JPH02117042A - Buffer type gas breaker - Google Patents

Abstract

PURPOSE:To reduce the damage of an exhaust port and a flow guide from a by leading hot gas flow into a buffer chamber from the first-stage exhaust port in the early process of breaking action, blocking the exhaust port in the later process of breaking action, and thereby exhausting hot gas flow to the environment out of the buffer chamber via the second-stage exhaust port. CONSTITUTION:Exhaust ports 5b and 5c are provided in two steps on the wall surface of a hollow actuating rod 5 driving a buffer chamber 6. And the exhaust port 5b at the first step on the side of a movable arc contact element 8 is communicated with the inside of a buffer chamber 11 in the early stage of breaking action the range of which roughly corresponds to the value of 0 to 40% of the whole stroke while the exhaust port 5c at the second step on the side far from the contact element 8 is blocked by the inner wall of a buffer piston 7. On the other hand, the exhaust port 5b at the first step is blocked by the inner wall of the buffer piston 7 in the later stage of breaking action the rang of which roughly corresponds to the value equal to or more than 60% of the whole stroke while the exhaust port 5c at the second step is communicated with the environmental space out of the buffer chamber 11. This constitution enables the damage of the exhaust ports 5b and 5c and a flow guide 12 to be reduced.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to gas circuit breakers used in power system substations or switchyards, and particularly relates to fixed and movable gas circuit breakers. In a buffer type gas circuit breaker, the thermal energy of the arc generated between the arc contacts is sent into the buffer chamber from the exhaust port 1 provided in the hollow operating rod to increase the pressure rise in the buffer chamber. This relates to technology for preventing damage to installed exhaust ports and flow guides and improving reliability of circuit breakers.

(Prior Art) As the capacity of power transmission systems increases, the breaking capacity of circuit breakers used in substations and switchyards increases, and high reliability is required. In order to improve the reliability of circuit breakers, it is important to reduce the number of parts and simplify the structure. For this purpose, it is necessary to reduce the number of breaking points of the circuit breaker by increasing the breaking capacity per one focal point of the circuit breaker.

Conventionally, in power transmission voltage systems of 168 KV or higher, so-called pan-foot type gas circuit breakers have been used to extinguish the arc generated between contacts by spraying gas to achieve the above-mentioned improvement in breaking capacity. There is.

This buffer type 1 gas circuit breaker has a fixed contact and a movable contact that can be moved toward and away from each other in a container filled with insulating and arc-extinguishing gas, and a buffer piston fixed to the back side of the movable contact. By compressing the buffer chamber, which consists of a buffer cylinder to which a movable contact is attached and which is driven by a hollow operating rod, the gas in the buffer chamber is compressed and guided to the movable contact side, and the gas controlled by an insulated nozzle is This is a circuit breaker configured to spray the arc generated between the fixed and movable arc contacts during the circuit breaker's breaking operation to cool and extinguish the arc.

This buffer type gas circuit breaker has a simple structure of the circuit breaker and has excellent insulation and arc extinguishing performance due to the enclosed insulating and arc extinguishing gas such as SF6 gas. Also,
In closed gas switchyards, where the entire substation equipment is insulated with insulating and arc-extinguishing gas such as SFa gas, the insulation and
It is possible to coordinate insulation between the circuit breaker and other equipment using arc-extinguishing gas, and it is also efficient in terms of equipment placement.
Especially widely used.

(Problem to be solved by the invention) By the way, the first possible method to increase the capacity of the buffer type gas circuit breaker as described above is to improve the opening speed or increase the capacity of the buffer cylinder. This is a method of increasing the pressure inside the buffer cylinder.

However, when these methods are adopted, not only the dimensions of the arc extinguishing chamber become large, but also a large drive device is required, which poses a major economical obstacle in manufacturing and operating the circuit breaker.

As a method for efficiently increasing the gas pressure in the buffer chamber without causing the above-mentioned economic disadvantages, a method using arc thermal energy has been proposed. It has been recognized that by skillfully utilizing thermal energy, it is possible to increase the pressure of the gas in the buff 1 chamber, spray extremely high-speed and powerful gas onto the arc, and improve the interrupting performance.

Roughly speaking, this is an example in which a two-stage communication hole is provided as an exhaust port on the operating rod in order to suppress gas pressure fluctuations at the initial stage of shutoff operation (
JP-A-62-17918) exists.

However, as described above, even if the method of utilizing the thermal energy of the arc is applied, as a result of the exhaust port provided on the operating rod being close to the arc, the exhaust port is damaged by the arc and the hot gas flow, and is shut off. This may affect the performance and reduce the reliability of the circuit breaker.

Further, although a flow guide for controlling the flow of hot gas is generally installed near the exhaust port, this flow guide is also easily damaged by the arc and the hot gas flow.

The present invention was proposed in order to solve the problems of the prior art as described above, and its purpose is to send the thermal energy of the arc into the buffer chamber through the exhaust port provided in the hollow operating rod. In a buffer type gas circuit breaker that increases the pressure rise in a chamber, damage to the exhaust port provided on the operating rod can be prevented.Furthermore, if a flow guide is installed near the exhaust port of the operating rod, damage to this flow guide can be prevented. It is an object of the present invention to provide a highly reliable buffer type gas circuit breaker that can prevent

[Structure of the Invention] (Means for Solving the Problems) The buffer type gas circuit breaker of the present invention is provided with a two-stage exhaust port on the wall surface of a hollow operating rod that drives a buffer cylinder, and has a total stroke of approximately 0 to At the beginning of the interruption operation in the range of 40%, the first stage exhaust port on the side of the movable arc contact communicates with the buffer chamber, and the second stage exhaust port on the side far from the movable arc contact communicates with the buffer piston. In the latter stage of the shutoff operation, which is approximately 60% or more of the total stroke, the first-stage exhaust port is closed by the inner wall of the buffer piston, and the second-stage exhaust port is closed by the surrounding area and space outside the buffer chamber. A distinctive feature of the structure is that it is placed so that it communicates with the

(Function) According to the present invention having the above configuration, at the initial stage of the shutoff operation, the first stage exhaust port opens into the buffer chamber, and the second stage exhaust port opens into the buffer chamber.
Since the exhaust port in the first stage is closed, the arc and the hot gas heated by the arc are introduced into the buffer chamber through the first stage exhaust port, and the pressure in the buffer chamber increases. In this case, the thermal energy of the arc is not very high, so the first stage exhaust port is hardly damaged. On the other hand, the second-stage exhaust port is closed, so there is little risk of it being affected.

In the latter half of the shutoff operation, the first stage exhaust port is closed and the second stage exhaust port opens outside the buffer chamber, so that the arc and the hot gas heated by the arc pass through the hollow part of the operating rod. and flows to the second stage exhaust port. At this stage, the thermal energy of the arc is increasing, but 1
The exhaust ports in the third stage are closed, so there is little risk of them being affected. On the other hand, since the second stage exhaust port is located far from the arc, it is less affected by the hot gas flow and suffers very little damage.

Further, when a flow guide for controlling the flow of gas is provided near the second-stage exhaust port, the influence of the hot gas flow on the flow guide can be reduced, so that damage to the flow guide can be reduced.

Roughly speaking, it is more effective if the distance between the first and second stage exhaust ports is approximately 20% of the total stroke.

In addition, if the opening area of the second stage exhaust port is made 1.3 times or more larger than the opening area of the first stage exhaust port, hot gas from the second stage exhaust port in the latter half of the shutoff operation can be reduced. The flow can be made smoother and hot gas can be efficiently discharged.

(Embodiment) As explained above, one embodiment of the buffer type gas circuit breaker according to the present invention will be specifically described with reference to FIGS. 1 to 3. Here, FIG. 1 shows the state of the arc extinguishing chamber in the early stage of the shutoff operation, and FIG. 2 shows the state of the arc extinguishing chamber in the latter half of the shutoff operation. Furthermore, FIG. 3 shows the amount of wear on the flow guide depending on the opening area ratio of the first-stage exhaust port and the second-stage exhaust port.

First, as shown in FIGS. 1 and 2, the interior of the arc extinguishing chamber is roughly divided into a fixed contact section 1 and a movable contact section 2. In the fixed contact portion 1, a fixed arc contact 4 is arranged at the center, and fixed current-carrying contacts 3 are arranged coaxially around the fixed arc contact 4. In the movable contact section 2 which can be moved into and out of contact with the fixed contact section 1 , a buffer cylinder 6 is arranged around a hollow operating rod 5 and is fixed to the operating rod 5 . At the tip of the operating rod 5, a movable arc contact 8 is arranged on the inside, and a movable current-carrying contact 9 is arranged coaxially on the outside thereof, both of which are fixed to the operating rod 5. An insulating nozzle 10 is disposed between the movable arc contact 8 and the movable energizing contact 9 so as to cover the outer periphery and the tip of the movable arc contact 8, and is fixed to the operating rod 5. The buffer cylinder 6 of the movable contact 2 forms a buffer chamber 11 together with an end 7a of a buffer piston 7 fixed to an insulator on the drive device side (lower in the figure), not shown.

The operating rod 5 of the movable contact portion 2 is connected to the hollow portion 5a.
It has two stages of exhaust ports 5b and 5c that communicate between the inside and the outside. In this case, at the beginning of the shutoff operation in the range of approximately 0 to 40% of the total stroke, as shown in FIG.
The exhaust port 5b of the second stage communicates with the inside of the buffer chamber 11, and the exhaust port 5C of the second stage is closed by a barrier 7b formed by extending the inner wall of the end 7a of the buffer piston 7 toward the back side. It has become. In addition, in the latter half of the shutoff operation in a range of approximately 60% or more of the total stroke, the first stage exhaust port 5b is blocked by the barrier 7b of the buffer piston 7, and at the same time the second stage The exhaust port 5C is configured to communicate with the surrounding gas space outside the buffer chamber 11. Furthermore, a flow guide 12 for controlling the flow of gas is provided near the second stage exhaust port 5G inside the operating rod 5.

In addition, the distance between the first and second stage exhaust ports 5b and 5C is,
The stroke is approximately 20% of the total stroke. On the other hand, the opening area of the second-stage exhaust port 5C is approximately 1.3 times or more larger than the opening area of the first-stage exhaust port 5b. As shown in FIG.
As a result of investigating the wear amount of 2, if the opening area of the second stage exhaust port is smaller than approximately 1.3 times the opening area of the first stage exhaust port 5b, as the opening area ratio increases, This is because it has been confirmed that when the amount of wear on the flow guide decreases and the opening area ratio becomes 1.3 times or more, the amount of wear on the flow guide tends to stabilize at an extremely low value.

The operation of this embodiment having the above configuration will be explained below.

That is, when the buffer type gas circuit breaker of this embodiment receives a shutoff command in the closed state, the shutoff operation starts and the operating rod 5 moves toward the drive device (not shown) (downward in the figure).

In the initial stage of the breaking operation, as shown in FIG.
．． An arc 13 occurs between 8 and 8. At this stage, the arc 13 is generating a large amount of heat, and this heat causes
The gas around the arc 13 becomes an expansion flow 14a ejected from the tip of the insulating nozzle 10 toward the fixed arc contact 4, and an expansion flow 14b passing through the hollow portion 5a of the operating rod 5. However, at this stage, the insulating nozzle 10 is not yet fully open and therefore has no ability to interrupt the arc 13. In addition, in the state shown in FIG. 1, the first stage exhaust port 5b of the operating rod 5 is still connected to the end 7a of the buffer piston 7.
This exhaust port 5b does not pass through the buffer chamber 1.
It communicates with 1. On the other hand, the second stage exhaust port 5c is closed by the barrier 7b of the buffer piston 7. Roughly speaking, at the beginning of such a shutoff operation, the buffer chamber 1
1 is still in its initial stage, and the pressure increase in buffs 1 to 11 due to this mechanical action is still small. It rapidly flows into the buffer chamber 11 through the first stage exhaust port 5b. In this case, the expanding flow 14
Since the flow of b is very large, it effectively imparts heat to the gas in the buffs 1 to 11. Since this is added to the original compression operation of the buff 1 piston 7 and the buffer cylinder 6, the pressure within the buffer chamber 11 increases synergistically. That is, in this embodiment, compared to a conventional buffer type gas circuit breaker that simply compresses the buffer chamber 11, the pressure can be increased more roughly by the amount of the expanded flow 14b flowing into the buffer chamber 11 from the exhaust port 5b. Therefore, even with a small drive device that is capable of extinguishing an arc, a buffer type gas circuit breaker with higher interrupting performance than conventional circuit breakers can be realized.

In addition, at the initial stage of the breaking operation as described above, the arc 1
Since the thermal energy of 3 is still small, the first stage exhaust port 5
Even if the expanded flow 14b flows into the exhaust port 5b, this exhaust port 5b is hardly damaged. Further, since the second stage exhaust port 5C is closed, the second stage exhaust port 5C and the flow guide 12 are hardly affected.

In the latter half of the shutoff operation, as shown in FIG. 2, the first stage exhaust port 5b of the operating rod 5 passes through the end 7a of the buffer piston 7 and is blocked by the barrier 7b of the buffer piston 7, while At almost the same time, the second stage exhaust port 5
C communicates with the surrounding space outside the buffer chamber 11. Therefore, the expanded gas flow 14b from the arc 13 is exhausted from the hollow portion 5a of the operating rod 5 to the surrounding space outside the buffer chamber 11 via the second stage exhaust port 5C. At this stage,
The thermal energy of arc 13 is increasing rapidly,
Since the first stage exhaust port 5b near the arc 13 is closed, it is hardly affected.

Furthermore, the second-stage exhaust port 5C and the flow guide 12, which serve as a path for the expansion flow 14b, are located far from the arc 13 and are less affected by the expansion flow 14b, so that damage thereto is extremely small. In addition, the opening area of the second stage exhaust port 5c is approximately 1.
Since it is three times or more larger, the flow of hot gas from the second-stage exhaust port in the latter half of the shutoff operation can be made smooth, and the hot gas can be efficiently discharged. As is clear from the graph of FIG. 3, by setting the opening area ratio to 1.3 times or more, the amount of wear and tear on the flow guide 12 can be minimized.

[Effects of the Invention] As explained above, in the present invention, by separately providing the two-stage exhaust ports on the operating rod, at the beginning of the interrupting operation when the thermal energy of the arc is low, the first-stage exhaust port The hot gas flow is guided into the buffer chamber by the opening of the opening, and in addition to mechanical compression, the pressure inside the buffer chamber can be efficiently increased.In addition, in the latter stage of the interruption operation when the thermal energy of the arc is increased, the first stage near the arc The eye exhaust port can be occluded and the hot gas flow can be exhausted to the ambient space outside the buffer chamber through a second stage of exhaust ports remote from the arc.

That is, according to the present invention, during the latter half of the interrupting operation when arc energy is high, hot gas is discharged through the second stage exhaust port far from the arc without directly affecting the first stage exhaust port near the arc. Since the flow can be exhausted, damage to the operating rod's exhaust port can be significantly reduced compared to conventional methods.Furthermore, if a flow guide is installed near the operating rod's exhaust port, damage to this flow guide can also be prevented. We can provide a highly reliable buffer type gas circuit breaker.

[Brief explanation of drawings]

Figures 1 and 2 are cross-sectional views of an arc extinguishing chamber showing an embodiment of the buffer type gas circuit breaker according to the present invention, with Figure 1 showing the early stage of the circuit breaker and Figure 2 showing the latter stage of the circuit breaker. . FIG. 3 is a graph showing the amount of wear on the flow guide with respect to the opening area ratio of the first-stage exhaust port and the second-stage exhaust port. 1... Fixed contact part, 2... Movable contact part, 3...
・Fixed current-carrying contact, 4...Fixed arc contact, 5...
・Operation rod, 5a...Hollow part, 5b...1
Stage exhaust port, 5C...Second stage exhaust port, 6...Buffer cylinder, 7...Buffer piston, 7a...
- End of buffer piston, 7b... Barrier of buffer piston, 8... Movable arc contact, 9... Movable energizing contact, 1o... Insulating nozzle, 11... Buffer chamber, 12. ...Flow guide, 13...Arc, 14
a, 14b... Expansion flow.

Claims (1)

[Claims] A container filled with insulating/arc-extinguishing gas includes a fixed contact and a movable contact that can be moved toward and away from each other, and a buffer piston fixed to the back side of the movable contact and a movable contact. the child is attached,
By compressing the buffer chamber consisting of a buffer cylinder driven by a hollow operating rod, the gas in the buffer chamber is compressed and guided to the movable contact side, and the gas controlled by the insulating nozzle is used to shut off the circuit breaker. In a buffer type gas circuit breaker configured to cool and extinguish an arc generated between a fixed and movable arc contact during operation, a hollow operating rod that drives the buffer cylinder is provided. There are two exhaust ports on the wall, one on the movable arc contact side.
The exhaust port in the stage communicates the hollow part of the operating rod with the buffer chamber at the initial stage of the shutoff operation, which is approximately 0 to 40% of the total stroke, and is located in a range that is approximately 60% or more of the total stroke. In the latter half of the cutoff operation, the second stage exhaust port, which is located so as to be closed by the inner wall of the buffer piston and is far from the movable arc contact, is
In the early stage of the shutoff operation in the range of approximately 0 to 40% of the total stroke, the hollow part of the operating rod is closed by the inner wall of the buffer piston, and in the latter half of the shutoff operation in the range of approximately 60% or more of the total stroke. A buffer type gas circuit breaker characterized in that it is arranged so as to communicate with the surrounding space outside the buffer room.