JPS61206126A - Buffer type gas breaker - 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 [Field of Application of the Invention] The present invention relates to a buffer type gas circuit breaker, and particularly to a nozzle shape of a gas circuit breaker suitable for improving circuit breaker performance.

[Background of the invention]

The nozzle shape of the conventional buffer type gas circuit breaker is
As described in Japanese Patent No. 1-81974, it is disclosed that a gas passage is provided that communicates from the upstream part to the downstream part of the nozzle, and that this gas passage is provided with a valve mechanism that opens at a pressure equal to or higher than a set pressure.

Although this invention has the effect of suppressing an excessive pressure rise in the upstream portion of the nozzle when the current is cut off, the provision of a valve mechanism complicates the structure and reduces reliability. Further, Japanese Utility Model Application Publication No. 56-130246 discloses an example in which a gas passage communicating between the upstream and downstream parts of the nozzle is provided and the gas passage insulator is operated by an elastic body. Although this also has the effect of blowing out arc-extinguishing gas to the downstream part of the nozzle and increasing the arc-extinguishing ability, since it is operated using an elastic body, the structure becomes complicated and reliability decreases. In addition, multiple gas passages are provided in the axial direction, which increases the total cross-sectional area of the gas passages, which increases the amount of gas exhausted through the gas passages. There is a problem in that it is not possible to spray the arc sufficiently. It is known to provide a gas passage communicating the upstream and downstream parts of the nozzle. As a result of recent research, it has been found that the shape of the gas passage, its angle from the upstream part to the downstream part of the nozzle, etc., are extremely important, but the above-mentioned publication did not give any consideration to these matters.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a buffer type gas circuit breaker equipped with a nozzle that can recover insulation between electrodes immediately after interruption of a large current.

[Summary of the invention]

As a method to hasten the insulation recovery between the electrodes immediately after interrupting a large current in a buffer-type gas circuit breaker, there are two methods: (1) prompt removal of high-temperature gas around the electrodes, (2) increasing the gas density around the tip of the fixed electrode. (3) The effect of (2) can be started after a certain position where the fixed electrode is relatively removed from the nozzle throat portion. Of these (1)
(2) is taken for granted.

As a result of experiments, it was found that (3) has a large effect on improving insulation recovery, and as a specific nozzle structure that produces this effect, a bypass hole is provided that communicates the upstream and downstream parts of the nozzle, and the bypass hole is disconnected. The area is small at the upstream part of the nozzle,
It is constructed in the shape of, for example, a cone so that it becomes larger in the downstream portion.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIG. 1st
The figure shows the buffer type gas circuit breaker in the middle of shutting off, and when the circuit breaker is in the closed state, the fixed electrode 1 is located at the bottom in the figure, is in contact with the movable electrode 2, and is in a state where it can be energized. The interrupting operation is performed by the puffer cylinder 3 and the movable electrode 2 fixed to the puffer cylinder 3. Insulated nozzle 4. This is done by driving the nozzle holder 5, electrode cover 6, etc., together, downward in the figure by an operation mechanism (not shown). Fixed electrode 1 and movable electrode 2
When the circuit breaker opens, an arc 7 is generated between the two electrodes or in the energized parts around the fixed electrode 1 and the movable electrode 2 as shown in the figure. , when the puffer cylinder 3 moves downward in the figure, the main volume of the buffer chamber space formed by the space with the fixed piston 8 is reduced, and the gas in this space is arced as shown by the arrow in Figure 1. The arc is cooled,
The arc is extinguished at the zero point of the current. The arc-extinguishing gas that comes into contact with the arc dissociates and ionizes and becomes conductive, and after the current is cut off, the temperature rapidly drops and the gas recovers to an insulating gas, but the gas is still at a considerable temperature due to the arc heat. After the current is cut off, the gas has a lower dielectric strength than when no arc occurs. After the arc is extinguished, the power supply voltage generated between the fixed electrode 1 and the movable electrode 2 increases toward its recovery voltage, but if the insulation recovery between the circuit breaker poles is delayed, dielectric breakdown occurs between the poles. In the embodiment shown in FIG. 1, the insulating nozzle 4 is provided with a bypass hole 10, which has a one-conical shape, for example, and is narrow at the upstream part of the nozzle and widen at the downstream part of the nozzle. As shown in FIG. 2, a plurality of bypass holes are formed radially from the center of the nozzle, and the number of bypass holes is, for example, four to eight.

The bypass hole has an effect both during arc generation and after arc extinguishment. In other words, the arc generated when a large current is interrupted will spread within the throat section 11 of the nozzle, and depending on the magnitude of the current, the arc will be The nozzle throat becomes full,
This creates a nozzle blockage phenomenon that prevents gas from escaping through the throat. At this time, the pressure in the buffer increases rapidly due to obstruction of gas outflow, high temperature of gas, evaporation of material in nozzle 4, etc., and high temperature gas stagnates upstream of the nozzle. In addition, the cross-sectional area of the bypass hole increases from the upstream part to the downstream part, so the high-temperature gas becomes high-speed in the bypass hole and is exhausted as shown by the arrow in Figure 1, so the high-temperature gas nozzle There is less stagnation upstream, which speeds up insulation recovery after arc extinction.

Next, the function of the bypass hole after the arc is extinguished will be explained. The dielectric strength is proportional to P' when the gas pressure is P.The higher the gas pressure, that is, the higher the gas density, the higher the dielectric strength.After the current is cut off, the arc-extinguishing gas is exhausted through the nozzle throat. However, since the gas flows at high speed, a decrease in gas density around the fixed electrode may be a factor in decreasing insulation recovery.

However, in FIG. 1, the nozzle has a bypass hole 10 which is narrow at the upstream portion and widened at the downstream portion.

The gas is accelerated through the bypass hole and blown out toward the fixed electrode, making it possible to increase the gas pressure around the fixed electrode, which has the effect of extremely improving insulation recovery. FIGS. 3 and 4 are diagrams illustrating preferred blowing angles of the bypass holes according to the present invention.

The widening angle of the bypass hole with respect to the nozzle radial direction, where the side closer to the nozzle throat is θ (Fig. 3) and the far side is 02 (Fig. 4). In Fig. 3, Sl is the nozzle throat. As a result of 6 experiments, S2 is the cross-sectional area of , and S2 is the area of the downstream flow path formed by the fixed electrode and the downstream space of the nozzle.
It has been found that sufficient insulation recovery can be obtained after relative movement of the fixed electrode to a position where is greater than 81. Therefore, if θ1 shown in FIG. 3 is defined as the minimum angle θ toward the center of the tip of the fixed electrode when the fixed electrode moves relatively to the position S, :Si, then the gas can be effectively It can be seen that high insulation recovery can be obtained. Further, 02 in FIG. 4 indicates that the angle toward the outer periphery of the tip of the fixed electrode when the fixed electrode makes a relative flow stroke at the time of completion of interruption is the maximum angle θ. θ1. θ2 is a range with the relationship θ2>θ1, and θ
1≧θ,.

Some variation is allowed within the range θ2≦θ. By doing this, during the cutoff operation, the fixed electrode is S,=S1
From the position until the full stroke, gas is blown at high speed toward the fixed electrode through the bypass hole 1o, increasing the gas density around the tip of the fixed electrode. According to this embodiment, firstly, when the current is cut off, high-temperature gas on the upstream side of the nozzle is exhausted through the bypass hole, which prevents stagnation of high-temperature gas on the upstream side of the nozzle. This has the effect of helping speed up insulation recovery after arc extinction. Second, after the arc extinguishes, the bypass hole widens in the downstream part of the nozzle, so that the fixed electrode covers almost all the stroke positions of the interruptable region during the movement of the interrupting operation.

Since the gas is sprayed around the tip of the fixed electrode through the bypass hole, it is possible to provide a break with excellent recovery of interelectrode insulation after current cutoff.

Different embodiments of the invention are shown in FIGS. 5 and 6.

Fig. 5 shows a nozzle that combines the bypass holes shown in Figs. 1 to 4 and a bypass hole 12 with a constant cross-sectional area, and Fig. 6 shows the bypass holes shown in Figs. 1 to 4 and a nozzle downstream of the nozzle. Bypass hole 13 whose cross-sectional area slightly increases toward the end
This is a nozzle that combines the following.

Note that the locations where the central axes of these newly added bypass holes intersect with the tip of the fixed electrode satisfy the relationship 81 to S. Even in different embodiments, the effects described in FIGS. 1 to 4 can be obtained, and in this case, a bypass hole is added that allows gas to be sprayed concentratedly at the tip of the fixed electrode with a short stroke, so in particular, When the arc time is short, the polarity interruption can be improved.

〔Effect of the invention〕

According to the present invention, it is possible to provide a buffer-type gas circuit breaker with excellent inter-electrode insulation recovery after current interruption over the entire area.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view of the interrupting part of the present invention, Fig. 2, and Fig. 3 IjA.
, FIG. 4 is a sectional view of the nozzle, and FIGS. 5 and 6 are sectional views of the nozzle showing different embodiments. DESCRIPTION OF SYMBOLS 1... Fixed electrode, 2... Movable electrode, 3... Puffer cylinder, 4... Nozzle, 10, 12, 13...
Bypass hole.

Claims (1)

[Scope of Claims] 1. A puffer chamber is formed by a separable fixed electrode and a movable electrode, a puffer cylinder, and a fixed piston, and the gas in the puffer chamber is compressed during a shutoff operation to create a high-pressure extinguisher. A puffer-type gas circuit breaker in which arc gas is guided by a nozzle and sprayed onto the arc between the fixed electrode and the movable electrode, and is provided with a bypass hole that communicates an upstream part and a downstream part of the nozzle, wherein the bypass hole is . A puffer-type gas circuit breaker, characterized in that the nozzle is configured to widen in a conical shape from an upstream portion toward a downstream portion. 2. In claim 1, at a position where, among the widening angles of the bypass hole with respect to the radial direction of the nozzle, the one closer to the nozzle throat intersects with the center of the tip of the fixed electrode, The angle is equal to or greater than the angle at which the downstream flow path area formed by the fixed electrode and the downstream space of the nozzle is approximately equal to the cross-sectional area of the nozzle throat; A puffer-type gas circuit breaker characterized in that of the spread angles, the one farther from the nozzle throat is equal to or smaller than the angle that intersects with the outer periphery of the tip of the fixed electrode that is fully stroked in the breaking operation. 3. In claim 1, a bypass hole is provided in which the cross-sectional area of the bypass hole is constant and the width of the bypass hole is small from the upstream part of the nozzle to the downstream part, and the central axis of the bypass hole is aligned with the downstream flow. A buffer type gas circuit breaker, characterized in that the path area is directed toward the center of the tip of the fixed electrode where the cross-sectional area of the nozzle throat section is approximately equal to the cross-sectional area of the nozzle throat section.