JPH10341520A - Partial discharge detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect partial discharge economically and with high sensitiveness, by signal-processing the electromagnetic waves leaking out of the insulator in a container which accommodates a high-voltage electric apparatus in high insulative condition with a certain band width in a microwave region. SOLUTION: When partial discharge occurs inside a gas insulating switchgear 1, the electromagnetic waves by microwaves of tens of MHz to tens of GHz by partial discharge are propagated into inside of containers 2 and 3, etc. These electromagnetic waves leak through the cut of the cover 13 from the insulating spacer 4 caught by the flanges 2a and 3a of the containers 2 and 3. These leaked electromagnetic waves are led by a guide 12, and are received with the antenna 8 for microwaves of a microwave sensor 7, and are signal-processed by a signal processor 9. The processed received signal is sent to a signal processing judging unit 11, passing through a coaxial cable 10, and the existence of partial discharge, the size, etc., are judged from the signal level, etc., and the partial discharge detection is performed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a partial discharge detecting device for detecting a partial discharge in a high-voltage electric device such as a gas insulated switchgear by receiving an electromagnetic wave generated by the partial discharge.

[0002]

2. Description of the Related Art FIG. 5 is a block diagram of a conventional partial discharge detecting device of a gas insulated switchgear disclosed in Japanese Patent Application Laid-Open No. 3-139110. In the figure, reference numeral 26 denotes a part of the gas insulated switchgear. The containers 27a and 27b constituting the gas insulated switchgear 26 are connected by an assembly bolt and nut 31 at flanges 27d and 27e with an insulating spacer 28 supporting a conductor 27c interposed between the containers 27a and 27b. Incidentally, each nut of the assembly bolt nut 31 and the flange portions 27d, 27e are insulated washer 31a, 31b.
Insulated by

[0005] Inside the insulating spacer 28, an electric field alleviating electrode / antenna 29, a connection bolt 30 for supporting the antenna surface of the electric field alleviating electrode / antenna 29 in parallel to the conductor 27 c, and an embedded bolt for fixing the connection bolt 30. Gold 28a is buried. The containers 27a and 27b are connected to the flange 27.
The bolts of the assembly bolt nut 31 connected by d and 27e penetrate through the opening of the filling metal 28a to make electrical contact.

[0004] Further, the assembled bolt / nut 31 is provided with a low-pass filter 32 for preventing intrusion of noise of low frequency components.
And a receiver 34 is connected via a coaxial cable 33. The output side of the receiver 34 is connected to a signal processing determination unit 35 for processing a received signal. These electric field alleviating electrode / antenna 29, low-pass filter 32, receiver 34, and signal processing determination unit 35 constitute a partial discharge detection device.

Next, the operation of the conventional partial discharge detecting device will be described. When an electromagnetic wave generated due to the partial discharge of the gas insulated switchgear 26 propagates inside the containers 27a and 27b, the electric field reducing electrode and antenna 2 in the insulating spacer 28
9 is received. Received radio waves are connection bolts 30 and gold 28
a, it is input to the receiver 34 via the assembly bolt nut 31 and the coaxial cable 33. Then, the received signal is sent to the signal processing determination unit 35, and the occurrence of partial discharge is detected and determined from the signal level and the like.

[0006]

As described above, in the conventional partial discharge detecting device, since the electromagnetic wave shield is not applied to the insulating spacer portion, it is generated outside the gas insulated switchgear and propagates through the container 27. Since a progressive high-frequency oscillating potential is also detected, the possibility of erroneous detection of partial discharge is high.In addition, external noise mixed into electromagnetic waves due to partial discharge cannot be reduced and partial discharge detection can be performed with high accuracy. There was a problem that it could not be performed.

Since the reception of the electromagnetic wave by the electric field alleviating electrode / antenna 29 mainly depends on the electrostatic coupling between the conductor 27c and the burying metal 28a, a high voltage electric wave separated from the place where the partial discharge detecting device is installed is provided. There is a problem that it is difficult to receive an electromagnetic wave due to a partial discharge generated in a device even if it travels through the insulating gas space, and it is not possible to detect the partial discharge with high accuracy.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and has as its object to provide a partial discharge detection device which can detect a partial discharge economically and with high sensitivity.

[0009]

According to a first aspect of the present invention, there is provided a partial discharge detecting apparatus for receiving an electromagnetic wave leaking from an insulator in a container for accommodating a high-voltage electric device while maintaining insulation, and a receiver for receiving the electromagnetic wave. Signal processing means for performing signal processing on electromagnetic waves received by the means with a constant bandwidth in the microwave region,
Signal processing determining means for determining reception of an electromagnetic wave due to partial discharge from the high-voltage electrical device based on a value of the processing signal, and detecting partial discharge inside the high-voltage electrical device.

In the partial discharge detection device according to the second aspect of the present invention, an opening is formed at a depth from the outside of the container to the inside insulator to expose the insulator, and leak from the exposed insulator. The electromagnetic wave is received by the receiving means.

According to a third aspect of the present invention, there is provided a partial discharge detection device, wherein an opening is formed at a predetermined position of a container, and the opening is covered with an insulating material so as to maintain a sealed state in the container. The electromagnetic wave leaking from the insulator is received by the receiving means.

According to a fourth aspect of the present invention, there is provided a partial discharge detecting device, wherein a guide member for blocking electromagnetic waves from the outside and guiding the leakage electromagnetic wave from the insulator to the receiving surface of the receiving means extends from the exposed insulator to the receiving means. It is formed.

The guide member in the partial discharge detection device according to the fifth aspect of the present invention includes the receiving means and is detachably provided on the exposed portion of the insulator.

The signal processing means in the partial discharge detecting device according to the invention of claim 6 converts the processed signal into an optical signal and outputs the signal through an optical fiber to a signal processing determining means provided with a photoelectric conversion means.

According to a seventh aspect of the present invention, the signal processing means in the partial discharge detection device includes a band-pass filter and processes an electromagnetic wave signal having a constant bandwidth in a microwave range of 1 GHz to 10 GHz in a received electromagnetic wave. .

[0016]

DETAILED DESCRIPTION OF THE INVENTION

Embodiment 1 FIG. Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a configuration diagram of a partial discharge detection device according to the present embodiment. In the figure, reference numeral 1 denotes a part of a gas-insulated switchgear to which the present embodiment is applied. Containers 2 and 3 constituting this gas insulated switchgear 1 are provided with insulating spacers 4 for supporting conductors 5 in the containers 2 and 3 with flange portions 2a and 2a.
3a, and are connected to the flanges 2a, 3a through unillustrated assembly bolts and nuts. Flange 2a,
A cover 13 made of an electromagnetic wave shielding material that blocks electromagnetic waves from the outside is wound around the outer peripheral surface of the insulating spacer 4 sandwiched between 3a, and a part of the cover 13 is cut away to expose the insulating spacer 4. .

A hollow cylindrical guide 12 made of the same electromagnetic wave shielding material as the cover 13 is erected around the notch to expose microwaves caused by partial discharge inside the gas insulated switchgear 1. It is led from the insulating spacer 4 to the outside. In the other opening of the guide 12, a microwave sensor 8 containing a microwave antenna 8 as a receiving means and a signal processing unit 9 as a signal processing means for processing the microwave received by the microwave antenna 8 Is installed.
The signal processing unit 9 is connected via a coaxial cable 10 to a signal processing determination unit 11 as signal processing determination means.
The signal processing unit 9 includes a band-pass filter, an amplification unit, a detection unit, and the like.

Next, the operation of the present embodiment will be described. When a partial discharge occurs inside the gas insulated switchgear 1, several tens of MHz due to the partial discharge occur inside the containers 2 and 3 and the like.
Electromagnetic waves of microwaves of several to several tens Ghz are propagated. This electromagnetic wave leaks from the insulating spacer 4 sandwiched between the flanges 2 a and 3 a of the containers 2 and 3 through the notch of the cover 13.

The leaked electromagnetic wave is guided to the guide 12, received by the microwave antenna 8 of the microwave sensor 7, and processed by the signal processing unit 9. The processed reception signal passes through a coaxial cable 10 and is processed by a signal processing determination unit 1.
1, the presence or absence or magnitude of partial discharge is determined from the signal level or the like, and partial discharge detection is performed.

The reception sensitivity of the signal processing unit 9 is maximized by arranging the reception surface of the microwave antenna 8 of the microwave sensor 7 substantially parallel to the outer peripheral surface of the insulating spacer 4. When the shape of the insulating spacer 4 is disk-shaped, the sensitivity may differ depending on the position of the antenna surface with respect to the outer circumferential surface. In this case, it is preferable to perform electromagnetic wave reception at a position having the highest reception sensitivity.

In the present embodiment, the guide 12 and the cover 13 prevent external electromagnetic waves from entering the microwave sensor 7, thereby increasing the reception sensitivity of electromagnetic waves due to partial discharge. However, when it is not necessary to increase the receiving sensitivity, the guide 12 or the cover 13 or both need not be used.

Of the above electromagnetic waves, 1 GHz to 10 G
Since the microwave in the frequency band of Hz is hard to enter the inside of the containers 2 and 3 from the outside, the reception signal by the electromagnetic wave generated by the partial discharge inside the container is hardly affected by the external noise. Further, the microwave sensor 7 has a band-pass filter, receives microwaves in a frequency band of 1 GHz to 10 GHz, and raises the S / N ratio so as to avoid electromagnetic waves in a frequency band other than noise. The required electromagnetic wave reception sensitivity can be extremely increased.

As described above, in this embodiment, in order to detect the partial discharge by receiving the electromagnetic wave leaking from the surface of the insulator exposed to the outside of the gas insulated switchgear 1, the antenna is provided as in the prior art. It is not necessary to add special processing to the inside of the insulating spacer. Therefore, the device can be constructed economically. The insulator exposed to the outside of the gas insulated switchgear 1 is, in addition to the insulating spacer, the insulator of the ground switch, the insulator of the ground terminal, the connection portion with the power cable, the viewing window for the switchgear, and other devices. The same effect can be obtained by providing the partial discharge detection device with the above-described configuration on these insulators.

The gas-insulated switchgear 1 is shown as an example of a high-voltage electric device to which the present embodiment is applied. In addition, a gas-insulated bus, a transformer, a reactor, a transformer, a circuit breaker, a circuit breaker, a switch, a lightning arrestor, and a capacitor are provided. The present invention can be similarly applied to a high-voltage electric device which is housed in another hermetically sealed container such as a generator, a motor, a high-voltage semiconductor conversion device, a power cable, a power cable connection portion while maintaining insulation. Further, the partial discharge detection device can be constantly attached to the detection target device for continuous monitoring, or it can be portable and attached when necessary to monitor the partial discharge.

Embodiment 2 Another embodiment of the present invention will be described with reference to the drawings. In FIG. 2, reference numeral 14 denotes an insulating spacer in which a metal flange 15 is wound around the outer peripheral surface of a spacer made of an insulating material. In the circumferential surface of the metal flange 15 of the insulating spacer 14, an opening 16 having a depth reaching the insulating material is formed at a portion where the guide 12 is connected.

A screw groove is formed on the inner peripheral surface of the opening 16 and is usually closed through a metal screw. When a partial discharge is detected, the metal screw is removed, and a screw is formed on the outer peripheral surface at the tip of the opening 12 a of the guide 12. The guide 12 is screwed to the metal flange 15 by aligning the groove with the screw groove of the opening 16.

The other opening of the guide 12 is connected to the microwave sensor 7 to which the signal processing judging unit 11 is connected by the coaxial cable 10 as in the first embodiment.

Next, the operation of this embodiment will be described. The opening 16 of the metal flange 15 is normally closed by tightening a metal screw. When the guide 12 is screwed to the metal flange 15 to detect partial discharge, the metal screw is removed and the opening of the guide 12 is removed. The threaded portion 12 a is screwed in accordance with the thread groove of the opening 16.

When a partial discharge occurs in the gas insulated switchgear 1, an electromagnetic wave composed of microwaves of several tens of MHz to several tens of Ghz is generated by the partial discharge in the containers 2 and 3 and the like. Unlike the first embodiment, this electromagnetic wave is electromagnetically shielded by the metal flange 15 at the position of the insulating spacer 14 and does not leak to the outside of the containers 2 and 3. However, since the opening 16 having a depth reaching the insulating spacer 14 is provided in the portion where the microwave sensor 7 is attached to the metal flange 15, the microwave sensor is provided in the opening 16 via the guide 12 made of an electromagnetic shielding material. 7 and the first embodiment
Similarly, the electromagnetic wave leaked from the insulator of the insulating spacer 14 to the opening 16 through the guide 12
And received by the microwave antenna 8.

FIG. 2 shows an example of the insulating spacer 14 of the conductor 5 as an insulator for leaking electromagnetic waves to the outside. However, in a sealed container accommodating a high-voltage electric device, the high-voltage electric device and the closed container are connected. This embodiment can be applied to any insulator having a function of maintaining insulation between the electrodes.

In this embodiment, a method has been described in which electromagnetic waves leaking from the insulating spacer supporting the conductor are received through the insulating spacer. However, an insulating material is adhered to the inner surface of the metal container housing the high-voltage electrical equipment. Even in the case where the opening is formed to a depth from the outside of the metal container to the insulator as in the present embodiment, a screw groove is cut in the inner peripheral surface of the opening, and usually the metal is formed in the opening. A screw is fitted and a metal cover is inserted. At the time of partial discharge detection, the threaded portion of the opening of the guide 12 is inserted into a screw groove, and the microwave sensor 7 is screwed. Electromagnetic waves leaking from the insulator are directly transmitted from the insulator. You may receive it.

Embodiment 3 FIG. In the first and second embodiments, the partial discharge is detected by receiving the electromagnetic waves leaking from the insulating spacers 4 and 14 supporting the conductor 5, but the flanges 2a and 3a of the containers 2 and 3 sandwiching the insulating spacers 4 and 14 are detected. May not be in a position suitable for attaching the microwave sensor 7. Therefore, in the present embodiment, as shown in FIG. 3, for example, in the container 2, an opening 17 is formed at a position suitable for attaching the microwave sensor 7, and a cylindrical body 17b having a flange 17a formed around the opening 17 is formed. Is fixed.

On the flange 17a, a circular insulating plate 18 having a diameter slightly smaller than the diameter of the flange 17a and having a thread groove formed on the outer peripheral surface is attached, and the opening 17 is covered. Keeps hermetically sealed. On the other hand, the microwave sensor 7 in the present embodiment is housed in a cylindrical metal box 20 and shielded from electromagnetic waves in order to prevent noise from entering from outside. In addition, an insulating plate 1 is provided at the end of the opening of the metal box 20.
A metal flange 20a having the same thickness as 8 and having a thread groove similar to the thread groove of the insulating plate 18 is provided on the inner peripheral surface.
At the bottom of the metal box 20, a conduit 21 for drawing the coaxial cable 10 to the outside is formed.

Next, the operation of this embodiment will be described. Since the opening 17 of the container 2 is covered with the insulating plate 18, the sealing property of the insulating gas in the container 2 is maintained. When the microwave sensor 7 is coupled to the container 2 to detect the partial discharge, the screw groove of the metal flange 20a formed on the metal box 20 is aligned with the screw groove of the insulating plate 18, and the flange 20a is Screw it in until it comes into contact with the flange 17a of the cylindrical body 17b formed around the side opening 17. As a result, the metal box 20 is screwed to the container 2 via the flange 19, and serves as an electromagnetic wave shield that shields the microwave sensor 7 from external electromagnetic waves.

Next, when a partial discharge occurs inside the gas insulated switchgear 1, microwaves of several tens of MHz to several tens of Ghz due to the partial discharge are generated inside the containers 2 and 3 and the like. This electromagnetic wave leaks from the insulating plate 18 attached to the opening 17 provided in the container 2 to the microwave sensor 7 unlike the first and second embodiments. At this time, since the metal box 20 is screwed to the insulating plate 18 via the flange 19, the electromagnetic wave leaking from the insulating plate 18 is guided to the metal box 20 by the microwave sensor 7 stored therein. The partial discharge is detected by being received by the antenna 8.

In FIG. 3, the insulating medium inside the container 2 may be any medium such as gas, insulating oil, mixed gas, and solid. The material of the insulating plate 18 may be an organic insulating material or an inorganic insulating material as long as the material transmits electromagnetic waves.

Embodiment 4 FIG. In the first to third embodiments, the signal processed by the signal processing unit 9 is transmitted to the signal processing determination unit 25 through a coaxial cable by an electric signal.
When the signal processing determination unit 25 is installed at a long distance, noise tends to be included in the transmission signal.

Therefore, in this embodiment, the influence of noise is reduced by converting the signal from the signal processing unit 9 to the signal processing determination unit 25 into an optical signal and transmitting it. FIG. 4 is a configuration diagram of the partial discharge detection device 22 according to the present embodiment. In the drawing, the same reference numerals as those in FIG. 1 indicate the same or corresponding parts. In the figure, reference numeral 23 denotes an electro-optical signal conversion device that converts a signal output from the signal processing unit 9 into an optical signal, and reference numeral 24 denotes an optical cable that transmits an optical signal to the signal processing determination unit 25a.

Next, the operation of this embodiment will be described. When a partial discharge occurs inside the gas insulated switchgear 1, several tens of MHz due to the partial discharge occur inside the containers 2 and 3 and the like.
A microwave electromagnetic wave of 10 to several tens Ghz is generated. This electromagnetic wave leaks outside from between the flanges 2a and 2b of the containers 2 and 3 sandwiching the insulating spacer 4.

The leaked electromagnetic wave is guided to the guide 12,
After being received by the antenna 8 of the microwave sensor 7 and subjected to signal processing by the signal processing unit 9, the electro-optical signal conversion device 2
The signal is converted into an optical signal in 3. This optical signal is transmitted through the optical cable 24
The signal is transmitted to the signal processing determination unit 25a through an optical signal conversion device (not shown), and after being converted into an electric signal, the presence or absence or magnitude of partial discharge is determined based on the level of the electric signal, and partial discharge detection is performed. . According to the present embodiment, since an optical fiber, an optical signal processing device, and the like are used, a processed signal can be transmitted over long distances without being affected by external noise.

[0041]

According to the first aspect of the present invention, there is provided a receiving means for receiving electromagnetic waves leaking from an insulator in a container for storing high-voltage electrical equipment while maintaining insulation, and a microwave receiving means for receiving the electromagnetic waves received by the receiving means. A signal processing unit that performs signal processing with a constant bandwidth of a region, and determines reception of electromagnetic waves caused by partial discharge from the high-voltage electric device based on a value of the processed signal, and detects partial discharge inside the high-voltage electric device Since the signal processing determination means is provided, there is an effect that the partial discharge of the high-voltage electrical equipment can be detected with high sensitivity at a low cost while eliminating the influence of external noise components.

According to the second aspect of the present invention, the opening is formed at a depth from the outside of the container to the inside of the container to expose the insulating material, and the electromagnetic wave leaking from the exposed insulating material is received. In this case, the partial discharge can be detected at a location most suitable for detecting the partial discharge.

According to the third aspect of the present invention, an opening is formed at a predetermined position of the container, and the opening is covered with an insulating material so as to keep the inside of the container tightly sealed, and leakage from the insulating material is prevented. Receiving the received electromagnetic wave by the receiving means has an effect that the partial discharge can be detected at a location most suitable for detecting the partial discharge while maintaining the sealed state in the container.

According to the fourth aspect of the present invention, since the guide member for blocking the electromagnetic waves from the outside and guiding the leakage electromagnetic waves from the insulator to the receiving surface of the receiving means is formed from the exposed insulator to the receiving means, There is an effect that partial discharge can be detected with high quality by eliminating the influence of noise.

According to the fifth aspect of the present invention, since the guide member includes the receiving means and is detachably provided on the exposed portion of the insulator, the portability of the device can be realized.

According to the sixth aspect of the present invention, the signal processing means converts the processed signal into an optical signal and then outputs the processed signal to the signal processing determining means provided with the photoelectric conversion means through an optical fiber, thereby speeding up the processed signal. In addition, there is an effect that long-distance transmission can be performed while eliminating the influence of noise.

According to the seventh aspect of the present invention, the signal processing means is provided with a band-pass filter, and receives a 1 GHz
By processing an electromagnetic wave signal having a constant bandwidth in a microwave range of 10 GHz to 10 GHz, partial discharge can be detected with high sensitivity and economically.

[Brief description of the drawings]

FIG. 1 is a sectional view of a gas-insulated switchgear to which a partial discharge detection device according to an embodiment of the present invention is attached.

FIG. 2 is a cross-sectional view of a gas-insulated switchgear to which a partial discharge detection device according to another embodiment of the present invention is attached.

FIG. 3 is a sectional view of a gas-insulated switchgear to which a partial discharge detection device according to another embodiment of the present invention is attached.

FIG. 4 is a sectional view of a gas insulated switchgear to which a partial discharge detection device according to another embodiment of the present invention is attached.

FIG. 5 is a cross-sectional view of a gas-insulated switchgear equipped with a partial discharge detection device according to a conventional embodiment.

[Explanation of symbols]

1 Gas insulated switchgear, 2, 3 containers, 2a, 3a flanges, 4 insulating spacers, 5 conductors, 6, 22 partial discharge detection device, 7 microwave sensor, 8 antenna,
9 signal processing unit, 10 coaxial cable, 11 signal processing determination unit, 12 guide, 13 cover, 14 insulating spacer, 15 metal unit, 16, 17 opening, 18 insulating plate, 19 mounting plate (flange), 20 metal box, 23
Electro-optical signal converter, 24 optical fiber, 25, 25a
Signal processing determination unit.

Claims (7)

[Claims] 1. A receiving means for receiving an electromagnetic wave leaking from an insulator in a container for housing a high-voltage electric device while maintaining insulation, and a signal processing means for processing the electromagnetic wave received by the receiving means with a constant bandwidth in a microwave region. Signal processing means, and signal processing determining means for determining reception of electromagnetic waves due to partial discharge from the high-voltage electrical device from the value of the processing signal, and detecting partial discharge inside the high-voltage electrical device. A partial discharge detection device characterized by the above-mentioned. 2. The method according to claim 1, wherein an opening is formed at a depth from the outside of the container to the inner insulator to expose the insulator, and electromagnetic waves leaking from the exposed insulator are received by the receiving means. The partial discharge detection device according to claim 1. 3. An opening is formed in a predetermined position of the container, and the opening is covered with an insulator so as to keep the inside of the container tightly closed, and the receiving means receives electromagnetic waves leaking from the insulator. 2. The partial discharge detection device according to claim 1, wherein: 4. A guide member, which intercepts an external electromagnetic wave and guides a leaked electromagnetic wave from an insulator to a receiving surface of the receiving means, is formed from the exposed insulator to the receiving means. 4. The partial discharge detection device according to any one of claims 3 to 3. 5. The partial discharge detecting device according to claim 4, wherein the guide member includes a receiving means and is detachably provided on an exposed portion of the insulator. 6. The signal processing means according to claim 1, wherein said signal processing means converts the processing signal into an optical signal and outputs the signal through an optical fiber to a signal processing determining means provided with a photoelectric conversion means.
6. The partial discharge detection device according to any one of claims 5 to 5. 7. The signal processing means according to claim 1, further comprising a band-pass filter for processing an electromagnetic wave signal having a constant bandwidth in a microwave range of 1 GHz to 10 GHz in a received electromagnetic wave. 2. The partial discharge detection device according to claim 1.