JPH0775130B2 - Gas insulated switchgear - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas-insulated switchgear, and in particular, a tank in which an insulating gas is sealed contains a disconnecting switch having a fixed contact and a movable contact each provided with a shield. The present invention relates to a gas insulated switchgear.

The disconnector of this type of gas-insulated switchgear may generate an abnormal voltage when the charging current of the circuit is opened and closed. Conventionally, in order to protect the device from such an abnormal voltage, a lightning arrester is generally provided in the circuit. However, the present invention does this by improving the disconnecting switch itself, and provides a gas-insulated switchgear which is economical and highly reliable, and is particularly effective especially at 500 kV or higher where the system voltage increases. The purpose is.

The drawings show an embodiment of the present invention, in which a first fixed-side shield 4 surrounding a fixed contact 3 is provided inside a tank 2 of a disconnector 1 between a tank 5 and a tank 2 of a gas insulated switchgear. It is attached to the sandwiched insulating spacer 6 through the conductor 6a and the adapter 7, and the second fixed side shield 8
Is electrically and mechanically connected to the first fixed-side shield 4 through an annular insulator 12 in which a high-resistance element or an impedance 11 such as a zinc oxide type lightning arrester is cast on the side of the movable-side shield 10 surrounding the movable contact 9. Are combined together. Reference numeral 5a is a conductor, and 13 is an adapter inserted at both ends of the insulator 12.

With this configuration, when the charging current is released, the movable contact 9
The arc A1 generated between the movable contact 9 and the first fixed side shield 4 then moves between the movable contact 9 and the first fixed side shield 4, but when the voltage between them becomes high, the arc A1 moves between the movable contact 9 and the second fixed side shield. Move between 8 and. Here, by appropriately selecting the gear gap between the movable contact 9 and the second fixed side shield 8 to be several mm or more,
The arc A ₁ smoothly transitions as described above. Ark A ₁
When is shifted to the second fixed side shield 8, the impedance 11 is inserted into the circuit, and the level of the abnormal voltage is greatly reduced. Then, in the vicinity of the position where the movable contact 9 reaches the position shown by the dotted line, the arc A ₂ is broken or broken. When the disconnecting switch is turned on, the abnormal voltage level can be suppressed in the opposite way.

In the above, when the impedance 11 is cast on the annular insulator 12, the impedance 11 can be arranged in a spiral shape, and the dimension L can be made small, so that the disconnector can be made smaller.

Further, by disposing the second fixed side shield 8 between the fixed side shield 4 and the movable side shield 10, the inner diameter of the tank 2 can be made small and a small gas insulated switchgear can be obtained.

As the impedance 11, various elements such as a high resistance element, a zinc oxide type lightning arrester element, a combination thereof, a capacitor, a semiconductor element and the like are conceivable. Since the energy to be processed is small, it can be freely selected.

Further, as the insulator 12, in addition to the annular shape, many cylindrical shapes can be adopted. In addition to casting, there are no restrictions on the structure such as the mold or laminated plate, and on the material.

As described above, the present invention provides a lightning arrester,
With a simple structure provided between the first fixed-side shield and the movable-side shield of the disconnector, there is an effect that an economical and highly reliable gas-insulated switchgear can be obtained.

[Brief description of drawings]

The drawings are side elevational views of the essential portions of an embodiment of the present invention. 1 ... Gas-insulated switchgear, 2 ... Tank, 3 ... Fixed contact, 4 ... First fixed-side shield, 5 ... Gas-insulated switchgear tank, 5a ... Conductor, 6 ... Insulating spacer, 6a …… conductor, 7 …… adapter, 8 …… second fixed side shield, 9 …… movable contact, 10 …… movable side shield, 11 …… impedance, 12 …… insulator, 13 …… adapter, A ₁ , A ₂ …… Ark.

Claims (7)

[Claims] 1. A gas-insulated switchgear comprising a disconnector having a fixed contact and a movable contact, each of which is surrounded by a shield, and a first fixed-side shield that surrounds the fixed contact and a movable-side shield that surrounds the movable contact. A second fixed-side shield disposed between the first and second fixed-side shields, and a disconnector having a built-in impedance and an insulator coupled between the first and second fixed-side shields. Gas insulated switchgear. 2. The gas insulated switchgear according to claim 1, further comprising an insulator made of a cast insulator. 3. The gas insulated switchgear according to claim 1, further comprising a gear provided between the second fixed shield and the movable contact. 4. The gas-insulated switchgear according to claim 1, further comprising an impedance formed of a high resistance body. 5. The gas-insulated switchgear according to claim 1, further comprising an impedance formed of a zinc-alloy lightning arrester. 6. The gas insulated switchgear according to claim 1, further comprising an annular insulator. 7. The gas insulated switchgear according to claim 6, which has a spiral impedance.