JPH01161634A - Insulating gas expansion type automatic blasting off breaker with electric field distribution screen - Google Patents

Abstract

PURPOSE: To increase dielectric strength, and improve arc-extinguishing capacity by providing a specific conductive screen where a movable arc contact point is arranged inside a breaking chamber. CONSTITUTION: This circuit breaker is composed of a pair of mutually separable arc contact points 32 and 20 arranged in a breaking chamber 12 housed in a casing 10, at least a single gas exhaust conduit 54 and 56 extending in a hollow arc contact point to communicate the breaking chamber 12 with the other part of the casing 10 as a gas expanding chamber and an orifice 18 arranged in the breaking chamber 12 to pass the movable arc contact point 20. The movable arc contact point 20 has a conductive screen 58 arranged inside the breaking chamber 12 to uniformly distribute an electric field in a breaking clearance 36, and a screen 58 forms a guide means to flow out gas toward the conducits 54 and 56 to communicate with the expanding chamber. Therefore, excellent dielectric strength and high arc-extinguishing capacity can be provided.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a self-blowing method by expansion of a high dielectric strength gas, in particular sulfur hexafluoride, contained in a sealed casing containing one or more poles. In a circuit breaker or switch,
Each stool comprises: - a pair of mutually separable arcing contacts disposed in a cut-off chamber housed in the casing; a self-blowing circuit breaker configured to consist of at least one gas exhaust conduit extending into a hollow arc contact; and - an orifice arranged in a disconnection chamber for passage of a movable arc contact; It is related to switches.

[Prior Art and Problems] In high-voltage circuit breakers or shielded receivers used, for example, in circuits with voltages above 70 kV, the distribution of the electric field inside the circuit break chamber can be controlled by a hemispherical metal hood.

Due to the increase in total dielectric strength inside the self-expanding circuit breaker, especially after breaking, the insertion of such a large metal hood inside the breaking chamber will result in irregular gas exhaust flow at the level of the root of the arc. The problem arises.

Although the use of a hood does increase the dielectric strength, it partially obstructs the insertion of the internal conduit of the tubular contact and thus limits the rate of gas flow into the expansion chamber. As a result, the amount of mass transfer due to gas expansion decreases, and there is a risk that the arc will not be extinguished.

[Objects and Effects of the Invention] An object of the present invention is to provide a gas-expandable self-blowing circuit breaker or switch having excellent breakdown strength and high arc-extinguishing ability.

[Summary of the Invention] In the circuit breaker of the present invention, the movable arc contact comprises a conductive screen disposed inside the breaking chamber to uniformly distribute the electric field in the breaking gap, and the screen is arranged inside the breaking chamber. It constitutes a guide means for causing gas to flow out toward a conduit communicating with the pipe.

the screen comprises radial vanes fixed to the outer periphery of the movable arc contact, defining grooves between the vanes;
Facilitating the flow of SF6 gas into the inlet of the internal conduit of the tubular arc contact, the presence of the screen on the movable arc contact does not reduce the flow of gas into the expansion chamber.

To rotate the arc, a coil or permanent magnet can be combined with a fixed arc contact inside the breaking chamber.

[Example] Hereinafter, the present invention will be described in detail with reference to the drawings. The following examples are for illustrating the present invention, but the present invention is not limited thereto.

The medium-voltage or high-voltage circuit breaker or switch illustrated in FIG. Filled with SF. This cylindrical casing 10 houses a pole with a separable contact system and an arc rotary-5F6 gas expansion automatic blowout device.

Inside the casing 10 there is arranged a blocking chamber 12 which comprises a rotating surface 14 of conductive material and an insulating bottom plate 16 with a passage orifice 18 for the movable arc contact 20;
It consists of a conductive cover 22 fixed to a current-carrying tube 24.

The current-carrying tube 24 extends along the longitudinal axis of the pole and is connected to the disconnection chamber 1.
Acts as a support for 2. One connection terminal constituted by the conductive cover 26 of the casing 10 is electrically connected to the fixed current-carrying tube 24 . Insulating bottom plate 1
6 ensures electrical insulation between the movable arc contact 20 and the end of the cylindrical surface 14 carrying the fixed main contact 28.

An electromagnetic coil 30 is arranged inside the interrupting chamber 12 , and the coil 30 has a rear end surface mechanically and electrically connected to the upper metal cover 22 and a movable arc contact 20 .
It has a front end face covered with a fixed arc contact 32 which is arranged opposite to the front end and acts as an arc movement area.

The auxiliary electrode 34 is directed towards the interruption gap 36 and is connected to the cover 2
It is electrically connected to 2. The partial shunting function of the coil 30 by the electrode 34 during the arcing period is described in detail in Japan Special Training No. 73945/1987.

The main stationary contact 28 cooperates with a movable main contact 38, which is a tulip-shaped contact carried by a conductive support 40 of the movable device in electrical connection with the other terminal (not shown). Consists of. By inserting a compression spring 42 between the shoulder 44 of the support 40 and the distal end 46 of the movable arc contact 20 opposite from the interruption gap 36,
The movable arc contact 20 is mechanically telescopically coupled to the movable main contact 38 for relative translational movement. During opening of the disconnection device, the spring 42 springs the movable arc contact 20 towards the extended position, regaining the dead space (d) and bringing the distal end 46 of the movable arc contact 20 into abutment against the drive tappet 48 of the support 40. .

The stationary current-carrying tube 24 and the support 40 of the mobile device are each configured as a coaxial conduit 54,56, connecting the isolation chamber 12 to the SF6.
It communicates with other parts of the casing 10 forming a gas expansion chamber. As a result, expansion of SF6 gas through conduits 54,56 results in double automatic blowout of the arc.

According to the invention, the upper part of the movable arc contact 20 located inside the breaking chamber 12 carries an electric field distribution screen (FIG. 2) in the breaking gap 36. This screen 58 is
It consists of a plurality of vanes 60 each fixed on a radiation surface at constant angular intervals on the outer circumference of the movable arc contact 20. A series of grooves or groups 6 in the middle of these radial vanes 60
4 (FIG. 3) is present to facilitate the flow of gas towards internal conduit 54, 56 during the expansion phase of gas SF.

The functions of the circuit breaker shown in FIGS. 1 to 3 are as follows.

The closed position is shown in the right half of FIG. It is clear that in this case the majority of the current flows along the main circuit containing the main contacts 28,38. Due to the reactance of the coil 30, a portion of the current passes through the arc contact 32.20 of the parallel arc circuit and the coil 30.

Opening of the circuit breaker is initiated by sliding the support 40, which is mechanically connected to the actuating lever (not shown), downward in FIG. A main contact 28.38 located outside the breaking chamber 12 opens before the arc contact 32.20. In the first stage of the opening movement, the dead space (d
) and the stretching action of the spring 42, the movable arc contact 20
is in contact with the fixed arc contact 32. A current is commutated into the parallel arc circuit, energizing the coil 30 and creating a magnetic field.

In the second stage of opening the circuit breaker, the arcing contacts 32, 20
open to each other, and the arc 66 is rotated by the magnetic field of the coil 30. This arc produces a heating effect and an increase in the gas pressure of the SF gas inside the isolation chamber 12, which passes through the internal conduits 54, 56 to the casing 1.
You can escape towards 0's expansion chamber.

The combination of the rotating magnetic field blowing effect of the arc and the vapor phase blowing effect of the expanding gas provides rapid arc extinction.

Due to the presence of the electric field distribution screen 58 in the interruption gap 36, near zero current, the arcing contact 32.
20, or between the movable arc contact 2o and the auxiliary electrode 34, restarting the arc can be completely prevented. The presence of the separation grooves 64 between the vanes 60 also facilitates the flow of SF gas toward the orifices of the conduits 54, 56, allowing a gas flow rate sufficient to blow out the gas of the arc.

Of course, instead of the screen 58 consisting of radial vanes 60, any other electrically conductive hood for electric field distribution can be used, which hood should be such that it does not impede the flow of gas from the isolation chamber 12 to the expansion chamber. Guiding means may be provided, for example a grid or a perforated hood.

According to other embodiments, casing 10 can include multiple poles. Moreover, a permanent magnet can be used instead of the coil 30 inside the cutoff chamber 12.

[Brief explanation of the drawing]

FIG. 1 is a partial axial sectional view of a gas-expandable circuit breaker equipped with a screen according to the present invention, FIG. 2 is an enlarged sectional view of the screen of FIG. 1, and FIG. 3 is an end view of the screen of FIG. 2. be. 10. Casing 12. ,,blocking chamber,16. ,,
Insulating bottom plate, 20,, Movable arc contact, 22.2B,
, , Conductive cover, 3200. Fixed arc contact, 28.
,, fixed main contact, 30. ,,coil,38. ,, movable main contact, 36. , , cutoff gap, 58. ,,Screen,6
0. ,, feather, 84. ,,Mizo,66,,,Arc,Deguchi agent Sato-'Yu FIG・1

Claims (1)

[Claims] 1. A sealed casing (10) containing one or more poles.
In a self-blowing circuit breaker or switch by expansion of a high dielectric strength gas, in particular sulfur hexafluoride, contained in a casing (10), each pole comprises: - a breaking chamber (12) contained in a casing (10);
A pair of mutually separable arc contacts (3
2, 20), - a casing (1) with the cutoff chamber (12) as a gas expansion chamber;
at least one gas exhaust conduit (54, 5) extending into said hollow arc contact to communicate with other parts of the
6), - a breaking chamber (12) for passing the movable arc contact (20);
an orifice (18) disposed within the interrupting chamber (12); Insulating gas with an electric field distribution screen, characterized in that it comprises a screen (58), said screen (58) forming a guiding means for the gas to flow out towards the conduits (54, 56) communicating with the expansion chamber. Expandable automatic blowout type circuit breaker. 2. The screen (58) has a tubular movable arc contact (
20), the gas outflow guiding means includes a plurality of metal vanes (60) arranged at regular angular intervals on a radial plane passing through the axis of the screen (58); The circuit breaker or switch according to claim 1, characterized in that the circuit breaker or switch is constituted by: 3. The circuit breaker or switch according to claim 2, characterized in that the blades (60) of the screen (58) are fixed to the outer periphery of the movable arc contact (20). 4. Fixed arc contact (32) and movable arc contact (20)
In order to generate a magnetic field in the breaking gap (36) which rotates the arc produced during the separation of the breaking chamber (12), a coil (
30) The circuit breaker or switch according to claim 1, further comprising a permanent magnet. 5. The insulating bottom plate (16) of the breaking chamber (12) is provided with an orifice (18) through which the movable arc contact (20) passes;
The isolation chamber (12) comprises a cover (22) of conductive material facing the bottom plate, and this cover (22) covers the coil (30).
), and the opposite end surface of the coil (30) is covered by a fixed arc contact (32), which faces the movable arc contact (20) and the screen (58). 5. Circuit breaker or switch according to claim 4, characterized in that it is arranged to act as a moving area for the arc.