JP2020112578A - Partial discharge detection device - Google Patents

Abstract

To improve detection precision of partial discharge.SOLUTION: A partial discharge detection device comprises a signal acquisition part, a first filter part, a second filter part, and a determination part. The signal acquisition part is provided at an accommodation member which accommodates electric equipment, and acquires a detection signal. The first filter part extracts a first detection signal included in the detection signal and having a frequency higher than a first frequency. The second filter part extracts a second detection signal included in the detection signal and having a frequency band between a second frequency and a third frequency. The determination part determines the presence of a partial discharge based upon the first detection signal and the second detection signal.SELECTED DRAWING: Figure 3

Description

The embodiment relates to a partial discharge detection device.

2. Description of the Related Art Partial discharge detection devices are known that detect partial discharge caused by damage to the inside of an electric device having an electric device and a box that houses the electric device.

JP, 2011-149896, A JP 2012-220209 A JP 2012-220208 A

However, there is a problem that the detection accuracy of the partial discharge of the partial discharge detection device cannot be said to be sufficient.

The embodiment is made in view of the above, and an object thereof is to provide a partial discharge detection device capable of improving the detection accuracy of partial discharge.

In order to solve the above-described problems and achieve the object, the partial discharge detection device of the embodiment includes a signal acquisition unit, a first filter unit, a second filter unit, and a determination unit. The signal acquisition unit is provided in a housing member that houses an electric device and acquires a detection signal. The first filter unit extracts a first detection signal having a frequency equal to or higher than the first frequency, which is included in the detection signal. The second filter unit extracts the second detection signal in the frequency band between the second frequency and the third frequency included in the detection signal. The determination unit determines the presence of partial discharge based on the first detection signal and the second detection signal.

FIG. 1 is a perspective view of an electric device system including the partial discharge detection device according to the first embodiment. FIG. 2 is an internal configuration diagram illustrating a circuit configuration of the electric device system according to the first embodiment. FIG. 3 is a block diagram showing the function of the processing unit of the partial discharge detection device of the first embodiment. FIG. 4 is a diagram illustrating a detection signal. FIG. 5 is a flowchart of the determination program executed by the control unit. FIG. 6 is a block diagram showing the function of the processing unit of the partial discharge detection device of the second embodiment. FIG. 7 is an overall configuration diagram of an electric device system including the partial discharge detection device of the third embodiment. FIG. 8 is an overall configuration diagram of an electric device system including the partial discharge detection device of the fourth embodiment. FIG. 9 is an overall configuration diagram of an electric device system including the partial discharge detection device of the fifth embodiment.

Similar components are included in the following exemplary embodiments and modifications. Therefore, in the following, similar components will be denoted by common reference numerals, and redundant description will be partially omitted. The parts included in the embodiments and modifications can be configured by replacing the corresponding parts in other embodiments and modifications. In addition, the configurations, positions, and the like of the parts included in the embodiments and the modified examples are the same as those in the other embodiments and the modified examples, unless otherwise specified.

The partial discharge detection device according to the embodiment includes a first detection signal and a second detection signal derived from the partial discharge extracted from the detection signal indicating the presence of the partial discharge caused by damage to the insulating material that molds the electric device of the electric device. It is determined and detected based on.

<First Embodiment>
FIG. 1 is a perspective view of an electric device system 10 having a partial discharge detection device 14 of the first embodiment. As shown in FIG. 1, the electric device system 10 includes an electric device 12 and a partial discharge detection device 14.

The electric device 12 includes a box body 20 that is an example of a housing member, an electric device 22, and a ground member 24.

The box body 20 includes a conductive material such as metal. The box body 20 is configured, for example, in the shape of a hollow rectangular parallelepiped having six flat surfaces. The box body 20 accommodates and holds the electric device 22 and the grounding member 24.

The electric device 22 is provided inside the box body 20. The electric device 22 is an electric component that electrically operates. The electric device 22 is, for example, a circuit breaker, a switch, a main circuit conductor, or the like.

The ground member 24 is provided inside the box body 20. The ground member 24 is connected to the ground potential such as the ground. The ground member 24 grounds the box body 20 and the electric device 22.

The partial discharge detection device 14 includes a signal acquisition unit 30, a transmission unit 32, and a processing unit 34.

The signal acquisition unit 30 is provided in the box body 20. The signal acquisition unit 30 is fixed or installed in the box body 20 via an insulating material, for example. The signal acquisition unit 30 includes, for example, an electrode. The signal acquisition unit 30 acquires a detection signal DS0 indicating an electrical change (for example, a change in surface potential) due to partial discharge.

The transmission unit 32 connects the signal acquisition unit 30 and the processing unit 34. An example of the transmission unit 32 is a coaxial cable. The transmission unit 32 transmits the detection signal DS0 acquired by the signal acquisition unit 30 to the processing unit 34.

The processing unit 34 acquires the detection signal DS0 from the signal acquisition unit 30 via the transmission unit 32. The processing unit 34 performs a process of determining and detecting the presence of partial discharge based on the detection signal DS0.

FIG. 2 is an internal configuration diagram illustrating a circuit configuration of the electric device system 10 according to the first embodiment. As shown in FIG. 2, the electric device 22 is connected to a power source 90 such as a commercial power source. The electric device 22 receives AC power from the power supply 90.

The electric device 22 and the box body 20 are connected to a ground member 24. As a result, the electric device 22 and the box body 20 are connected to the ground potential via the ground member 24. As a result, the electric device 22 and the box body 20 cause a current to flow between them and the ground potential via the ground member 24, as indicated by an arrow AR1.

The inside of the box 20 is filled with an insulating material such as air or resin. As a result, the electric device 22 is molded with the insulating material. The electric device 22 is arranged apart from the box body 20. As a result, a capacity is formed between the electric device 22 and the box body 20. As a result, as indicated by an arrow AR2, a current flows in a circuit including the electric device 22 and the box body 20. Further, the electromotive force generated by the current flowing through the box body 20 causes a current to flow to the partial discharge detection device 14, as indicated by an arrow AR3.

FIG. 3 is a block diagram showing the function of the processing unit 34 of the partial discharge detection device 14 of the first embodiment. As illustrated in FIG. 3, the processing unit 34 of the partial discharge detection device 14 includes a high-pass filter 40 that is an example of a first filter unit, a band-pass filter 42 that is an example of a second filter unit, and a control device 44. And an output unit 46.

The high pass filter 40 is connected to the signal acquisition unit 30 via the transmission unit 32. The high pass filter 40 receives the detection signal DS0 from the signal acquisition unit 30. The high-pass filter 40 extracts the first detection signal DS1 having a frequency equal to or higher than a predetermined first frequency included in the detection signal DS0 and passes the first detection signal DS1 and blocks the detection signal DS0 having a frequency lower than the first frequency. An example of the first frequency is 100 MHz. The high pass filter 40 is connected to the control device 44. The high pass filter 40 transmits the first detection signal DS1 to the control device 44.

The bandpass filter 42 is connected to the signal acquisition unit 30 via the transmission unit 32. The bandpass filter 42 receives the detection signal DS0 from the signal acquisition unit 30. The bandpass filter 42 extracts and passes the second detection signal DS2 included in the detection signal DS0, which is the frequency band for extraction that is the frequency band between the second frequency and the third frequency, and passes the signals other than the extraction frequency band. The detection signal DS0 of is cut off. The second frequency and the third frequency are lower than the first frequency. An example of the second frequency is 1 MHz. An example of the third frequency is 20 MHz. The bandpass filter 42 is connected to the control device 44. The bandpass filter 42 transmits the second detection signal DS2 to the control device 44.

The control device 44 has a control unit 50 and a storage unit 52. An example of the control device 44 is a computer such as a microcomputer.

The control unit 50 is, for example, an arithmetic unit including a processor such as a CPU (Central Processing Unit). The control unit 50 includes a first determination unit 54 and a second determination unit 56, which are examples of determination units. The first determination unit 54 and the second determination unit 56 determine and detect the presence of partial discharge based on the first detection signal DS1 and the second detection signal DS2 transmitted by the transmission unit 32. The control unit 50 functions as the first determination unit 54 and the second determination unit 56, for example, by reading the determination program stored in the storage unit 52. At least a part of the first determination unit 54 and the second determination unit 56 may be configured by hardware such as a circuit.

The first determination unit 54 extracts the start time ST, which is the time at which the intensity of either the first detection signal DS1 or the second detection signal DS2 becomes equal to or greater than a predetermined first intensity threshold Th1. The first determination unit 54 of the present embodiment extracts the start time ST when the intensity of the first detection signal DS1 becomes equal to or higher than the first intensity threshold Th1. The first determination unit 54 outputs the start time ST to the second determination unit 56.

When the intensity of the other one of the first detection signal DS1 and the second detection signal DS2 becomes equal to or higher than a predetermined second intensity threshold Th2 during the determination time JT from the start time ST, the second determination unit 56 causes partial discharge. Is determined to exist. The determination time JT is a time during which general partial discharge continues, and is, for example, several μ seconds. When the intensity of the second detection signal DS2 becomes equal to or higher than the second intensity threshold Th2 during the determination time JT from the start time ST, the second determination unit 56 of the present embodiment determines that the partial discharge exists. On the other hand, if the intensity of the second detection signal DS2 does not exceed the second intensity threshold Th2 during the determination time JT from the start time ST, the second determination unit 56 determines that there is no partial discharge. In this case, since the intensity of the second detection signal DS2 is often smaller than the intensity of the first detection signal DS1, the second intensity threshold Th2 is preferably smaller than the first intensity threshold Th1. The second determination unit 56 transmits the determination result, which is the result of determining the presence of partial discharge, to the output unit 46.

The storage unit 52 includes a storage device such as a RAM (Random Access Memory), a ROM (Read Only Memory), and a HDD (Hard Disk Drive). The storage unit 52 stores a program such as a determination program executed by the control unit 50, parameters used in executing the program, and the like. The storage unit 52 stores, for example, the determination time JT, the first strength threshold Th1, the second strength threshold Th2, and the like as parameters.

An example of the output unit 46 is an image display device such as a liquid crystal display. The output unit 46 acquires the determination result from the second determination unit 56 of the control unit 50. The output unit 46 displays and outputs an image showing the determination result of partial discharge. The output unit 46 may output the determination result by voice or the like.

FIG. 4 is a diagram illustrating a detection signal. As shown in FIG. 4, the signal acquisition unit 30 acquires the time change of the surface potential of the box body 20 as the detection signal DS0.

The high-pass filter 40 passes the first detection signal DS1 having a frequency of 100 MHz or higher, which is the first frequency, of the detection signal DS0 and transmits the first detection signal DS1 to the control unit 50. The bandpass filter 42 passes the second detection signal DS2 in the extraction frequency band between the second frequency of 1 MHz and the third frequency of 20 MHz, and transmits the second detection signal DS2 to the control unit 50.

In general, the partial discharge often occurs at a frequency twice the frequency of the AC power supplied from the power source 90 to the electric device 22 for several microseconds. The inventor of the present application measured each partial discharge of several microseconds generated by a plurality of types of electric devices 22. Therefore, the inventor of the present application considers that each partial discharge is derived from the first detection signal DS1 of 100 MHz (that is, the first frequency) or higher, which is considered to be derived from the electromagnetic wave, and the ground current flowing to the ground potential by the partial discharge. It has been found to include a second detection signal DS2 in the frequency band between 1 MHz (ie the second frequency) and 20 MHz (ie the third frequency). That is, the inventor of the present application has found that both the first detection signal DS1 and the second detection signal DS2 become strong in the time zone in which the partial discharge exists.

For example, the partial discharge exists in a time zone (a time zone indicated by a dotted line square in FIG. 4) in which the potentials (that is, the intensities) of both the first detection signal DS1 and the second detection signal DS2 are high. On the other hand, in the time zone shown by the dashed-dotted square in FIG. 4, only one of the first detection signal DS1 and the second detection signal DS2 has a high potential, so that partial discharge does not exist. As a result, the control unit 50 causes the second detection signal DS2 to become the second intensity threshold Th2 or more during the determination time JT from the start time ST when the intensity of the first detection signal DS1 becomes the first intensity threshold Th1 or more. In this case, it can be determined that partial discharge exists. In this way, the control unit 50 can determine the presence of partial discharge based on the intensities of the first detection signal DS1 and the second detection signal DS2.

FIG. 5 is a flowchart of the determination program executed by the control unit 50. The control unit 50 starts the process of the flowchart shown in FIG. 5 by reading the determination program from the storage unit 52.

As shown in FIG. 5, the first determination unit 54 of the control unit 50 acquires the first detection signal DS1 from the high pass filter 40 (S100). For example, the first determination unit 54 acquires the intensity of the potential of the first detection signal DS1 or the absolute value (that is, the magnitude) of the potential.

The first determination unit 54 acquires the first intensity threshold Th1 from the storage unit 52 and determines whether or not the intensity of the first detection signal DS1 is greater than or equal to the first intensity threshold Th1 (S102). When the first determination unit 54 determines that the intensity of the first detection signal DS1 is not equal to or higher than the first intensity threshold Th1 (S102: No), step S100 and subsequent steps are repeated. After that, the first determination unit 54 repeats steps S100 and S102 until the intensity of the first detection signal DS1 becomes equal to or higher than the first intensity threshold Th1.

When the first determination unit 54 determines that the intensity of the first detection signal DS1 is greater than or equal to the first intensity threshold Th1 (S102: Yes), the determination time is output to the second determination unit 56 as the start time ST. (S104).

After acquiring the start time ST, the second determination unit 56 acquires the second detection signal DS2 from the bandpass filter 42 (S106). The second determination unit 56 acquires the intensity of the potential of the second detection signal DS2 or the absolute value (that is, the magnitude) of the potential. The second determination unit 56 may acquire the second detection signal DS2 from the bandpass filter 42 via the first determination unit 54 together with the start time ST.

The second determination unit 56 acquires the second intensity threshold Th2 from the storage unit 52 and determines whether or not the intensity of the second detection signal DS2 is greater than or equal to the second intensity threshold Th2 (S108).

When the second determination unit 56 determines that the intensity of the second detection signal DS2 is not equal to or higher than the second intensity threshold Th2 (S108: No), the determination time JT is acquired from the storage unit 52 and the determination time JT is calculated from the start time ST. It is determined whether or not has passed (S110). When the second determination unit 56 determines that the determination time JT has not elapsed (S110: No), Step S106 and subsequent steps are repeated. That is, when the intensity of the second detection signal DS2 does not exceed the second intensity threshold Th2, the second determination unit 56 repeats steps S106 and S108 until the determination time JT has elapsed from the start time ST.

On the other hand, when the second determination unit 56 determines that the determination time JT has elapsed from the start time ST (S110: Yes), step S100 and subsequent steps are repeated. As described above, the fact that the intensity of the second detection signal DS2 does not exceed the second intensity threshold Th2 within the determination time JT means that the intensities of both the first detection signal DS1 and the second detection signal DS2 are large within the same time zone. It means that it did not happen. In this case, the second determination unit 56 determines that there is no partial discharge, and repeats Step S100 and subsequent steps.

Here, when the intensity of the second detection signal DS2 becomes equal to or higher than the second intensity threshold Th2 within the determination time JT from the start time ST, the intensity of both the first detection signal DS1 and the second detection signal DS2 is in the same time zone. It means that there is a partial discharge. In this case, the second determination unit 56 determines that the partial discharge is present by determining that the intensity of the second detection signal DS2 is equal to or higher than the second intensity threshold Th2 (S108: Yes), and indicates that the partial discharge is present. The determination result is transmitted to the output unit 46 (S112). After that, the output unit 46 outputs the determination result as an image or a sound.

As described above, in the partial discharge detection device 14, the first determination unit 54 and the second determination unit 56 include the first detection signal DS1 and the extraction frequency of the detection signal DS0 that are equal to or higher than the first frequency that increases due to the partial discharge. The presence of partial discharge is determined and detected based on the second detection signal DS2 of the band. In this way, the partial discharge detection device 14 removes signal components other than the first detection signal DS1 and the second detection signal DS2, which become noise in the detection of partial discharge, from the detection signal DS0, and determines the presence of partial discharge. Therefore, the detection accuracy of the partial discharge can be improved.

In the partial discharge detection device 14, the first determination unit 54 determines the start time ST based on the first detection signal DS1 having a higher frequency and less noise than the extraction frequency band, so that the determination of the start time ST is improved. As a result, the accuracy of the partial discharge determination can be improved.

<Second Embodiment>
FIG. 6 is a block diagram showing the function of the processing unit 134 of the partial discharge detection device 114 of the second embodiment. As shown in FIG. 6, the processing unit 134 of the partial discharge detection device 114 includes a high pass filter 40, a band pass filter 42, a peak detection unit 60, a control device 44, and an output unit 46.

The peak detection unit 60 reduces the peak of the high-frequency first detection signal DS1 transmitted by the high-pass filter 40 to a low frequency. For example, the peak detection unit 60 makes the peak of the first detection signal DS1 blunt so that the time width (eg, half-value width) of each peak having an intensity equal to or higher than the detection threshold is widened. The detection threshold value is smaller than the first intensity threshold value Th1, for example.

The control unit 50 of the control device 44 includes a first determination unit 54, a second determination unit 56, and a wavelet processing unit 62. The control unit 50 functions as the first determination unit 54, the second determination unit 56, and the wavelet processing unit 62 by reading the determination program stored in the storage unit 52, for example.

The first determination unit 54 compares the intensity of the first detection signal DS1 blunted by the peak detection unit 60 with the first intensity threshold Th1. The first determination unit 54 outputs the time at which the intensity of the first detection signal DS1 is equal to or higher than the first intensity threshold Th1 as the start time ST to the second determination unit 56.

The wavelet processing unit 62 executes the wavelet processing on the second detection signal DS2 containing noise or the like to reduce the noise in the extraction frequency band between the second frequency and the third frequency. To extract. In the present embodiment, the bandpass filter 42 and the wavelet processing unit 62 are examples of the second filter unit.

In the present embodiment, the bandpass filter 42 may be omitted. In this case, the wavelet processing unit 62 performs wavelet processing on the detection signal DS0 to extract the second detection signal DS2 in the extraction frequency band between the second frequency and the third frequency.

The wavelet processing unit 62 executes the wavelet processing based on the optimum wavelet analysis selected to extract the second detection signal DS2 with less noise from the wavelet database including a plurality of wavelet analyzes stored in advance in the storage unit 52. You may.

The wavelet processing unit 62 executes the wavelet processing between step S102 and step S106 in the flowchart of FIG. The wavelet processing unit 62 outputs the extracted second detection signal DS2 to the second determination unit 56.

The second determination unit 56 determines the presence of partial discharge based on the second detection signal DS2 on which the wavelet processing unit 62 has performed the wavelet processing.

In the partial discharge detection device 114 according to the second embodiment, the first determination unit 54 determines the start time ST based on the first detection signal DS1 blunted by the peak detection unit 60. Can be judged.

In the partial discharge detection device 114, since the wavelet processing unit 62 of the control unit 50 wavelet-processes the detection signal DS0 to generate the second detection signal DS2, the extraction frequency band of the second detection signal DS2 can be easily changed. Can handle. Further, since the wavelet processing unit 62 executes the wavelet processing on the second detection signal DS2 transmitted by the bandpass filter 42, the partial discharge detection device 114 can further reduce the noise of the second detection signal DS2.

<Third Embodiment>
FIG. 7 is an overall configuration diagram of an electric device system 210 including the partial discharge detection device 214 of the third embodiment. As illustrated in FIG. 7, the partial discharge detection device 214 according to the third embodiment includes a transmission unit 32, a signal acquisition unit 230, and a processing unit 34.

The transmission unit 32 includes an internal wiring 64 that is an example of a first wiring and is also called a core wire, an outer peripheral wiring 66 that is an example of a second wiring, and an insulating member 68. The internal wiring 64 and the peripheral wiring 66 include a conductive material such as copper. The internal wiring 64 and the outer peripheral wiring 66 electrically connect the signal acquisition unit 230 and the processing unit 34. As a result, the transmission unit 32 transmits the detection signal acquired by the signal acquisition unit 230 to the high pass filter 40 and the band pass filter 42. The outer peripheral wiring 66 is provided on the outer peripheral side of the internal wiring 64 so as to surround the internal wiring 64. The insulating member 68 includes an insulating material. The insulating member 68 is provided between the internal wiring 64 and the outer peripheral wiring 66 and on the outer peripheral side of the outer peripheral wiring 66. As a result, the insulating member 68 electrically insulates the internal wiring 64 and the peripheral wiring 66. The insulating member 68 provided on the outer peripheral side of the outer peripheral wiring 66 is also called a sheath.

The signal acquisition unit 230 includes a first electrode 70, a second electrode 72, a first connection wiring 74, and a second connection wiring 76.

The first electrode 70 and the second electrode 72 are configured in a flat shape. The first electrode 70 and the second electrode 72 include a conductive material.

The first electrode 70 is provided on the box body 20 via an insulating film 78 containing an insulating paint or the like. The first electrode 70 acquires the detection signal DS0. The smaller the relative permittivity of the insulating film 78, the better. The first electrode 70 is installed substantially parallel to one surface of the box body 20. The first electrode 70 is connected to the first connection wiring 74. As a result, the first electrode 70 is electrically connected to the internal wiring 64 of the transmission section 32 via the first connection wiring 74.

The second electrode 72 is arranged on the opposite side of the box body 20 with the first electrode 70 interposed therebetween. That is, the second electrode 72 is provided farther from the box body 20 than the first electrode 70. The second electrode 72 is arranged closer to the box body 20 than the end of the transmission section 32 on the box body 20 side. The second electrode 72 is arranged with a gap d from the first electrode 70. Air, an insulating material, or the like is interposed between the second electrode 72 and the first electrode 70. Therefore, the second electrode 72 is electrically insulated from the first electrode 70. The second electrode 72 is installed substantially parallel to the first electrode 70 and one surface of the box body 20. An opening 73 for passing the first connection wiring 74 is formed in the central portion of the second electrode 72. The second electrode 72 is connected to the second connection wiring 76. As a result, the second electrode 72 is electrically connected to the outer peripheral wiring 66 of the transmission section 32 via the second connection wiring 76. The second electrode 72 is electrically floating. The second electrode 72 may be connected to the ground potential such as the ground.

Next, an example of the distance d between the first electrode 70 and the second electrode 72 will be described. The distance d between the first electrode 70 and the second electrode 72 is preferably set so that the intensity V of the detection signal DS0 represented by the following equation (1) becomes maximum.
V=E×sin(2πd/λ) (1)
Incidentally, "E" in the equation (1) is the maximum value of the intensity V of the detection signal DS0. “Λ” is a wavelength corresponding to the frequency of either the first detection signal DS1 or the second detection signal DS2. The wavelength λ is more preferably a wavelength corresponding to the extraction frequency band of the second detection signal DS2 having low intensity. Therefore, it is preferable that the distance d satisfies the following expression (2). However, n is a positive integer.
d=(2n+1)λ/4 (2)

The larger the area of the area of the second electrode 72 facing the one surface of the box body 20, the larger the current can flow, and the larger the detection signal DS0 can be made. Therefore, it is preferable that the second electrode 72 has the same shape and the same area as the one surface of the box body 20 that faces the second electrode 72.

As described above, the signal acquisition unit 230 of the partial discharge detection device 214 has the second electrode 72 connected to the outer peripheral wiring 66 of the transmission unit 32 and facing the box body 20 and the first electrode 70. As a result, the first electrode 70 responds to the partial discharge by the electromotive force due to the linear electric field generated between the first electrode 70 and the second electrode 72, which is the potential based on the potential of the second electrode 72. It is acquired from the electric device 12 as the detection signal DS0. Accordingly, the signal acquisition unit 230 can stabilize the detection signal DS0 by reducing the fluctuation of the detection signal DS0 due to the influence of the charge amount of the partial discharge that changes depending on the length and arrangement of the transmission unit 32.

In the partial discharge detection device 214, a capacitance is formed between the first electrode 70 and one surface of the box body 20. As a result, the first electrode 70 acquires the change in the potential of the one surface of the box body 20 as the detection signal DS0. Here, since the partial discharge detection device 214 has the second electrode 72 facing the one surface of the box body 20, a current corresponding to the magnitude of the surface current flowing on the one surface of the box body 20 flows through the second electrode 72. As a result, the partial discharge detection device 214 can increase the detection signal DS0 acquired by the first electrode 70, and can relatively reduce noise. Further, since the area of the second electrode 72 is the same as the area of the one surface of the box body 20 facing the second electrode 72, it is possible to increase the detection signal DS0 while suppressing an increase in the size of the partial discharge detection device 214.

Further, in the partial discharge detection device 214, the detection signal DS0 can be made larger by disposing the position of the second electrode 72 at the position represented by the formula (2).

In the partial discharge detection device 214, the second electrode 72 is arranged closer to the box body 20 than the transmission section 32. As a result, the second electrode 72 can block the electromagnetic wave caused by the current flowing through the one surface of the box body 20, so that the influence of the electromagnetic wave that becomes noise on the transmission unit 32 can be reduced.

<Fourth Embodiment>
FIG. 8 is an overall configuration diagram of an electric device system 310 including the partial discharge detection device 314 of the fourth embodiment. As shown in FIG. 8, the partial discharge detection device 314 of the fourth embodiment includes a signal acquisition unit 330, a transmission unit 32, and a processing unit 34.

The signal acquisition unit 330 includes a first electrode 70, a second electrode 72, a first connection wiring 74, and a second connection wiring 376. The second connection wiring 376 has a folded portion 377. The folded-back portion 377 extends from the vicinity of the second electrode 72 to the vicinity of the first electrode 70, is folded back near the first electrode 70, and extends to the second electrode 72. As a result, the forward current and the backward current flowing through the turnback portion 377 of the second connection wiring 376 cancel each other out, so that electromagnetic noise can be reduced.

<Fifth Embodiment>
FIG. 9 is an overall configuration diagram of an electric device system 410 including the partial discharge detection device 414 of the fifth embodiment. As shown in FIG. 9, the partial discharge detection device 414 of the fifth embodiment includes a signal acquisition unit 430, a transmission unit 32, and a processing unit 34.

The signal acquisition unit 430 includes a first electrode 470, a second electrode 472, a first connection wiring 74, and a second connection wiring 76.

The first electrode 470 and the second electrode 472 are formed in a flat shape. The first electrode 470 and the second electrode 472 are arranged substantially parallel to one surface of the box body 20.

The second electrode 472 is provided on the box body 20 via an insulating film 78 containing an insulating paint or the like. The first electrode 470 is arranged on the opposite side of the box body 20 with the second electrode 472 interposed therebetween. That is, the second electrode 472 is provided closer to the box body 20 than the first electrode 470.

In the partial discharge detection device 414, since the second electrode 472 is provided on the box body 20, the potential of the second electrode 472 and the box body 20 can be made substantially equal to each other in a high frequency signal. Thereby, in the partial discharge detection device 414, the noise of the detection signal DS0 acquired by the first electrode 470 can be reduced and the detection signal DS0 can be stabilized.

The embodiments described above may be modified as appropriate. Moreover, you may combine each embodiment suitably.

Although the above-described third to fifth embodiments have been described by taking the configuration having the processing unit 34 as an example, the processing units having other configurations may be provided. For example, the third to fifth embodiments may include a processing unit such as the processing unit 134 that can determine the presence of another partial discharge. The other processing unit includes any one of the high pass filter 40, the band pass filter 42, and the wavelet processing unit 62, and any one of them may be omitted.

In the above-described embodiment, the box body 20 is given as an example of the storage member, but the storage member is not limited to this. For example, the housing member may be made of an insulating material in which the electric device 22 is molded. In this case, the signal acquisition units 30, 230, 330, 430 are provided in the insulating material of the mold.

In the above-described embodiment, the first determination unit 54 and the second determination unit 56, once determining that partial discharge exists, output a determination result to that effect, but the present invention is not limited to this. For example, when the first determination unit 54 and the second determination unit 56 determine multiple times that partial discharge exists, the determination result indicating that partial discharge exists may be output. Further, when the first determination unit 54 and the second determination unit 56 determine that the partial discharges are present multiple times for each predetermined determination cycle, even if the determination result indicating that the partial discharge is present is output. Good. An example of the determination cycle is twice the cycle of the AC power supplied from the power source 90 to the electric device 22. The value of this determination cycle is based on the fact that partial discharge occurs at a cycle twice as long as the AC power.

Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and the scope of equivalents thereof.

In order to solve the above-described problems and achieve the object, the partial discharge detection device of the embodiment includes a signal acquisition unit, a first filter unit, a second filter unit, and a determination unit. The signal acquisition unit is provided in a housing member that houses an electric device and acquires a detection signal. The first filter unit extracts a first detection signal having a frequency equal to or higher than a first frequency , which is included in the detection signal and is defined as a partial discharge originating from an electromagnetic wave, and allows the first detection signal to pass therethrough. A detection signal of a frequency lower than the first frequency is cut off . The second filter unit is included in the detection signal and has a frequency band lower than the first frequency and is defined as a second frequency and a third frequency which are determined as derived from a ground current flowing to a ground potential by partial discharge. The second detection signal in the extraction frequency band, which is the frequency band between and , is extracted and passed, and the detection signals other than the extraction frequency band included in the detection signal are blocked . The determination unit determines the presence of partial discharge based on the first detection signal that has passed through the first filter unit and the second detection signal that has passed through the second filter unit .

Claims (7)

A signal acquisition unit that is provided in a housing member that houses an electric device and acquires a detection signal,
A first filter unit for extracting a first detection signal having a frequency higher than a first frequency included in the detection signal;
A second filter unit for extracting a second detection signal in a frequency band between a second frequency and a third frequency included in the detection signal;
A determination unit that determines the presence of partial discharge based on the first detection signal and the second detection signal;
And a partial discharge detection device. The determination unit,
The first detection is performed during a predetermined determination time from a start time, which is a time when the intensity of one of the first detection signal and the second detection signal is equal to or greater than a predetermined first intensity threshold. The partial discharge detection device according to claim 1, wherein when the other intensity of the signal and the second detection signal is equal to or higher than a predetermined second intensity threshold, it is determined that the partial discharge exists. The determination unit,
When the intensity of the second detection signal is equal to or higher than the second intensity threshold during the determination time from the start time when the intensity of the first detection signal is equal to or higher than the first intensity threshold, the partial discharge is performed. The partial discharge detection device according to claim 2, wherein the partial discharge detection device is determined to exist. Further comprising a transmission unit having a first wiring and a second wiring for transmitting the detection signal acquired by the signal acquisition unit to the first filter unit and the second filter unit,
The signal acquisition unit,
A planar first electrode that is connected to the first wiring and acquires the detection signal;
A planar second electrode that is connected to the second wiring and faces the first electrode;
The partial discharge detection device according to claim 1, further comprising: A signal acquisition unit that is provided in a housing member that houses an electric device and acquires a detection signal,
A transmission unit having a first wiring and a second wiring for transmitting the detection signal acquired by the signal acquisition unit;
Based on the detection signal transmitted by the transmission unit, a determination unit that determines the presence of partial discharge,
Equipped with
The signal acquisition unit,
A planar first electrode that is connected to the first wiring and acquires the detection signal;
A planar second electrode facing the first electrode connected to the second wiring;
Partial discharge detection device having. The partial discharge detection device according to claim 5, wherein the second electrode is provided farther from the housing member than the first electrode. The partial discharge detection device according to claim 5, wherein the second electrode is provided closer to the housing member than the first electrode.

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