JP2644737B2 - Patch type gas circuit breaker - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a gas circuit breaker, and more particularly to a nozzle structure suitable for a high-voltage large-capacity gas circuit breaker.

[Conventional technology]

In order to increase the high voltage and the capacity of the gas circuit breaker, the specifications of the insulating nozzle have a great influence. In particular, in an insulating nozzle of a circuit breaker that interrupts a large current, it is necessary to effectively cool an arc generated between electrodes.

FIG. 4 and FIG. 5 are longitudinal sectional views of a shut-off portion of a typical conventional gas-type circuit breaker. That is, focusing on the upstream shape of the throat portion of the insulating nozzle 1, FIG. 4 is classified into a radial spray type and FIG. 5 is classified into an axial spray type. In the case of radial spraying, the spraying to the fixed contact 2 and the movable contact 3 is almost the same, but in the case of axial blowing, the spraying toward the fixed contact 2 is performed. Be strengthened. The ratio varies depending on the inclination angle on the upstream side of the throat. According to the experimental results of the inventors, it is important to improve the withstand voltage in the vicinity of the tip B of the fixed contact 2 when cutting off a large current, and the axial spray nozzle shown in FIG. It is desirable to use.

In order to improve the withstand voltage, it is also important to keep the electric field of each part as low as possible. The disadvantages of axial spray nozzles are
This is because the creeping electric field intensity at point A on the upstream end of the nozzle throat is high. Therefore, when a high voltage is applied between the electrodes, the probability of dielectric breakdown from the fixed contact 2 to the buffer cylinder 4 through the inner surface of the nozzle from the point A of the insulating nozzle 1 increases.

Table 1 qualitatively shows the above description. That is, the radial spray type has a higher withstand voltage because the electric field is lower at the point A at the upstream end of the nozzle throat than in the axial spray.

[Problems to be solved by the invention]

However, the radial spray type has a lower withstand voltage since the pressure at the fixed contact tip B is lower than that of the axial spray type. Therefore, in the prior art, the nozzle structure having a high withstand voltage at the point A has a low withstand voltage at the point B, and the nozzle structure having a high withstand voltage at the point B has a drawback that the withstand voltage at the point A is low.

JP-A-55-155430, JP-A-56-118229, JP-A-56-126224, etc. are those aimed at improving the creepage withstand voltage on the upstream side of the nozzle throat. It is intended to increase the creepage distance of the inner surface on the throat upstream side of the nozzle 1 to improve the creepage withstand voltage,
The above drawbacks are not considered.

An object of the present invention is to provide a puffer-type gas circuit breaker suitable for high-voltage and large-current interruption in which the withstand voltage between electrodes is improved by using an axial spray type insulated nozzle in which the creeping electric field at point A is reduced. Is to do.

[Means for solving the problem]

In order to achieve the above object, a puffer type gas circuit breaker according to the present invention comprises a fixed contactor and a movable contactor which can be brought into contact with and separated from each other during operation of the circuit breaker; In a puffer type gas circuit breaker provided with an insulating nozzle for spraying a generating portion and a compressed arc-extinguishing gas to an arc between poles generated as the movable contact and the fixed contact are separated, the movable contact A flow path for arc-extinguishing gas is formed between the flow guide provided on the outer peripheral side of the insulating nozzle and the insulating nozzle, and a throat portion of the insulating nozzle is provided on the downstream side of the flow guide. The inner surface shape of the insulating nozzle between the flow guide portion and the throat portion forms an acute angle with the nozzle central axis so that the area gradually decreases from the upstream side to the downstream side. Portion substantially parallel to the inner surface portion and the central axis of said insulating nozzle, it is characterized in that has a substantially right-angled inner surface portion and the central axis direction of the insulating nozzle.

[Action]

The air flow on the upstream side of the nozzle is substantially determined by the inner surface 13 and has an effect similar to that of the axial spray type, increasing the pressure at the fixed contact tip B and improving the withstand voltage. on the other hand,
Since the electric field at point A has an inner surface 15 substantially perpendicular to the nozzle center axis, the same effect as in the radial spray type is produced, and the creeping electric field is reduced.

〔Example〕

Hereinafter, an embodiment of the present invention and dimensional parameters and withstand voltage will be described with reference to FIGS. 1 to 3. Reference numeral 1 denotes an insulating nozzle, an inner surface 13 forming an acute angle with the nozzle central axis, an inner surface 14 substantially parallel to the nozzle central axis, and a substantially perpendicular direction to the central axis direction so that the upstream area of the nozzle throat portion S gradually decreases. The throat portion S has a divergent portion 18 downstream from the throat portion S. Reference numeral 2 denotes a fixed contact and reference numeral 3 denotes a movable contact that comes into contact with and separates from the fixed contact 2. Reference numeral 6 denotes a flow guide provided so as to surround the periphery of the movable contact 3, and reference numeral 4 denotes a buffer cylinder, which is connected to an operating device (not shown). The buffer chamber pressure generating section 5 is formed between the fixed piston 16 and the fixed piston 16. Reference numeral 7 denotes a nozzle holder for fixing the insulating nozzle 1 to the buffer cylinder 4. The movable contact 3 and the flow guide 6 are attached to the center of the buffer cylinder 4, and the gas flow from the pressure generating section 5 is guided to the flow path formed by the insulating nozzle 1 and the flow guide 6, There is an air supply path indicated by an arrow.

A part of the interruption operation in the structure of the present invention thus constituted will be described in detail with reference to FIG.

When a cutoff command is received, an operating device (not shown) is driven, and the buffer cylinder 4 moves to the left in the figure. As a result, while the arc-extinguishing gas in the buffer chamber 5 is compressed and the pressure is increased, the opening operation of the fixed contact 2 and the movable contact 3 is performed. From the vicinity of the tip of the fixed contact 2 to the nozzle throat S
In the process until the gas exits, most of the compressed gas 5 in the buffer chamber flows through the gas passage toward the center of the buffer cylinder 4 via the center hole of the mover 3.

When the shut-off step further proceeds, the position becomes a relationship as shown in FIG.
Is also formed.

At this time, since the air flow on the upstream side of the nozzle is substantially determined by the inner surface 13, the gas blowing to the fixed contact 2 has the same effect as the axial blowing shown in FIG. The pressure at the tip B increases, and the withstand voltage can be improved. On the other hand, the electric field at point A has an inner surface 15 substantially perpendicular to the central axis of the nozzle, so that an effect similar to that of the radial spray type shown in FIG. 4 is produced, and the creeping electric field can be reduced.
Accordingly, the withstand voltage reaching the inner surfaces 14, 13 via the inner surface 15 is significantly improved.

Here, FIG. 2 and FIG. 3 show the results of studies on the dimensions and withstand voltage of the inner surfaces 13, 14, and 15.

FIG. 2 shows a detailed sectional view of a part of the insulating nozzle 1 according to the invention. An extension of the nozzle inner surface 13 and the upstream end of the nozzle throat S are shaped so as to be substantially the same point.

The upstream radius X and the downstream radius of the inner surface 13, that is, the inner surface
FIG. 3 shows the withstand voltage with the radius of 14 as R and R / X as a parameter. The withstand voltage at point A at the upstream end of the throat increases as R / X increases. This is because the larger the R / X, the wider the area where the creeping electric field is low. The withstand voltage at the stator tip B is substantially constant up to a certain value of R / X, but then decreases. R at that time is substantially equal to the outer radius of the flow guide 6. In FIG. 3, when the withstand voltage specified by the standard is indicated by a dashed line, the value of R / X is in the range of C, that is, R
It turns out that it is good to select / X at 40-80%.

Next, the relationship between the position of the intersection of the line segment extending in the nozzle center axis direction of the nozzle inner surface 13 and the line segment passing through the nozzle diameter of the throat S and parallel to the nozzle center axis and the position of the upstream end of the throat S The result of the examination will be described. First, when the intersection is located downstream from the upstream end of the throat S, the withstand voltage of the fixed contact tip B decreases. When the intersection is located downstream of the upstream end of the throat S, the withstand voltage of the fixed contact tip B hardly decreases.

According to the present embodiment, the withstand voltage at the inner surface of the insulating nozzle can be improved at the same time as the withstand voltage at the tip end of the stator can be improved.

Another embodiment of the present invention is shown in FIG. The shape of the divergent portion of the insulating nozzle 1 has irregularities 8, 9, 10, 11, and 12. (JP-A-60-26286, S.60.2.15).

The first concave and convex portions 8 and 9 provided in the nozzle divergent portion are formed on a tapered wall extending from the concave portion 8 to the convex portion 9 when the distal end portion of the fixed contact 2 is located relatively close to the nozzle throat portion. Upon collision, a gas flow is formed toward the center, that is, near the tip of the fixed contact 2, and increases the pressure in this portion where the electric field is high. When the blocking step further proceeds, the second uneven portions 10 and 11 provided in the nozzle divergent portion come near the tip of the fixed contact 2, and the same as when the fixed contact 2 is located in the first uneven portion. Thus, the pressure near the tip of the fixed contact 2 can be increased. Accordingly, by providing such a concavo-convex portion over substantially the entire length of the divergent portion of the nozzle, the pressure near the tip of the fixed contact 2 can be kept high, and the excessive dielectric strength between the poles can be improved. Can be.

〔The invention's effect〕

ADVANTAGE OF THE INVENTION According to this invention, the gas blowing to the fixed-contact tip part can be strengthened, and the creeping electric field of the throat upstream end part of an insulating nozzle can be aimed at, and the withstand voltage of a breaking part can be improved.

[Brief description of the drawings]

FIG. 1 is an explanatory view of an interrupting operation of an interrupting portion according to one embodiment of the present invention, FIG. 2 is a partial sectional view of an insulating nozzle of the present invention, FIG. 5 and FIG. 5 are cross-sectional views of a conventional example of a general blocking portion, and FIG. 6 is a cross-sectional view of a blocking portion of another embodiment of the present invention. DESCRIPTION OF SYMBOLS 1 ... Insulating nozzle, 2 ... Fixed contact, 3 ... Movable contact, 4 ... Buffer cylinder, 5 ... Buffer chamber, 6
…… Flow guide, 13,14,15 …… Nozzle upstream side inner surface, 16
... fixed piston.

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Osamu Koyanagi 4026 Kuji-cho, Hitachi, Japan Inside Hitachi, Ltd.Hitachi, Ltd.Hitachi Laboratory (72) Inventor Kunio Hirasawa 4026, Kuji-cho, Hitachi, Ltd.Hitachi, Hitachi, Ltd. In-house (72) Inventor Keisho Endo 4026 Kuji-cho, Hitachi City In-house Hitachi Research Laboratory, Hitachi Ltd. (56) References JP-A-51-67974 (JP, A) JP-A-59-74643 (JP, U.S.A.) ) Actually open 55-108635 (JP, U)

Claims (3)

(57) [Claims] A pressure generating section comprising a cylinder and a piston for compressing the arc-extinguishing gas together with the shut-off operation; In a puffer type gas circuit breaker provided with an insulating nozzle for blowing an arc between the movable contact and the fixed contact caused by the separation of the fixed contact, a flow guide provided on an outer peripheral side of the movable contact and the insulation A flow path of the arc-extinguishing gas is formed between the nozzle and the nozzle, and a throat portion of the insulating nozzle is provided on a downstream side of the flow guide, wherein the flow guide portion and the throat portion are provided. The inner surface shape of the insulating nozzle between the inner surface portion forming an acute angle with the nozzle central axis so that the area gradually decreases in order from the upstream side to the downstream side, and the inner surface substantially parallel to the central axis of the insulating nozzle. Moiety, puffer type gas circuit breaker characterized in that it has a substantially right-angled inner surface portion and the central axis direction of the insulating nozzle. 2. The insulating nozzle according to claim 1, wherein the radius of the inner surface of the insulating nozzle upstream of the insulating nozzle formed so that the area gradually decreases toward the throat portion is X, A puffer-type gas circuit breaker, wherein R / X is in a range of 40% or more and 80% or less, where R is a radius of an inner surface portion substantially parallel to a central axis. 3. The throat portion according to claim 1, wherein a divergent portion is formed on the downstream side of the throat portion, and the divergent portion has an uneven portion. Puffer type gas circuit breaker.