JPH02311104A - Compressed gas insulation switching device - Google Patents

Abstract

PURPOSE:To rise reliability by providing a coupling electrode detecting a micro partial discharge within a compressed gas insulation switching device at the outside thereof and by pulling out an electromagnetic wave signal due to the micro partial discharge via a coupling insulator provided at a flange of a tank to the outside thereof. CONSTITUTION:When within a compressed gas insulation switching device(GIS), e.g. a foreign material of a metal wire exists and a partial discharge is generated therefrom, an electromagnetic wave due to that propagates in the GIS via a high voltage conductor 1, passes through an opening 5 of a flange 4, and through a transmissible insulator 7 too and arrives at a coupling electrode 20. In brief, this results in that the electromagnetic wave within the GIS is pulled out to the outside of the GIS. The electromagnetic wave at the coupling electrode 20 is transmitted to high frequency electromagnetic wave measurement equipments such as a preamplifier, a spectrum analyzer and the like via a matching resistor 26 having a good transmission characteristic and high frequency coaxial cables 27, 14. Thereby, the inside micro partial discharge can be detected with good accuracy without generating gas leak.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a detector suitable for measuring minute partial discharges occurring inside a gas insulated switchgear (hereinafter abbreviated as GIS).

[Conventional technology]

In the conventional device, in order to detect minute partial discharges occurring inside the GIS, a coupling electrode is provided in the hand hole of the GIS tank, and a signal from this is guided to the outside of the GIS via a sealed terminal. Related to this type of device, see Hitachi Review voff, 7ONα8, pages 105 to 112, r overvariant f! "Equipment Predictive Maintenance System".

[Problem to be solved by the invention]

The above-mentioned conventional technology does not fully consider the airtightness of GIS and the signal transmission characteristics.

There were problems such as the possibility of gas leakage and the inability to faithfully transmit signals. That is, the former is due to the fact that the airtightness of the sealed terminal portion is not necessarily reliable. On the other hand, the latter is due to the fact that the conductor of the conventional sealed terminal simply passes through the tank, and cannot faithfully transmit high frequency signals of several MHz or higher.

The present invention is capable of detecting minute partial discharges inside a GIS, and aims to increase the reliability of the GIS so that gas leaks do not occur, and further aims to enable faithful signal detection. shall be.

[Means to solve the problem]

In order to achieve the above objective, the coupling electrode for detecting minute partial discharges inside the GIS is placed outside the GrS, and the electromagnetic wave signal due to minute partial discharges is output to the outside via the coupling insulator provided on the flange of the tank. This is what I did.

In order to achieve the other purpose, the sealed terminal used in the prior art is cut off and not used, and a well-known high frequency transmission system is used.

[Effect]

High-frequency electromagnetic waves of several MHz or higher generated by minute partial discharges do not pass through a metal body and are reflected, but are transmitted through an insulator. Further, gas-tightness can be achieved with either a metal body or an insulator. Therefore, an insulating plate was used as a cover plate for a predetermined GIS handhole so that high-frequency electromagnetic waves could be guided to the outside of the GIS.

In addition, conventional sealed terminals are small through bushings,
Since the impedance of the through conductor varies depending on its position in the length direction, high-frequency electromagnetic waves cannot be faithfully transmitted. However, in the present invention, the electromagnetic waves are guided outside the GIS, so the electromagnetic waves appearing at the coupling electrode provided outside are transmitted to the appropriate high-frequency It can be transmitted via cable to a designated measuring device.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

For example, the cross section of a GIS gas bus line is as shown in Figure 1, where a coaxial cylindrical high voltage conductor 1 and a pressure tank 2 are connected to an SF of several atmospheres.
It is insulated with e-gas 3 and mechanically supported by a spacer (not shown). in general.

A hand hole is attached to the tank 2 for installing an adsorbent. In the present invention, a special hand hole 4 is provided in the tank 2 as shown in FIG. That is, this hand hole 4 is provided with a flange 6 at an opening 5 protruding from the tank 2, and the flange 6 is provided with an insulating transparent plate 7 of the present invention. A coupling electrode section 8 and a metal plate 9 are attached in a sandwich manner. For mounting, holes are provided around the periphery, and these are tightened with bolts 10 and nuts 11 to be fixed to the flange 6. Further, a signal extraction hole 12 is opened in the metal shoulder plate 9, and a signal relay box 13 is further provided in the metal plate 9. Though not shown, an electromagnetic wave signal is transmitted from the relay box 13 to a spectrum analyzer via a pre-stage amplifier of the electromagnetic wave measuring device 1, for example, through a predetermined high-frequency coaxial cable 14 (not shown).

Note that the flange 6 is provided with a circumferential groove 15, and the GI
The airtightness of S can be ensured.

Details of the coupling electrode section 8, relay box 13, etc. are shown in FIG.
The coupling electrode section 8 is composed of a coupling electrode 20 facing the insulating transparent plate 7, a film sheet 21 (for example, Kapton film), and a ground electrode 22. The ground electrode 22 is connected to the metal plate 9 via a connecting portion 23 to ensure a ground potential. Film sheet 21. A signal extraction through hole 24 is provided in the ground electrode 22, and the signal of the coupling electrode 20 is extracted from a connection point 25, and is connected to a conductor and a matching resistor 26.
(attached if necessary) via high frequency coaxial cable 2
7, through the through hole 28 provided in the metal plate 9,
led outside. Note that the sheath 29 of the high frequency coaxial cable 27 is connected to the ground electrode 22.

The high frequency coaxial cable 27 reaches the high frequency coaxial cable 14 via the relay box 13.

If a foreign object, for example a metal wire, is present inside the GIS and a partial discharge is generated therefrom, electromagnetic waves caused by this will propagate inside the GIS via the high voltage conductor 1.

That is, electromagnetic waves propagate from the conductor 1 toward the tank.

In the case of the present invention, this electromagnetic wave passes through the opening 5 of the flange 4 and also passes through the insulating transparent body 7 to reach the coupling electrode 20. In other words, the electromagnetic waves inside the G-IS are extracted to the outside of the GIS. The electromagnetic waves of the coupling electrode 20 are transmitted through a matching resistor 26 with good transmission characteristics and a high frequency coaxial cable 27.
Via 14.

The signal is transmitted to a high-frequency electromagnetic wave measuring device such as a preamplifier or spectrum analyzer.

According to this embodiment, high-frequency electromagnetic wave signals of several MHz or higher due to minute partial discharges generated inside the GIS can be extracted to the outside of the GIS, and the same airtight structure as the conventional one can be used, which prevents gas leakage from occurring. Therefore, internal minute partial discharges can be detected with high accuracy. Another advantage is that this measurement system can also be used to measure high frequency surge voltages generated between the conductor 1 and the tank 2.

FIG. 3 shows a modification of the present invention, in which an attenuation reducing metal 50 is provided on the insulating and transparent plate 7 when the space of the opening 5 of the handhole 4 interferes with the propagation of electromagnetic waves. In this way, there is an effect of detecting minute partial discharges similar to when a coupling electrode is placed inside a GIS.

FIG. 4 shows another modification, in which the metal plate 9 in FIG. 1 is omitted. Although it has the effect of making the configuration simpler, the combination f! ! A cover 60 for the pole portion 8 is required. of course,
The ground electrode 22 in the coupling electrode section 8 is configured to have the same potential as the tank 2 .

In addition, in FIG. 2, the coupling electrode 20 and the ground electrode 12 can also be formed by vapor depositing metal on a film sheet 21. In this case, there is an effect that the installation becomes easier.

〔Effect of the invention〕

According to the present invention, without using a sealed terminal as in the past,
The combination of the hand hole provided in the GIS tank and the insulating transparent plate allows the internal high-frequency electromagnetic waves to be guided to the outside, so it is possible to detect minute partial discharges generated inside the GIS without causing gas leakage phenomena. I can do it.

Furthermore, since signals can be transmitted using a high-frequency coaxial cable without using sealed terminals, internal high-frequency electromagnetic waves can be faithfully transmitted to the measuring device.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a GIS minute partial discharge detection section according to an embodiment of the present invention, FIG. 2 is a cross-sectional view of the coupling electrode portion of FIG. 1,
3 and 4 are sectional views of second and third embodiments of the present invention, respectively. 4... Hand hole, 6... Flange, 7... Insulating transparent plate, 8... Coupling electrode part, 20... Coupling electrode,
21... Film sheet, 22... Ground ffi pole, 26... Match 231 Figure 2 Figure 3

Claims (1)

[Claims] 1. In a gas insulated switchgear using SF_6 gas, an opening is provided in the pressure tank, an insulator that can transmit electromagnetic waves is provided on the flange of the opening, an airtight structure is formed, and the insulator is connected to the atmosphere side. A gas insulated switchgear, characterized in that an electrode part is attached, the electromagnetic waves are measured from the electrode, and partial discharge generated inside the gas insulated switchgear is detected. 2. The gas insulated switchgear according to claim 1, further comprising a metal body for reducing electromagnetic wave propagation attenuation provided on the high-pressure gas side of the insulator through which the electromagnetic waves can pass. 3. The gas insulated switchgear according to claim 1, wherein a coupling electrode portion is provided on the atmosphere side of the insulator that transmits the electromagnetic waves, and further a metal body serving as mechanical reinforcement is placed outside. 4. The gas insulated switchgear according to claim 1, wherein the coupling electrode section is composed of a coupling electrode, an insulating film sheet, and a ground electrode. 5. The gas insulated switchgear according to claim 1, wherein the coupling electrode portion is disk-shaped. 6. The gas insulated switchgear according to claim 1, wherein the coupling electrode of the coupling electrode portion has a linear shape or a strip shape. 7. A gas insulated switchgear according to claim 1, characterized in that a solid insulator made of filled epoxy resin is used as the insulator that transmits electromagnetic waves. 8. The gas insulated switchgear according to claim 1, characterized in that a plurality of detection parts are provided. 9. In gas insulated switchgear using SF_6 gas,
An opening is provided in the pressure tank, an insulator is provided on the flange of the opening to create an airtight structure, and a coupling electrode section consisting of a coupling electrode, an insulating film/sheet, and a ground electrode is provided on the atmosphere side of the insulator. A gas insulated switchgear characterized by: 10. In gas insulated switchgear using SF_6 gas, an opening is provided in the pressure tank, an insulator is provided on the flange of the pressure tank, an airtight structure is provided, and a coupling electrode is provided on the atmosphere side of the insulator, and the inside of the gas insulated switchgear is A diagnostic system characterized by detecting partial discharge. 11. The diagnostic system according to claim 10, wherein the diagnostic system locates the position of the partial discharge and determines the progress of the insulation abnormality.