JPS5959005A - Gas insulated cubicle - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a gas insulated cubicle in which electrical equipment is housed in a grounded metal container and insulated by filling an insulating gas in the metal container.

[Technical background of the invention and its problems]

Recently, the rated voltage of power receiving and transforming equipment for electric power and general industry has increased to 6.
6777kzv class high voltage cubicles have improved insulation properties, and gas insulation cubicles with excellent insulation properties have come into use with the goal of reducing the installation area through miniaturization. .

This gas insulated cubicle houses a large number of electrical devices such as busbars, circuit breakers, disconnectors, etc. in a grounded metal container and performs electrical connections. The cubicle is insulated.

However, the 8F6 gas used as the insulating gas causes accidents such as ground faults and short circuits in the metal container, causing arcs to occur, and the high-temperature arc energy generates decomposition gas. The decomposition gas is low grade sulfur fluoride, SF4.
p S F 2 r 52Ft, etc., and S”2
# 5tFz"J' is due to high temperature heating by arc,
It is further decomposed into SF as in another formula.

2・SF, →SF, -4-8 2・82F, →SF, -1-8 Also, if there is water in the cracked gas, the main component is SF.

is hydrolyzed to produce 80F as a secondary product as shown in the following formula.
and generates HF.

S Fj 10H2O-+ SOFt +2・HF This decomposed gas is toxic, has a bad odor, and has an adverse effect on the human body.
It is recommended that pm. In addition, this decomposed gas corrodes the metals that make up electrical enclosures, has a negative effect on some insulators such as epoxy resin, and has an adverse effect on electrical insulation such as reducing creepage insulation, resulting in high power. In the case of insulation cubicles, measures against decomposed gas in the event of an accident are limited to +3U.

[Purpose of the invention]

The object of the present invention is to eliminate the above-mentioned drawbacks, suppress the generation of decomposed gas in the event of an accident, provide excellent insulation properties, and provide a safe gas-insulated cubicle that does not adversely affect the surroundings or the human body.

[Summary of the Invention] In order to achieve the above object, the present invention focuses on the point that the amount of decomposed gas generated is proportional to the arc energy at the time of an accident, and reduces the arc energy and energy in the small region.

That is, by detecting the initial fault of a one-phase ground fault that occurs in electrical equipment, and installing a grounding device that has an operation mechanism for each phase independently, the arc can be quickly extinguished by turning on fL. , Progress to a larger short-circuit accident 1. Explosion-proof,
It is characterized by preventing toxic decomposition gas from being released to the outside.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to the drawings.

Figure 1 shows a single-wire circuit for electrical equipment installed in a gas-insulated cubicle.As shown in the figure, a busbar 2 is connected to a cable head 1 introduced from the primary side of the transformer.
, via the disconnector 3, the breaker 4, the CT5, and the disconnector 3,
On the power side of the circuit breaker 4 leading to the load limiter Ifae and on the load side of C'r 5, there is an operation 11 for each phase individually! A grounding device 7 having a structure is provided.
, etc. are provided, and these are housed in a metal container 10 as shown in FIG. The metal container 10 is filled with SF and gas and is insulated.

The insulation strength within this metal container 10 is generally designed to be stronger for inter-phase insulation than ground insulation in order to emphasize the insulation of each electrical device. Accidents occur quickly.

In addition, it has been confirmed that the amount of decomposition gas generated by arc energy is sometimes proportional to the magnitude of the arc current value, as shown in Figure 3, taking the case of a Cu electrode as an example.
ing. The present invention provides a grounding device 7 having an independent operation mechanism for each phase.
Since the ground fault current or ground fault phase voltage 1cT5 or PT/? caused by an accident is provided, By performing detection using the above method, only the grounding device 7 of the ground fault phase is forcedly grounded promptly. Since the neutral point resistance of the 66/77 class is a high resistance ground, the ground fault current is 100 to 20
It is about 0A.

With this level of ground fault current, n is the operation PjA of the grounding device 7.
The structure uses an energy storage spring system, and after the ground fault torrent flows,
It is possible to make forced grounding in a short period of ~4 cycles. Therefore, the arc current generated in the SF or gas due to an accident is quickly transferred to the grounding device, so that subsequent accidents with large arc energy such as mutual short circuits do not occur. In a typical cubicle, the time it takes to transition from a ground fault to a short circuit is 0.5 seconds or more.

〔Effect of the invention〕

According to the present invention, the arc current is detected when a one-phase ground fault occurs, and the arc current is forcibly grounded by the grounding device, so the generation of decomposition gas A'1 can be suppressed, and the three-phase Since short circuits are prevented, explosions due to internal pressure increases are eliminated, and toxic decomposed gases are not released outside the cubicle, making it possible to provide a safe gas-insulated cubicle with excellent insulation properties.

[Brief explanation of the drawing]

Figure 1 is an AA connection circuit diagram showing an example of the gas insulated cubicle of the present invention, Figure 2 is a sectional view showing an example of the gas insulated cubicle of the present invention, and Figure WJ3 is the generation of arc current and decomposed gas. It is a characteristic diagram showing the amount. 1... Cable head, 2... Bus bar, 3... Disconnector, 4... Breaker, 5... C'r, 6... Load side bus bar, 7... Grounding installation , 8...P, T, 9...
Lightning arrester, 10...metal container. Applicant's agent Patent attorney Hiko Rin Ushiki

Claims (1)

[Claims] Grounding 1 In addition, in a gas-insulated cubicle in which electrical equipment is housed in a metal container and insulated by filling an insulating gas in the metal container, a grounding device that can be operated independently for each phase of the electrical equipment is provided, A gas-insulated cubicle that detects single-phase ground faults that occur in equipment and operates the grounding device to ground the equipment.