JP3063067B2 - Partial discharge detector for gas insulated switchgear - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a partial discharge detector for detecting a partial discharge generated inside a gas insulated switchgear (hereinafter referred to as GIS).

[0002]

2. Description of the Related Art Generally, in GIS, when a partial discharge is generated from a high-voltage main circuit conductor in a metal gas container, insulation is deteriorated and there is a danger of dielectric breakdown. Devices for detecting have been proposed.

FIG. 3 shows an example. Tubular metal gas container 3a or 3b containing high-voltage main circuit conductor 9
The loop antenna 30 is wound around the outer periphery of the metal gas container 3a or 3b while maintaining insulation from the metal gas container 3a or 3b. Of the electromagnetic waves due to partial discharge generated inside the metal gas container 3a or 3b, The signal is received by the loop antenna 30 outside the container 3a or 3b, input to the measuring device 7a via the coaxial line 5a, and further input to the signal processing device 31, so that partial discharge is detected.

As another example, as shown in FIG.
Electrodes 40a and 40b are buried inside the insulating spacer 4 to receive the electromagnetic wave penetrating into the insulating spacer 4 and input this to the measuring device 7b via the coaxial line 5b and further to the signal processing device 41 to perform partial discharge. Is detected.

[0005]

In a conventional configuration in which a loop antenna is wound around the outer periphery of a metal gas container, the detection sensitivity of the partial discharge electromagnetic wave is poor because the metal gas container is electrically grounded. In addition, there is a drawback that it is easily affected by external noise and its application is limited to a place where electromagnetic noise is small.

In the method of embedding an electrode in an insulating spacer, a GIS having an insulating spacer in which an existing electrode is not embedded requires replacement of the insulating spacer, which significantly increases the reliability of equipment. There is a risk of damage.

Accordingly, the present invention is to provide a partial discharge detector which is less affected by external noise and can be easily applied to an existing GIS.

[0008]

According to a first aspect of the present invention, a stud bolt portion for fastening a joint between an insulating spacer of a gas insulated switchgear and a metal gas container has a metal stud having insulation for insulating the metal gas container. A bolt, an insulating ring passing through both ends of the stud bolt and insulating the metal gas container and the stud bolt, a connection terminal passing through one end of the stud bolt and electrically connecting to the stud bolt, and the stud bolt. A metal nut tightened from both ends, wherein the connection terminal and the measuring instrument are connected by a coaxial line.

According to a second aspect of the present invention, in addition to the configuration of the first aspect, a metal ribbon surrounding the outer periphery of the insulating spacer and electrically connected to the metal gas container is provided.

[0010]

When a partial discharge is generated inside the GIS, an electromagnetic wave accompanying the partial discharge propagates inside the metal gas container as a waveguide of a coaxial structure pipe of the GIS. At this time, since the insulating spacer is made of an insulator, the electromagnetic wave leaks outside from this portion. The stud bolt penetrating through the insulating spacer of the present invention functions as an antenna and receives the electromagnetic wave leaking to the outside. The received signal is measured by a measuring instrument via a coaxial line.

Usually, a metal cover electrically connected to a grounded metal gas container is provided on the outer periphery of the insulating spacer to improve the weather resistance of the insulator. It acts to reduce external noise. When the metal cover is not provided, external noise can be reduced by the metal ribbon wound around the outer periphery of the insulating spacer.

[0012]

FIG. 1 shows an embodiment of a partial discharge detector of a gas insulated switchgear according to the present invention. In the first embodiment, a joint between an insulating spacer 4 of a gas insulated switchgear and metal gas containers 3a, 3b is formed. A metal stud bolt 1 having insulation to insulate the metal gas containers 3a and 3b is passed through the holes for the stud bolts to be tightened. An insulating ring 20 to be connected and a connection terminal 8 for electrically connecting the stud bolt 1 to one end of the stud bolt 1 are fitted.
2b. The connection terminal 8 and the measuring instrument 7 are connected by the coaxial line 5.

When the electromagnetic wave leaking from the insulating spacer 4 to the outside passes through the stud bolt 1 penetrating the insulating spacer 4, the stud bolt 1 acts as a receiving antenna and can be measured as an electromagnetic wave signal by the measuring instrument 7. In this embodiment, a metal cover 6 is provided on the outer periphery of the insulating spacer 4, which has an effect of recommending external noise.

According to the second aspect, as shown in FIG. 2, when the metal cover 6 is not provided on the outer periphery of the insulating spacer 4, as shown in FIG. Turn, pull out the conductive wire 11 from the metal ribbon 10,
This is the addition of a thin metal strip 10 that connects the lead wire 11 drawn between the metal gas containers 3a and 3b and the insulating ring 20, and has the effect of reducing external noise when the metal cover 6 shown in FIG. 1 is not provided.

[0015]

The partial discharge generated inside the GIS is controlled by the GI
Regardless of the installation location of S, detection can be performed with high sensitivity by reducing the influence of external noise, and a partial discharge detector can be easily attached to an existing GIS.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of a partial discharge detector of a gas insulated switchgear of the present invention.

FIG. 2 is a diagram illustrating an example of an external noise shield in a case where a metal cover is not provided on an insulating spacer of the gas insulated switchgear according to the present invention.

FIG. 3 is a diagram showing an example of a partial discharge detector of a conventional gas insulated switchgear.

FIG. 4 is a diagram showing another example of the partial discharge detector of the conventional gas insulated switchgear.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Stud bolt 2a, 2b Hex nut 3a, 3b Metal gas container 4 Insulating spacer 5, 5a, 5b Coaxial line 6 Metal cover 7, 7a, 7b Measuring device 8 Connection terminal 10 Metal ribbon 20 Insulation ring

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G01R 31/12 H02B 13/065

Claims (2)

(57) [Claims] A stud bolt portion for fastening a joint between an insulating spacer of a gas insulated switchgear and a metal gas container, comprising: a metal stud bolt having insulation for insulation from the metal gas container; An insulating ring through which the metal gas container and the stud bolt are insulated,
A connection terminal that passes through one end of the stud bolt and is electrically connected to the stud bolt; and a metal nut that tightens the stud bolt from both ends. The connection terminal and the measuring device are connected by a coaxial line. A partial discharge detector for a gas insulated switchgear, characterized in that: 2. The partial discharge detector for a gas insulated switchgear according to claim 1, further comprising a metal ribbon surrounding the outer periphery of the insulating spacer and electrically connected to the metal gas container.