF 312.
For example, the detection unit 320 receives the digital signal S obtained by amplifying and digitally converting the analog signal output from the selected BPF312 from the ADC306, and performs an operation using the received digital signal S and the characteristic data of the BPF312, thereby detecting the partial discharge in the underground cable 10.
The storage unit 340 stores characteristic data relating to the characteristics of the three BPFs 312. More specifically, the storage unit 340 stores, as the characteristic data, pulse (pulse) response characteristics of the three BPFs 312, for example, an impulse (impulse) response waveform Imp.
The detection unit 320 acquires the impulse response waveform Imp of the BPF312 indicated by the selection information received from the switch control unit 330 from the storage unit 340, and performs an operation using the acquired impulse response waveform Imp and the digital signal S received from the ADC306, thereby detecting the partial discharge in the underground cable 10.
Some or all of the FFT Processing Unit 304, the detection Unit 320, and the switch control Unit 330 are realized by operating a Processor such as a CPU (Central Processing Unit) or a DSP (Digital Signal Processor) with software, for example. A part or all of the functions of the FFT processing unit 304, the detection unit 320, and the switch control unit 330 are realized by operating a processor such as a CPU or a DSP with software, for example.
Fig. 12 is a diagram showing an example of an impulse response waveform of the BPF in the discharge detection unit according to the first embodiment of the present invention.
Referring to fig. 12, the impulse response waveform Imp of the BPF312 is stored in the storage section 340 as a digital signal having the number of samples K in a period T1 from time T0 to time ta. For example, the impulse response waveform Imp is a waveform having one or more maximum values and one or more minimum values.
The detector 320 calculates the calculation value y (T) by multiplying the X-th value of the impulse response waveform Imp by the X-th value of the K sample values included in the digital signal S in the period T1 from the time T to the time T + T1 according to the following expression (1) and adding the K values obtained by the multiplication for each sample value.
[ numerical formula 1]
In equation (1), S (t) is the value of the digital signal S at time t.
Fig. 13 is a diagram showing the calculation result obtained by the discharge detection unit in the partial discharge detection device according to the first embodiment of the present invention. In fig. 13, the vertical axis represents voltage, and the horizontal axis represents time.
Referring to fig. 13, the detection unit 320 calculates the calculated value y (T) corresponding to each start time by shifting each start time of the period T1 by the amount of one sample of the digital signal S. The detection unit 320 may calculate the calculation value y (t) by multiplying the digital signal S by the impulse response waveform Imp every time the digital signal S of one sample is received from the ADC306, and the detection unit 320 may calculate the calculation value y (t) by accumulating a predetermined number, for example, K sample values of the digital signal S received from the ADC306 and multiplying each of the accumulated sample values by the impulse response waveform Imp.
For example, when the digital signal S does not include the impulse waveform in the period T1 from the time tk to the time tk + T1, the calculated value y (tk) is a value close to zero. On the other hand, when the digital signal S in the period T1 from the time tm to the time tm + T1 includes the impulse waveform, the calculated value y (tm) becomes a somewhat large value.
The detection unit 320 detects the partial discharge based on the calculated operation value y (t). For example, the storage unit 340 stores a threshold ThA of the calculated value y (t) for detecting partial discharge. The detector 320 compares the calculated value y (t) with the threshold ThA, and determines that partial discharge has occurred when the calculated value y (t) is equal to or greater than the threshold ThA.
The detection unit 320 calculates the level of the impact signal generated by the partial discharge. More specifically, for example, the storage unit 340 stores the gain of the LNA302 and the input/output ratio of the impulse response characteristic of the BPF 312. When the gain of AGC amplifier 305 can be monitored, detection unit 320 acquires the gain of LNA302 and the input/output ratio of the selected impulse response characteristic of BPF312 from storage unit 340, and calculates the level of the impulse signal generated by the partial discharge based on the gain of LNA302, the gain of AGC amplifier 305, the input/output ratio of the selected impulse response characteristic of BPF312, and calculated value y (t).
The detection unit 320 calculates the phase of the surge signal generated by the partial discharge in the high-voltage applied to the conductor 71 of the underground cable 10 (hereinafter, also referred to as a surge phase). More specifically, the detection unit 320 detects a 50Hz or 60Hz waveform of an induced current generated by a current flowing through the conductor 71, for example, via the power coil mounted on the underground cable 10 as described above. The detection section 320 detects a zero-cross point (zero-cross point) of the waveform of the high-voltage applied to the conductor 71 based on the detected waveform.
The detection unit 320 calculates the impulse phase based on the detected zero-cross point and the generation timing of the impulse signal due to the partial discharge. The detection unit 320 may be configured to acquire information on the high voltage applied to the conductor 71, for example, the zero cross information, by communication with a central monitoring device as an external device.
The detection unit 320 generates partial discharge information including the level, the impact phase, and the like of the impact signal generated by the detected partial discharge, and stores the generated partial discharge information in the storage unit 340. The detection unit 320 updates the threshold ThA, for example, by using a machine learning method, based on the partial discharge information stored in the storage unit 340.
[ modification 1]
Fig. 14 is a diagram showing a configuration of a discharge detection unit in modification 1 of the partial discharge detection apparatus according to the first embodiment of the present invention.
Referring to fig. 14, discharge detector 300A of modification 1 does not include ADC303 and filter processor 310 includes LPF313, as compared to discharge detector 300 shown in fig. 11. More specifically, discharge detection unit 300A includes HPF301, LNA302, FFT processing unit 304, filter processing unit 310, AGC amplifier 305, ADC306, detection unit 320, switch control unit 330, and storage unit 340. Discharge detector 300A is the same as discharge detector 300 shown in fig. 11, except for the following description.
The Filter processing unit 310 includes an analog switch 311, BPFs 312A, 312B, and 312C, and a Low Pass Filter (LPF: Low-Pass Filter) 313. The cutoff frequency of the LPF313 is, for example, a frequency below 1/2 of the sampling frequency of the ADC 306.
The switch control unit 330 selects the LPF313 periodically or aperiodically as a filter to be an output destination of the analog signal switched by the analog switch 311, and switches the output destination of the analog signal switched by the analog switch 311 to the LPF 313.
LPF313 outputs to AGC amplifier 305 an analog signal obtained by attenuating a component of the analog signal received from analog switch 311, the component being equal to or higher than a predetermined frequency.
The AGC amplifier 305 amplifies the signal received from the LPF313 and outputs the amplified signal to the ADC306 so that the output level of the analog signal to the ADC306 becomes constant.
ADC306 converts the analog signal received from AGC amplifier 305 into a digital signal and outputs the digital signal to FFT processing unit 304.
The FFT processing unit 304 performs signal processing such as FFT on the digital signal received from the ADC306, and outputs the processed digital signal to the detection unit 320.
The detection unit 320 generates a spectrum of an analog signal output from the LPF313 based on the digital signal received from the FFT processing unit 304, and outputs the generated spectrum to the switch control unit 330.
The switch control unit 330 selects one BPF312 to be used as an output destination of the analog signal switched by the analog switch 311 from the three BPFs 312 based on the spectrum received from the detection unit 320. The switch control unit 330 outputs the switch control signal to the analog switch 311, thereby switching the output destination of the analog signal switched by the analog switch 311 to the selected BPF 312. The switch control unit 330 outputs selection information indicating that the LPF313 is selected to the detection unit 320.
[ modification 2]
The partial discharge detection device 500 or 511 may be configured to operate using the power obtained by the CT100 or the metal foil electrodes 105 and 106.
For example, the partial discharge detection apparatus 500 or 511 operates using an induced current of a current flowing through the shielding layer 75 of the underground cable 10.
More specifically, a sheath current, which is an induced current generated by the influence of the electric current for power transmission flowing through the conductor 71 of the underground cable 10, flows through the shield layer 75 of the underground cable 10.
In the partial discharge detection system 501, the sheath current flowing through the shield layer 75 of the underground cable 10 can be extracted by providing the CT100 or the metal foil electrodes 105 and 106 in the underground cable 10.
The partial discharge detection device 500 or 511 includes a filter for passing a current having a frequency of 60Hz or less, for example. The partial discharge detection device 500 or 511 extracts a low frequency current of 50Hz or 60Hz using a filter from each extracted sheath current.
Then, the partial discharge detection device 500 or 511 rectifies and synthesizes the respective low-frequency currents thus extracted, thereby generating a power supply current sufficient to operate the partial discharge detection device 500 or 511. The partial discharge detection device 500 or 511 operates by the generated power supply current.
In the partial discharge detection device according to the first embodiment of the present invention, the filter processing unit 310 in the discharge detection unit 300 has a configuration including three BPFs 312, but the present invention is not limited to this configuration. The filter processing unit 310 may have a configuration including two or less BPFs 312, or may have a configuration including four or more BPFs 312.
In addition, the partial discharge detection device according to the first embodiment of the present invention is configured as follows: in the discharge detection unit 300, the storage unit 340 stores the impulse response waveform Imp as the characteristic data of the BPF312, and the detection unit 320 calculates the calculation value y (t) by multiplying the digital signal S by the impulse response waveform Imp in the storage unit 340. That is, the storage unit 340 stores a waveform of a sine wave of a frequency included in the pass band of the BPF 312. The detection unit 320 calculates the calculation value y (t) by multiplying the digital signal S by the waveform of the sine wave in the storage unit 340.
Further, the following configuration is also possible. That is, in the discharge detection unit 300, the storage unit 340 stores characteristic data other than the impulse response characteristic as characteristic data of the BPF 312. The detection section 320 detects the partial discharge based on the digital signal S and the characteristic data in the storage section 340.
In the partial discharge detection device according to the first embodiment of the present invention, the signal detection unit 120 or 121 detects an induced current at a connection portion of the underground cable 10 such as the insulation connection portion 42, but the present invention is not limited thereto. The signal detection unit 120 or 121 may detect the induced current in a portion other than the connection portion of the underground cable 10.
In the partial discharge detection device according to the first embodiment of the present invention, the discharge detection unit 300 includes the AGC amplifier 305, but the present invention is not limited to this. Discharge detector 300 may be configured to include a normal amplifier having no automatic gain control function instead of AGC amplifier 305.
In addition, the partial discharge detection device according to the first embodiment of the present invention is configured as follows: in the discharge detection unit 300, the switch control unit 330 selects one BPF312 to be an output destination of the analog signal switched by the analog switch 311 from among the three BPFs 312, and the detection unit 320 detects the partial discharge by an operation using the output of the selected BPF312, that is, the digital signal S received via the ADC306 and the corresponding impulse response waveform Imp. That is, the switch control unit 330 selects two or more BPFs 312 to be output destinations of the analog signals switched by the analog switch 311. The detection unit 320 performs an operation using the digital signal S and the corresponding impulse response waveform Imp for each selected BPF312, and detects a partial discharge based on the respective operation results.
In addition, the partial discharge detection device according to the first embodiment of the present invention is configured as follows: the signal detection unit 120 detects an induced current of a current flowing through the shield layer 75 of the underground cable 10 via the CT100, and the discharge detection unit 300 detects a partial discharge in the underground cable 10 based on the induced current detected by the signal detection unit 120, but the present invention is not limited to this, and may have the following configuration. That is, the signal detection unit 120 detects a change in the current flowing through the shield layer 75 as a detection signal via a current sensor different from the CT 100. The discharge detection section 300 detects a partial discharge in the underground cable 10 based on the detection signal detected by the signal detection section 120.
Further, a technique that can more accurately detect partial discharge in an underground cable is desired.
In contrast, the partial discharge detection apparatus according to the first embodiment of the present invention is used in an electric power system including the underground cable 10. The signal detection unit 120 or 121 detects a change in current flowing through the shield layer of the underground cable 10 or a change in potential of the shield layer 75 as a detection signal. The discharge detection section 300 detects a partial discharge in the underground cable 10 based on the detection signal detected by the signal detection section 120 or 121. The discharge detection unit 300 includes a BPF312 that receives the detection signal, and a storage unit 340 that stores characteristic data of the BPF 312. The discharge detection section 300 detects a partial discharge based on the output signal of the BPF312 and the characteristic data in the storage section 340.
In this way, by detecting the partial discharge based on the output signal of the BPF312 and the characteristic data of the BPF312, which receive the analog signal based on the current flowing through the shield layer 75, it is possible to sense whether or not the waveform corresponding to the characteristic data exists in the analog signal. This can reduce the influence of a noise component contained in the current flowing through the shield layer 75, for example, and can sense the current waveform generated by the partial discharge.
Therefore, in the partial discharge detection apparatus of the first embodiment of the present invention, the partial discharge in the underground cable 10 can be detected more accurately. In general, an ADC capable of performing high-speed sampling at a sampling frequency of several GHz, for example, is required to detect an impulse signal generated by a partial discharge by digital signal processing. In contrast, by the configuration in which the analog signal is analyzed through the BPF312, a relatively low-speed ADC corresponding to the passband of the BPF312 can be used, and the manufacturing cost can be reduced.
In the partial discharge detection device according to the first embodiment of the present invention, the storage unit 340 stores the impulse response characteristic of the BPF312 as characteristic data.
With this configuration, a detection device capable of satisfactorily sensing a pulse-like current waveform generated in large quantities due to partial discharge can be realized.
In the partial discharge detection device according to the first embodiment of the present invention, the discharge detection unit 300 includes a plurality of BPFs 312 having different pass bands. The storage unit 340 stores characteristic data of each of the plurality of BPFs 312. The discharge detection unit 300 detects a partial discharge based on the output signal of at least one of the BPFs 312 and the corresponding characteristic data.
With such a configuration, for example, an appropriate BPF312 corresponding to the installation environment of the underground cable 10 can be selected to detect the partial discharge. Thus, partial discharge can be detected more accurately under various environments.
In the partial discharge detection device according to the first embodiment of the present invention, the discharge detection unit 300 selects any one of the BPFs 312 from the plurality of BPFs 312 based on the detection signal detected by the signal detection unit 120 or 121, and detects a partial discharge based on the output signal of the selected BPF312 and the corresponding characteristic data.
With such a configuration, for example, the BPF312 having the pass band with the smallest noise component among the currents flowing through the shield layer 75 among the pass bands of the plurality of BPFs 312 can be selected to detect the partial discharge more accurately.
Next, another embodiment of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding portions are denoted by the same reference numerals, and description thereof will not be repeated.
< second embodiment >
The present embodiment relates to a partial discharge detection device using a digital filter instead of an analog filter, as compared with the partial discharge detection device of the first embodiment. The partial discharge detection device of the present embodiment is the same as the partial discharge detection device of the first embodiment except for the following description.
Fig. 15 is a diagram showing a configuration of a discharge detection unit in a partial discharge detection device according to a second embodiment of the present invention.
Referring to fig. 15, discharge detection unit 400 includes HPF301, LNA302, ADC303, FFT processing unit 304, filter processing unit 410, detection unit 320, switch control unit 330, and storage unit 340.
The filter processing unit 410 includes a switch 411 and BPFs 412A, 412B, and 412C as digital filters. Hereinafter, each of the BPFs 412A, 412B, 412C is also referred to as a BPF 412.
Some or all of the FFT processing unit 304, the detection unit 320, the switch control unit 330, and the filter processing unit 410 are realized by operating a processor such as a CPU or a DSP with software, for example. A part or all of the functions of the FFT processing unit 304, the detection unit 320, the switch control unit 330, and the filter processing unit 410 are realized by operating a processor such as a CPU or a DSP with software, for example.
The HPF301 outputs a signal obtained by attenuating a component of the analog signal received via the signal output unit 110 or 111, which is equal to or lower than a predetermined frequency, to the LNA 302.
The LNA302 amplifies an analog signal received from the HPF301 with a predetermined gain, and outputs the amplified analog signal to the ADC 303.
The ADC303 converts the analog signal received from the LNA302 into a digital signal and outputs the digital signal to the FFT processing unit 304 and the BPF 412.
The FFT processing unit 304 performs signal processing such as FFT on the digital signal received from the ADC303, and outputs the processed digital signal to the detection unit 320.
The detection unit 320 generates a spectrum of an analog signal output from the HPF301 based on the digital signal received from the FFT processing unit 304, and outputs the generated spectrum to the switch control unit 330.
The passbands of the three BPFs 412 are different, respectively. For example, the passband of the BPF412A is 5MHz or more and less than 10MHz, the passband of the BPF412B is 10MHz or more and less than 15MHz, and the passband of the BPF412C is 15MHz or more and less than 20 MHz.
The BPF412 outputs a digital signal in which a component outside its own passband, out of the frequency components of the digital signal received from the ADC303, is attenuated, to the switch 411.
The switch control unit 330 generates a switch control signal based on the frequency spectrum received from the detection unit 320, and outputs the generated switch control signal to the switch 411, thereby switching the switch 411.
The switch 411 selectively outputs the digital signal received from the BPF412 to the detection unit 320. More specifically, the switch 411 is switched among the following three according to the switch control signal received from the switch control unit 330: outputs the digital signal received from the BPF412A to the detection unit 320; outputs the digital signal received from the BPF412B to the detection unit 320; alternatively, the digital signal received from the BPF412C is output to the detection unit 320.
The switch control unit 330 selects one BPF412 among the three BPFs 412, which outputs a digital signal to the detection unit 320 via the switch 411. More specifically, the switch control unit 330 determines the passband with the least noise component among the digital signals output from the ADC303 among the passbands of the three BPFs 412, and selects the BPF412 corresponding to the passband.
For example, the switch control unit 330 selects, based on the spectrum received from the detection unit 320, the BPF412 corresponding to the passband in which the value of the digital signal output from the ADC303 is the smallest among the passbands of the three BPFs 412.
Here, the current waveform generated by the partial discharge is a surge waveform. The components of the impulse waveform in the above frequency spectrum are equally distributed in the pass band of each BPF412, and therefore, the difference in the spectral level in each pass band due to the components of the impulse waveform is negligibly small. Therefore, based on the above frequency spectrum, the pass band in which the value of the digital signal output from the ADC303 is the smallest among the pass bands of the respective three BPFs 412 can be regarded as the pass band in which the noise component is the smallest.
The switch control unit 330 outputs the switch control signal to the switch 411, thereby switching the BPF412 that outputs the digital signal to the detection unit 320 via the switch 411 to the selected BPF 412.
For example, the switch control unit 330 selects the BPF412 periodically or aperiodically based on the spectrum received from the detection unit 320, and switches the switch 411 according to the selection result.
The switch control unit 330 is not limited to the configuration of switching the switch 411 based on the spectrum received from the detection unit 320, and may be configured as follows: the digital signal received by the detection unit 320 from the switch 411 is monitored periodically or aperiodically, and the switch 411 is switched based on the value of the digital signal, that is, the change in the amount of noise component included in the digital signal.
The detection unit 320 detects the partial discharge in the underground cable 10 based on the output signal of the switch 411 and the characteristic data relating to the physical properties of the BPF412 selected by the switch control unit 330. The details of the method of detecting partial discharge by the detection unit 320 are the same as those described in the first embodiment.
In addition, a BPF control unit that controls the output of the BPF412 to the detection unit 320 may be used instead of the switch control unit 330 and the switch 411. That is, the BPF control unit selects the BPF412 corresponding to the passband in which the value of the digital signal output from the ADC303 is the smallest, based on the spectrum received from the detection unit 320. The BPF control unit outputs a control signal to each BPF412, thereby causing the selected BPF412 to start outputting a digital signal to the detection unit 320 and causing the other BPFs 412 to stop outputting a digital signal to the detection unit 320.
The detection unit 320 is configured to detect the partial discharge in the underground cable 10 based on the output signal of the switch 411 and the characteristic data relating to the physical properties of the BPF412, but is not limited to this. The detection unit 320 may be configured as follows: a portion of the spectrum made is extracted, and a partial discharge in the underground cable 10 is detected based on the extracted spectrum and characteristic data relating to the physical properties of the frequency band of the spectrum.
Other configurations and operations are the same as those of the partial discharge detection device according to the first embodiment, and therefore detailed description thereof will not be repeated here.
In the partial discharge detection device according to the second embodiment of the present invention, since the processor used for software processing of part or all of the units can be shared, the cost can be reduced.
The above-described embodiments should be considered in all respects as illustrative and not restrictive. The scope of the present invention is indicated by the claims, rather than the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are intended to be embraced therein.
The above description includes the features hereinafter appended.
[ additional notes 1]
A partial discharge detection device that detects a partial discharge in an underground cable having a linear conductor that transmits power, an insulating layer that covers the periphery of the conductor, and a shield layer that is a conductor that covers the periphery of the insulating layer, the partial discharge detection device comprising: a signal detection unit that detects, as a detection signal, a change in current flowing through a shield layer of the underground cable or a change in potential of the shield layer; and a discharge detection section that detects a partial discharge in the underground cable based on the detection signal detected by the signal detection section, the discharge detection section including: a band-pass filter receiving the detection signal; and a storage unit that stores an impulse response waveform of the band-pass filter, wherein the discharge detection unit detects the partial discharge based on an output signal of the band-pass filter and the impulse response waveform in the storage unit.
Description of the reference numerals
10: underground cable
11: cable terminal
12: wire rod
13. 15: ground node
31: access hole
41: common connection part
42: insulating connection
43: ground connection part
53: conductive cable
71: conductor
72: inner semi-conducting layer
73: insulator
74: outer semi-conducting layer
75: shielding layer
76: protective sleeve
77: insulating cylinder
81: terminal with a terminal body
100：CT
101: ring-shaped iron core
102: winding wire
105. 106: metal foil electrode
110. 111: signal output unit
120. 121: signal detection unit
300: discharge detection unit
301：HPF
302：LNA
303：ADC
304: FFT processing unit
305: AGC amplifier
306：ADC
310: filter processing unit
311: analog switch
312：BPF
313：LPF
320: detection part
330: switch control unit
340: storage unit
400: discharge detection unit
410: filter processing unit
411: switch with a switch body
412：BPF
500. 511: partial discharge detection device
501: partial discharge detection system
502: a power transmission system.
Claims (4)
1. A partial discharge detection device detects a partial discharge in an underground cable having a linear conductor that transmits electric power, an insulating layer that covers the periphery of the conductor, and a shield layer that is a conductor that covers the periphery of the insulating layer,
the partial discharge detection device is provided with:
a signal detection unit that detects, as a detection signal, a change in current flowing through the shield layer or a change in potential of the shield layer; and
a discharge detection section that detects a partial discharge in the underground cable based on the detection signal detected by the signal detection section,
the discharge detection unit includes:
a band-pass filter receiving the detection signal; and
a storage unit for storing characteristic data relating to the characteristics of the band-pass filter,
the discharge detection unit detects the partial discharge based on an output signal of the band-pass filter and the characteristic data in the storage unit.
2. The partial discharge detection apparatus according to claim 1,
the characteristic data is an impulse response characteristic of the band pass filter.
3. The partial discharge detection apparatus according to claim 1 or 2,
the discharge detection section includes a plurality of the band pass filters having different pass bands,
the storage unit stores the characteristic data of each of the plurality of band-pass filters,
the discharge detection unit detects the partial discharge based on an output signal of at least one of the band-pass filters and the corresponding characteristic data.
4. The partial discharge detection apparatus according to claim 3,
the discharge detection unit selects any one of the band-pass filters from the plurality of band-pass filters based on the detection signal detected by the signal detection unit, and detects the partial discharge based on an output signal of the selected band-pass filter and the corresponding characteristic data.
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| JP2019-018142 | 2019-02-04 | ||
| JP2019018142 | 2019-02-04 | ||
| PCT/JP2019/041839 WO2020161967A1 (en) | 2019-02-04 | 2019-10-25 | Partial discharge detection device |
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| JP (1) | JP6835300B2 (en) |
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| JPWO2022172541A1 (en) * | 2021-02-15 | 2022-08-18 |
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| JPWO2020161967A1 (en) | 2021-02-18 |
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| CN113227803B (en) | 2022-07-01 |
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