JPH09243701A - Method of diagnosing electric equipment insulation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To set an external antenna without being accompanied by service interrupting work or dangerous work in an electric equipment insulation diagnostic device for detecting an electromagnetic wave by partial discharge by use of the external antenna. SOLUTION: When a partial discharge is generated within the vessel 2 of an electric equipment 1, an electromagnetic wave by the partial discharge is emitted from a bushing 3. The plane of polarization of this electromagnetic wave is conformed to the longitudinal direction of the conductor 4 of the bushing 3. The plane of polarization of the partial discharge detecting antenna 5 of an insulating diagnostic device is conformed to the longitudinal direction of the conductor 4 to efficiently detect the electromagnetic wave by the partial discharge. A noise detecting antenna 6 is set so that its plane of polarization is orthogonal to the longitudinal direction of the conductor to detect only noise. A judgment device 9 judges whether the partial discharge is generated within the electric equipment on the basis of the difference between the signals detected by both the antennas. Since it is not required to directly mount these antennas on the bushing part, the necessity of a service interrupting work or dangerous work is eliminated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for diagnosing insulation performance of electric equipment, and more particularly to diagnosing insulation performance of electric equipment by detecting a partial discharge generated inside the electric equipment by an external antenna. Regarding the device.

[0002]

2. Description of the Related Art It is known that in electrical equipment such as a gas insulated switchgear, a gas circuit breaker, and a cubicle, if the insulation performance deteriorates for some reason, partial discharge occurs as a precursory phenomenon before an arc flash accident. ing. The insulation diagnostic device detects this partial discharge at a minor stage, thereby preventing an arc flash accident. As a method of detecting this partial discharge, an antenna is placed outside the electrical equipment,
There is a method of detecting electromagnetic waves generated by partial discharge.

When the electric device is covered with a metal container such as the above-described gas-insulated switchgear, gas circuit breaker, and cubicle, the metal container has a high shielding effect against electromagnetic waves. In such an electric device, the insulating spacer or the bushing portion serves as an opening for electromagnetic waves generated by partial discharge. Conventionally, when an antenna for detecting an electromagnetic wave by partial discharge is attached to the outside of an electric device, the antenna for detecting partial discharge is attached to an insulating spacer or a bushing portion which becomes an opening.

In addition, in order to remove the influence of noise from the detection signal of the antenna for detecting partial discharge when detecting partial discharge, an antenna for receiving ambient noise is provided in a portion that does not become the opening of the electric equipment container. There is. In this case, the difference between the detection signal of the partial discharge detection antenna and the detection signal of the ambient noise reception antenna is taken to remove the influence of noise from the detection signal of the partial discharge detection antenna.

[0005]

In the above-described conventional antenna mounting method, since the antenna is directly mounted on the electric equipment, the bushing portion is often located at a high place or a complicated place, so that workability at the site is poor. . To install the antenna on the bushing part, power outage work is required. Further, there is a problem that dangerous work is involved when the power outage work is not performed. Furthermore, in order to remove the influence of noise, a noise detection antenna is required in addition to the partial discharge detection antenna.

An object of the present invention is to enable installation of an antenna in an electrical equipment insulation diagnostic device that detects an electromagnetic wave due to partial discharge using an external antenna, without blackout work or dangerous work. To do.

[0007]

SUMMARY OF THE INVENTION The present invention has been made to achieve the above object. The electrical equipment insulation diagnosis device of the present invention detects an electromagnetic wave generated by a partial discharge generated inside an electrical equipment having a bushing for pulling out a high-voltage conductor by an antenna arranged outside the electrical equipment.

When a partial discharge is generated inside the electric device, the electromagnetic waves generated by the partial discharge are radiated to the outside through the bushing portion. In this case, the plane of polarization of the electromagnetic wave is radiated mainly in the length direction of the bushing. In contrast,
An antenna for detecting electromagnetic waves due to partial discharge has a gain with respect to one-direction polarized light, and its polarization plane is arranged along the length direction of the bushing.

Therefore, since the partial discharge detecting antenna efficiently detects the electromagnetic waves due to the partial discharge generated inside the electric equipment, it is not necessary to directly attach it to the electric equipment. This eliminates the need for power outage work when attaching the antenna, and eliminates dangerous work. The signal detected by this antenna is input to the determination device, and the determination device determines, based on this signal, whether or not partial discharge has occurred inside the electric device by a known method.

Further, in the present invention, when the noise detecting antenna is used together to remove the influence of noise, the polarization plane of the noise detecting antenna is arranged so as to be perpendicular to the length direction of the bushing. As a result, the noise detecting antenna does not detect the electromagnetic waves due to the partial discharge but mainly detects only the ambient noise. Then, the detection signal of the partial discharge detection antenna and the detection signal of the noise detection antenna are input to the determination device. The determination device determines, based on the difference between the detection signals of both antennas, whether or not partial discharge has occurred inside the electric device by a known method.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. In each figure, components having the same function are designated by the same reference numeral, and overlapping description will be omitted. (Embodiment 1) FIG. 1 shows a basic configuration of the present invention.

In the figure, reference numeral 1 is an electric device, and a bushing 3 is provided on a container 2. When the partial discharge 10 occurs in the container 2 due to the insulation abnormality, the electromagnetic wave generated by the partial discharge 10 is radiated to the outside from the conductor 4 in the bushing 3. At this time, the plane of polarization of the electromagnetic waves coincides with the length direction of the conductor 4. 5 is an antenna for detecting partial discharge, 6
Is a noise detection antenna. As these antennas, antennas having a gain in one polarization direction are used. Examples of the antenna having a gain in one polarization direction include a Yagi antenna, a dipole antenna, a folded dipole antenna, and the like. In this example, the Yagi antenna is used. The partial discharge detection antenna 5 and the noise detection antenna 6 can be shared by one antenna. In this case, the antenna is rotated 90 ° before use.

The partial discharge detecting antenna 5 is arranged such that its plane of polarization is aligned with the plane of polarization of electromagnetic waves due to partial discharge, that is, the length direction of the bushing. In the figure, the antenna elements are arranged vertically. By thus matching the polarization plane of the electromagnetic wave with the polarization plane of the antenna 5, the electromagnetic wave can be efficiently detected without directly attaching the antenna to the electric device 1, and the occurrence of partial discharge can be detected. The partial discharge detection antenna 5 detects not only electromagnetic waves due to partial discharge but also ambient noise.

The polarization plane of the noise detecting antenna 6 is arranged perpendicularly to the polarization plane of the electromagnetic waves generated by the partial discharge, that is, perpendicular to the length direction of the bushing. In the figure, the antenna elements are arranged horizontally. With this arrangement, the noise detection antenna 6 mainly detects only noise because the gain for electromagnetic waves due to partial discharge is reduced.

The outputs of the antennas 5 and 6 are input to the judging device 9 through separate coaxial cables 7 and 8, respectively. Since the configuration and operation of the determination device 9 are known, detailed description thereof will be simplified here. Antenna 5,6
Is output to the change-over switch 91, the detection signal of one of the antennas is selected and input to the amplifier 92. From the signal amplified by the amplifier 92, the tuner 93 extracts signals of a plurality of predetermined frequencies. This signal passes through the detector 94, is converted into a digital signal by the A / D converter 95, and is input to the CPU 96.

The CPU 96 removes the influence of noise by taking the difference between the signal detected by the partial discharge detection antenna 5 and the signal detected by the noise detection antenna 6, and then determines whether or not partial discharge occurs based on the acquired spectrum. To judge. In the illustrated example, the partial discharge detection antenna 5 and the noise detection antenna 6 are provided, but the noise detection antenna 6 may be omitted and the partial discharge detection antenna 5 alone may be used for diagnosis.

Further, in this example, the noise can be detected by directing the noise detecting antenna 6 in a direction different from that of the electrical equipment to be diagnosed. (Embodiment 2) FIG. 2 shows an example of diagnosing insulation performance for each phase in a three-phase tank type gas circuit breaker.

In FIG. 2, reference numeral 11 is a three-phase tank type gas circuit breaker, and the U-phase, V-phase and W-phase circuit breakers are housed in independent containers 21, 22 and 23, respectively. Further, bushings 31 to 36 are attached to the containers of each phase. 51 is an antenna. In the figure,
Three antennas, 51U, 51V, and 51W, are shown. This is because one antenna 51 is placed at the position 51U in the figure when performing U-phase insulation diagnosis, and when performing V-phase insulation diagnosis. At the position of 51V in the drawing, it is shown that the W-phase insulation diagnosis is performed at the position of 51W when performing the insulation diagnosis.

As the antenna 51, one antenna is used in combination with the partial discharge detection antenna 52 and the noise detection antenna 62. That is, when used as the partial discharge detection antenna 52, the elements of the antenna 51 are arranged vertically so that the length directions of the bushings 31 and 32 and the plane of polarization of the antenna match. When the antenna 62 for detecting partial discharge is used, the antenna is
It is rotated by 0 ° so that the elements are arranged in the horizontal direction so that the lengthwise direction of the bushings 31 and 32 are orthogonal to the plane of polarization of the antenna.

In the figure, the noise detecting antenna 62 is shown by a broken line to distinguish it from the partial discharge detecting antenna 52. When attempting to detect a U-phase partial discharge using the antenna 51 configured as described above, the antenna 51U is arranged at a position where the two U-phase bushings 31 and 32 can be seen to overlap each other. When detecting V-phase or W-phase partial discharge, set antennas 51V and 51W to V
The two bushings 33 and 34 of the phase or the two bushings 35 and 36 of the W phase are moved to a position where they can be seen to overlap with each other.

When one antenna is used together, the output cable is one cable 7. Therefore, when the antenna 51 is used as the partial discharge detection antenna 52, the cable 7 is connected to the partial discharge terminal, and when the antenna 51 is used as the noise detection antenna 62, the cable 7 is connected to the noise terminal. To be 2 and subsequent figures, the determination device 9 only shows the changeover switch 91, but the configuration of the determination device 9 is the same as that in FIG. 1 described above.

When one antenna 51 is used for both partial discharge detection and noise detection as in this example, the noise detection antenna 62 not only rotates its polarization plane by 90 °, but also the electrical equipment to be diagnosed. It can also be turned in a different direction. (Embodiment 3) FIG. 3 shows an example in which the insulation performance of three phases is collectively diagnosed in a three-phase tank type gas circuit breaker. In the description of this example, only points different from the above-described second embodiment will be described.

In this example, the position where the antenna 51 is arranged is different from that of the electric device 11. Antenna 51
Are three-phase bushings 31, 32, 33 and 34, 3
5 and 36 are arranged at positions where they can be seen overlapping each other. Therefore, no matter which of the three phases the partial discharge occurs, the electromagnetic wave due to the partial discharge can be detected. If the partial discharge is detected here, the phase in which the partial discharge has occurred can be specified by executing the diagnosis according to the second embodiment.

For the three-phase collective diagnosis, instead of arranging the antenna 51 at the position shown in the figure, the antenna is sufficiently separated from the electric equipment so that the electromagnetic waves radiated from the three-phase bushing are generated by one antenna. It is also possible to detect with. (Embodiment 4) FIG. 4 shows an example in which a dual-system simultaneous output antenna is used as an antenna.

The illustrated antenna 53 is an antenna using a cross Yagi antenna, and this antenna 53 outputs a horizontal polarization component and a vertical polarization component simultaneously to separate coaxial cables 7 and 8. In this example, the cross Yagi antenna that detects the vertical polarization component is used as the partial discharge detection antenna 54, and the cross Yagi antenna that detects the horizontal polarization component is used as the noise detection antenna 64.

The cable 7 transmitting the output of the partial discharge detection antenna 54 is connected to the partial discharge terminal of the determination device 9, and the cable 8 transmitting the output of the noise detection antenna 64 is connected to the noise terminal. . Antenna 5 of this example
The use of 3 eliminates the need to rotate the antenna or switch the connection to the determination device 9 as in the first to third embodiments. Therefore, this example is suitable when the diagnostic device is permanently installed in the electric device.

The two-system simultaneous output antenna of this example is
The present invention is not limited to the illustrated cross Yagi antenna. For example,
A cross-type circularly polarized wave receiving antenna other than the cross Yagi antenna can be used, and the partial discharge detection antenna of the Yagi antenna and the noise detection antenna of the loop antenna can be combined. (Other Embodiments) In an environment to which the insulation diagnosis device of the present invention is applied, an electromagnetic wave may be generated by an aerial corona in the air. When the detection antenna detects this electromagnetic wave, there is a possibility of making an erroneous determination. The frequency band of electromagnetic waves of this air corona is 100 MHz to 200 MH.
The electromagnetic wave due to the partial discharge inside the electric device is about several MHz to 1 GHz or more. Therefore, by using the UHF antenna as the detection antenna, it is possible to prevent the detection of the electromagnetic waves due to the corona in the air and prevent the erroneous determination.

[0028]

According to the present invention, it is possible to install an antenna in an electrical equipment insulation diagnostic device that detects an electromagnetic wave due to partial discharge using an external antenna, without blackout work or dangerous work. You can

[Brief description of drawings]

FIG. 1 is a diagram showing a first example of an electric device insulation diagnosis apparatus of the present invention.

FIG. 2 is a diagram showing a second example of the electrical device insulation diagnosis apparatus of the present invention.

FIG. 3 is a diagram showing a third example of the electrical device insulation diagnosis apparatus of the present invention.

FIG. 4 is a diagram showing a fourth example of the electrical device insulation diagnosis apparatus of the present invention.

[Explanation of symbols]

 1, 11 ... Electrical equipment 2, 21, 22, 23 ... Container 3, 31-36 ... Bushing 4 ... Conductor 5, 52, 54 ... Partial discharge detection antenna 51, 53 ... Antenna 6, 62, 64 ... Noise detection Antenna 7, 8 ... Coaxial cable 9 ... Judgment device 91 ... Changeover switch 92 ... Amplifier 93 ... Tuner 96 ... CPU

Claims (2)

[Claims] 1. An antenna for detecting, from the outside of the electric device, an electromagnetic wave generated by the partial discharge generated inside the electric device having a bushing for pulling out a high-voltage conductor from the outside, and the electricity based on a signal detected by the antenna. In an electrical equipment insulation diagnostic device including a determination device for determining whether or not a partial discharge has occurred inside the equipment, the antenna has a gain for one-directional polarization, and the polarization plane is the length of the bushing. The electrical equipment insulation diagnosis device is characterized in that the electrical equipment insulation diagnosis device is arranged along the vertical direction. 2. A noise detection antenna having a plane of polarization aligned vertically to the length direction of the bushing, wherein the determination device detects the detection signal of the antenna for detecting the electromagnetic wave and the noise detection antenna. The electrical device insulation diagnosis apparatus according to claim 1, wherein it is determined whether or not a partial discharge has occurred inside the electrical device based on a detection signal of the antenna.