JPH0570367B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a gas insulated switchgear suitable for preventing abnormalities such as flashover occurring in an insulator provided between sheaths housing conductors.

[Conventional technology]

Recently, as the demand for electric power increases, the capacity of substation equipment such as gas-insulated switchgear has increased. As the capacity of gas-insulated switchgear increases, the magnetic field generated when current is applied to the sheath of the gas-insulated busbar that connects equipment such as transformers and bushings to gas-insulated equipment such as circuit breakers and disconnectors increases. When leakage or fault current occurs, the electromagnetic force acting between the conductors of the gas-insulated bus increases. In particular, when a gas insulated bus bar is connected to a circuit breaker or disconnect switch, the sheath of gas insulated equipment is generally made of mild steel or stainless steel from the viewpoint of strength during operation. The sheath is made of aluminum, which has good weldability, from the viewpoint of ease of on-site welding work. Due to such a difference in sheath material, a large electromagnetic induction current generated on the gas insulated bus bar side flows into the gas insulated equipment side, causing the gas insulated equipment to overheat. For this reason, the Institute of Electrical Engineers of Japan Technical Report (Department) No.
No. 163, page 63, March 1980, the sheaths of the gas-insulated equipment and the gas-insulated bus bar, which are each grounded by the grounding wire 7, are electrically insulated and connected, and the electromagnetic induction described above is Current is circulated between each sheath phase. Specifically, as shown in FIGS. 2 and 3, for example, the flanges 3 and 4 of the sheath 1 on the gas insulated equipment side and the sheath 2 on the gas insulated bus bar side are connected through an insulator 5. In addition to connecting, the aforementioned sheath 1 and sheath 2
Short-circuit bodies (hereinafter referred to as inter-phase short-circuit bodies) are provided between the phases to electrically connect them in the vicinity of the connection portions.

[Problem to be solved by the invention]

In the above-mentioned conventional technology, it is possible to alleviate the influence of electromagnetic induction current that occurs when energizing, but sheath 1 and sheath 2
A high potential difference is generated between the two. In order to reduce this high potential difference, it is necessary to minimize the distance between the grounding positions of the grounding wires 7 of the sheaths 1 and 2.
Depending on the configuration of the substation, it may not be possible to arrange the grounding wire 7 near the flanges 3 and 4 of each sheath 1 and 2. For this reason, flashover occurs on the surface of the insulator 5 provided between the flanges 3 and 4 of the sheaths 1 and 2 due to the high potential difference between the sheaths 1 and 2.
There was a problem in that the reliability of the equipment was significantly reduced.

An object of the present invention is to provide a gas insulated switchgear that can prevent flashover on the surface of an insulator between sheaths caused by a potential difference due to a surge voltage.

[Means to solve the problem]

In order to achieve the above object, the present invention accommodates a conductor inside a sheath, juxtaposes three-phase separated gas-insulated busbars connected by an insulator, and grounds the sheath by a grounding wire. , in a gas-insulated switchgear in which phase-to-phase shorting bodies are provided on both sides of the insulator in the sheath to electrically connect each phase of the sheath, at one location between the sheaths connected via the insulator. , a short circuit body is provided to electrically connect these.

[Effect]

The surge voltage generated when opening and closing gas-insulated equipment increases the potential of its sheath and creates a high potential difference between this sheath and the sheath of the gas-insulated bus bar connected to it, but the surge voltage generated in the sheath on the gas-insulated equipment side The potential is transferred to the sheath on the gas insulated bus bar side through the short circuit. As a result, the potential difference between the sheath on the gas insulated equipment side and the sheath on the gas insulated bus bar side becomes small, and it is possible to prevent the occurrence of flashover on the surface of the insulator provided between the sheaths.

〔Example〕

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

FIG. 1 shows an embodiment of the present invention, and in this figure, the same reference numerals as in FIGS. 2 and 3 are the same parts. A phase-separated sheath 1 on the side of gas insulated equipment such as circuit breakers and disconnectors, and a phase-separated sheath 2 on the side of the gas insulated bus bar connected to this are insulating materials between the flanges 3 and 4 provided at their ends. 5 and are electrically insulated and connected. A conductor is housed in each of the sheaths 1 and 2 described above. The sheath 1 on the gas insulated equipment side and the sheath 2 on the gas insulated bus bar side are electrically connected by interphase shorting bodies 6 provided near the flanges 3 and 4, respectively. The interphase shorting body 6 on the sheath 1 side and the interphase shorting body 6 on the sheath 2 side are electrically connected at only one point by a shorting body 8.

With the above configuration, when a circuit breaker or disconnector, which is a gas insulated device, opens or closes, a surge voltage is generated accordingly. This surge voltage charges the sheath 2 on the gas insulated equipment side. Therefore, a high potential difference occurs between the sheath 1 on the gas insulated equipment side and the sheath 2 on the gas insulated bus bar side. Since the potential in the sheath 1 on the gas insulated equipment side is transferred to the sheath 2 on the gas insulated bus bar side by the interphase short circuit 6 and the short circuit 8, the potential difference between the sheaths 1 and 2 can be reduced. As a result, sheath 1,
It is possible to prevent flashover from occurring on the surface of the insulator 5 provided between the two.

In addition, since the interphase shorting body 6 on the sheath 1 side and the interphase shorting body 6 on the sheath 2 side are connected at only one point by the shorting body 8, the electromagnetic induced current flowing in the sheaths 1 and 2 flows through the shorting body 8. Since they do not flow and do not affect each other, local heating of the sheath can be prevented. If the interphase short-circuit bodies 6 are electrically connected by two short-circuit bodies 8, electromagnetic induction current will flow to the other side through these short-circuit bodies 8, causing local heating of the sheath. .

Note that only one phase of the flange connection portion may be electrically connected by a short circuit.

〔Effect of the invention〕

According to the present invention, both sides of the insulating connection part of the sheath are
Since electrical connection is made using two short-circuiting bodies, it is possible to reduce the potential difference between the insulated connection parts of the sheath caused by surge voltage when opening and closing gas insulated equipment such as circuit breakers and disconnectors. As a result, occurrence of flashover at the insulated connection portion can be suppressed and reliability can be improved.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing an embodiment of the gas insulated switchgear of the present invention, FIG. 2 is a front view of a conventional gas insulated switchgear, and FIG. 3 is a plan view of FIG. 2. 1, 2...sheath, 3, 4...flange, 5...
...Insulator, 6...Interphase short circuit, 7...Grounding wire, 8
...Short circuit body.

Claims (1)

[Scope of Claims] 1 A conductor is housed inside a sheath, and three-phase separated gas-insulated busbars connected by an insulator are juxtaposed,
In a gas insulated switchgear, the sheath is grounded by a grounding wire, and phase-to-phase shorting bodies are provided on both sides of the insulator in the sheath to electrically connect the phases of the sheath, the gas insulated switchgear including: A gas insulated switchgear characterized in that a short-circuiting body is provided at one location between the sheaths connected together to electrically connect them. 2. The gas insulated switchgear according to claim 1, wherein the short-circuit body connects the interphase short-circuit bodies. 3. The gas-insulated switchgear according to claim 1, wherein the short-circuit body connects one-phase sheaths connected via an insulator.