JPS5918597Y2 - Patshua type gas shield disconnector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a buffer type gas breaker which is compressed by a piston and cylinder device during the arc extinguishing gas breaker tripping operation and sprays the compressed gas onto the arc.

In recent years, with the increase in high voltage and capacity in electric power systems, the short-circuit current that must be interrupted by circuit breakers has rapidly increased, and the voltage applied to circuit breakers for current interruption and connection has also tended to increase.

In general, in a so-called buffer type gas breaker, which compresses arc-extinguishing gas using a cylinder and piston and sprays the compressed gas onto an arc generated between contacts, the arc-extinguishing gas is released from the arc when it passes through the arc. It is heated by the generated energy and is blown downstream as so-called hot gas.

This hot gas contains electrode vapor and decomposition products generated by the reaction between these and the arc-extinguishing gas, and is compared to the arc-extinguishing gas at rest due to the non-uniformity of density accompanying the gas flow. This causes a decrease in dielectric strength.

This phenomenon has been a drawback for the purpose of increasing the breaking performance per unit in the circuit breaker.

Therefore, one way to improve the blocking performance is to improve the flow path on the downstream side so that the high-temperature gas flow is not guided to areas where the electric field strength is high.

A conventional example of a buffer type circuit breaker in an arc extinguishing chamber is shown in FIG.

The arc-extinguishing gas compressed by the buffer piston 5 and buffer cylinder 6 is blown through the insulating nozzle 3 onto the arc 8 generated between the fixed arc contact 2 and the movable arc contact 4.

Arrows indicate gas flow.

The arc-extinguishing gas that has passed through the arc 8 becomes hot gas as described above, and is discharged from the exhaust port A attached to the base of the cylindrical member holding the fixed current-carrying contact 1 into a tank that is wider than the inside of the fixed current-carrying contact 1. Exhausted into space.

In such a conventional structure, the flow direction of the hot gas changes along the fixed contact mounting part 9 as shown by the arrow in FIG. In this case, there was a drawback that flashing and circuiting 10 often occurred from the vicinity of the corner of the fixed contact attachment part 90, where the electric field strength was stronger than the surrounding area, and the breaking performance could not be improved.

In order to prevent such a gas flow toward the tank wall, a structure in which a shield is provided to cover the outer side of the exhaust port has been considered.

With this type of configuration, the gas in the large tank space cannot be used to cool the hot gas that has passed through the arc, so it is necessary to have a large space inside the shield.
Since it is necessary to provide a sufficient insulation distance between the shield and the tank, there is a drawback that the breaker must have a large tank diameter as a result.

In addition, the inventors proposed a method to reduce the electric field strength as shown in Figure 2, in which the same parts as in Figure 1 are given the same reference numerals, as a way to eliminate the drawbacks caused by the hot gas flow flowing onto the tank wall. We have developed a configuration in which the shield 7 is attached to the outer periphery of the fixed contact attachment part 9.

However, even with this configuration, it is not possible to change the direction of the hot gas flow toward the tank wall as shown by the arrow, and further improvements are desired.

The present invention has been developed in view of the above points, and its purpose is to make it possible to directly utilize the entire space between the tank wall and the exhaust port as a cooling space for hot gas, and also to allow high-temperature gas to cool near the fixed contact mounting part. To obtain a buffer type gas breaker which prevents current from being blown directly onto a tank wall surface and improves withstand voltage characteristics after current interruption.

Next, the present invention will be explained based on an embodiment shown in FIG. 3, in which the same parts as in FIG. 1 are given the same reference numerals.

Similar to FIG. 2, FIG. 3 shows a cross section around the fixed contact and the fixed contact mounting portion.

At the outer periphery of the exhaust port A of the cylindrical member that holds the fixed current-carrying contacts at the outer edge of the mounting part 9 of the fixed arc contact 2 and the fixed current-carrying contact 1, etc., the fixed contact mounting part side of the mounting part 9 is attached. The exhaust cover 11 is mounted and arranged so as to extend by a distance from the movable contact element (not shown).

The distal end of the exhaust cover 11 has a cross-sectional shape that is curved inward toward the outer peripheral surface of the fixed contact and forms a circle or a part of a circle.

Furthermore, based on the experimental results, the relationship between the distance a extending from the fixed contact mounting portion 9 of the exhaust cover 11 toward the movable contact and the distance a from the central axis to the outer circumference of the exhaust cover 11 is as follows. It was found that it is desirable to place

By providing such an exhaust cover 11, the hot gas that has passed through the arc 8 generated when the current is cut off can be exhausted from the movable contact side surface of the fixed current-carrying contact 1 as shown by the arrow in FIG. After the flow direction is changed to the tank wall through the port A, the gas is returned to the movable contact side by the exhaust cover 11 and exhausted to a wide space inside the tank.

As a result, the mounting part 9 is particularly prone to flash shorting after current interruption.
The hot gas near the corners of the tank is not blown directly onto the tank wall, but is gently exhausted.

Further, the exhaust cover 11 reduces the electric field strength around the fixed contact mounting portion 9.

Therefore, the withstand voltage characteristics between the fixed contact attachment part 9 and the tank wall after the current is cut off can be improved, and since the exhaust cover 11 only covers a part of the exhaust port A, most of the gas that has passed through the arc can be improved. The hot gas is quickly exhausted into a large space inside the tank.

Therefore, it is possible to provide a puffer-type gas breaker with good cooling, a small tank diameter, and excellent shutoff performance.

Further, the outer circumferential portion of the exhaust cover may be arranged outside the outer circumferential portion of the fixed contact mounting portion, as shown by reference numeral 12 in FIG.

Furthermore, as shown by reference numeral 13 in FIG. 5, the outer circumferential portion of the exhaust cover may be structured such that it extends from the fixed contact mounting portion 9 in the direction of the conductors on the movable side and the fixed contact side.

Also, as an exhaust cover, reference numerals 14 and 15 in FIG.
It may also have a circular cross section as shown in .

Furthermore, the exhaust cover and the fixed contact mounting portion may be integrally constructed.

As explained above, according to the present invention, the outer periphery of the fixed contact mounting part also serves as a shield, and the gas flow is changed so that the exhaust gas that goes around the fixed contact mounting part is not blown directly onto the tank wall. Since an exhaust cover is provided for this purpose, a buffer type gas breaker with excellent breaking performance can be provided.

[Brief explanation of drawings]

Fig. 1 is a sectional view showing a conventional example, Fig. 2 is a sectional view showing an example of electric field improvement prior to the present invention, Figs. 3, 4, 5,
6 and 7 are cross-sectional views showing different embodiments of the present invention.

Claims (5)

[Scope of utility model registration request] (1) The arc-extinguishing gas in the movable cylinder is compressed by the breaking operation of the movable contact, and the compressed gas is sprayed onto the arc generated between the movable contact and the fixed contact, and the compressed gas passing through the arc from an exhaust port provided on the side of the mounting part of a cylindrical member that blocks the fixed contact from moving straight in the central axis direction from the mounting part and holds the fixed current-carrying contact outside of the fixed arc contact. In a buffer type gas breaker configured to discharge directly into a tank, one side is fixed to the outer edge of the mounting part of the fixed contact, and the other side is arranged so as to protrude further toward the movable contact than the mounting part. Then, an exhaust cover having a circular or part-circle cross-sectional shape at the tip facing the exhaust port side of the fixed contact is attached from the outside, and a part of the exhaust port facing the mounting part is covered from the outside to prevent an arc. 1. A buffer type gas breaker, characterized in that the passing gas causes a backflow so that the gas flow near the base of the mounting portion does not flow toward the tank wall. (2) The exhaust cover has an outer circumferential portion disposed outside the outer circumferential portion of the mounting portion.
Buffer type gas breaker described in section 1). (3) The exhaust cover has a structure in which the outer circumferential portion extends from the fixed contact mounting portion in the direction of the conductors on the movable side and the fixed contact side. Buffer type gas breaker as described in ). (4) The buffer type gas breaker according to claim (1), wherein the exhaust cover forms an integral structure with the fixed contact mounting portion. (5) In practical use, the exhaust cover is arranged so that the distance between its movable contact side tip and the fixed contact mounting portion is 1/20 or more of the distance from the central axis to the outer circumference of the exhaust cover. A buffer type gas breaker according to claim (1) of the patent registration.