JP2557470B2 - Puffer type gas circuit breaker - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to a puffer type gas circuit breaker having an improved arc extinguishing chamber.

(Prior Art) A circuit breaker using SF ₆ gas as an arc extinguishing medium was developed in the United States in the 1955's. At that time, a two-pressure system was used in which high-pressure gas was always retained and was blown onto the arc. After that, a puffer type was devised that uses the driving force to open the contacts to compress the gas by the "bellows principle" to create and shut off high-pressure gas, and in the mid-1965's, a 70kV class product was commercialized. It was Today, it has become the majority of high voltage circuit breakers due to its excellent insulation performance and simplicity of construction.

In the puffer type gas circuit breaker, as shown in FIG. 4, the gas in the puffer cylinder is compressed only during the contact opening operation to generate a high pressure gas to obtain a breaking ability. Gas compression in the cylinder is performed by relative movement between the puffer piston and the puffer cylinder.

The gas pressure in the puffer cylinder is closely related to the shutoff performance. The arc is cooled by the gas stream. The cooling rate can be increased by increasing the pressure.
Therefore, it is necessary to increase this pressure to accelerate the recovery of the arc.

Since the puffer type compresses while blowing gas, in order to increase this pressure, it is necessary to increase the compression cross-sectional area and increase the compression efficiency. However, when the compression cross section is increased, the outer shape is increased and the circuit breaker is increased. Further, as the compression area increases, the reaction force received also increases, and the drive energy for opening the contact also increases.

In such a puffer type, it is known that a high temperature and high density arc occupies the nozzle and reduces the amount of ejected gas. This phenomenon is called nozzle clogging, but by reducing the gas flow at the peak value of the current and recovering the gas flow near the zero point of the current, the gas compression efficiency can be increased, It was getting attention. However, on the other hand, it has been found that a large risle diameter and a large amount of gas sprayed withstand a higher voltage. When the puffer type was first developed, no technology was established to withstand a high voltage with a small amount of gas, so this nozzle blockage cannot be used effectively, and it is considered difficult to increase the capacity. Was there.

After that, analysis technology such as electrolysis analysis and hot gas flow analysis, or improvement of gas flow measurement technology has enabled establishment of a technology that enables effective use of a small gas flow and improves voltage. As a result, it is possible to effectively compress by utilizing this nozzle blockage phenomenon.
It is possible to cut off 300kV-63kA with one breaking contact.
This breaking capacity reaches 14GVA, breaking capacity at 72kV-25kA 1
It is 10 times more than 3.5 GVA.

(Problems to be Solved by the Invention) However, as the capacity has increased, driving energy has increased, and an increase in mechanical stress has adversely affected the reliability of the device. Then, what was considered was to introduce the gas whose temperature was raised by being exposed to the arc into the puffer chamber and utilize it for increasing the pressure. The limit of this method is the self-extinguishing arc type. This is to use a pressure booster chamber instead of the puffer cylinder, take hot gas into the pressure booster chamber at the time of peak current to increase the pressure, and conversely, blow gas to the arc at the current zero point to shut off the gas. It was known to work effectively at high currents. However, the responsibilities of circuit breakers range from small current interruption to large current interruption. The self-extinguishing type was not effective for interrupting a small current, and it was necessary to use it together with the puffer type.

The hybrid puffer type shown in FIG. 5 was devised based on this idea. Even with the conventional puffer type, hot gas was introduced back into the puffer chamber by backflowing through the upstream gas flow path, but it did not work effectively because it was ejected when it approached the current zero point. On the other hand, in the hybrid puffer type, a hole is formed in the operating rod, and hot gas is introduced into the puffer chamber through this hole in the initial opening phase, and is mixed with the cold gas in the puffer chamber and sprayed, which is extremely effective. Target. Further, since the hole of the operation rod moves to the rear of the puffer piston to release the hot gas, the cooling effect can be enhanced.

However, in this method, since the hole of the operation rod passes through the inner surface of the puffer piston, sliding it may cause a metallic foreign substance, which may adversely affect the insulation performance. Therefore, measures are taken such as providing a gap between the puffer piston and the operating rod. However, there is a problem that gas loss is reduced and efficient compression cannot be performed.

The present invention has been made in view of the above problems, and an object thereof is to prevent generation of foreign matter by sliding from the hole of the operation rod and the inner circumference of the puffer piston in the hybrid puffer type. For this reason, in the present invention, the diameter of the inner peripheral portion of the puffer piston corresponding to the hole portion is increased so that the holes do not come into contact with each other. In addition, a Teflon member is attached to the inner peripheral portion of the piston and the outer peripheral portion of the operating rod for sliding movement.

[Structure of Invention]

(Means for Solving the Problems) In order to achieve the above object, in the present invention, a groove is provided in a portion corresponding to a communication hole of an operating rod, and the operating rod and the puffer piston are brought into contact with each other via a sliding member. There is.

(Operation) With this configuration, the hole of the operating rod does not move as a puffer piston, so it is possible to provide a puffer-type gas circuit breaker with excellent blocking performance that suppresses damage and the generation of foreign matter. it can.

(Example) The structure of the present invention will be described based on an example shown in FIG. The fixed arc electrode 1 is supported by a fixed portion (not shown) and faces the movable arc electrode 2. The movable arc electrode 2 is fixed to a hollow operation rod 7 which is connected to an operation mechanism portion (not shown) by an insulating rod or the like. A puffer cylinder 5 coaxial with the operation rod 7 is fixed so as to surround the operation rod 7. On the front surface of the puffer cylinder 5 and on the side of the fixed arc electrode, a nozzle 3 is fixed by a movable energizing contact 4 so as to surround the movable arc electrode 2 while holding a gas flow path. A puffer piston 6 supported by a container with an insulating material is inserted between the operation rod 7 and the puffer cylinder 5. A communication hole 8 is provided in the front surface of the shield plate of the operation rod 7 so that the hollow portion of the operation rod 7 communicates with the inside of the puffer cylinder 5. As shown in FIGS. 2 and 3, the communication hole portion of the operating rod 7 is
An axial groove 9 is provided to reduce the radius. The outer surface of the operating rod 7 is in contact with the inner surface of the puffer piston 6 and slides, and the groove 9 has a structure having a gap.

Next, the operation of this embodiment will be described. When the circuit breaker is in the closed state, the movable arc electrode 2 and the fixed arc electrode 1 are in contact with each other and are in the energized state. Once an open command is issued, the movable arc electrode 2 connected to the operation mechanism section moves, the contacts open and an arc 10 is generated. At this time, the puffer cylinder 5 also moves at the same time, and the gas is compressed by the relative movement with the puffer piston. Further, the hot gas whose temperature is increased by being exposed to the arc pushes the gas in the hollow portion of the operating rod 7 into the puffer cylinder 5 through the communication hole 8 provided in the operating rod 7, and the hot gas itself is also passed through the puffer cylinder 5. Move in and contribute to the pressure rise. When the contact opening progresses, the communication hole 8 passes through the puffer piston 6 and the hot gas is discharged into the container. At this time, the outer surface of the operating rod 7 and the inner surface of the puffer piston 6 contact and slide, but since the communication hole 8 is provided in the groove 9 having a smaller radius, it does not come into contact with the inner surface of the puffer piston 6. Absent. As a result, there is no risk of damaging the inner surface of the puffer piston 6 or generating foreign matter. Further, the gas leakage is suppressed to a minimum and the radial axial deviation at the time of contact opening is suppressed.

Another embodiment of the present invention will be described. Although the groove 9 is provided in the operating rod 7 in FIG. 1, the same effect can be obtained by providing the groove on the inner surface of the puffer piston 6 with respect to the communication hole 8. The same effect can be obtained by inserting a sliding member such as a portion other than the communication hole 8.

〔The invention's effect〕

As described above, in the present invention, the communication hole 8 is provided in front of the shield plate of the hollow operation rod 7 to which the movable arc electrode 2 is fixed, and when the contact is closed, the operation rod 7 is connected through the communication hole 8. The hollow portion is connected to the inside of the puffer cylinder 5, and the communication hole 8 has a structure that passes through the puffer piston 6 and is withdrawn into the container during opening. A groove 9 is provided, a groove is provided on the inner surface of the puffer piston 6 facing the communication hole 8, or
By inserting a sliding material between the inner surface of the puffer piston 6 and the outer surface of the operating rod 7 other than the communication hole 8,
It is possible to provide a circuit breaker with excellent insulation performance by preventing damage due to the communication hole to the inner surface of the puffer piston 6 and suppressing the generation of foreign matter, preventing gas leakage, and also shifting the radial axis when opening. It is effective in providing a circuit breaker which has an excellent breaking performance.

[Brief description of drawings]

1 is a sectional view of an arc extinguishing chamber of a puffer type gas circuit breaker showing an embodiment of the present invention, FIG. 2 is a sectional view of the puffer type gas circuit breaker shown in FIG. Figure is III-I in Figure 2.
II is a sectional perspective view, and FIGS. 4 and 5 are sectional views showing an arc extinguishing chamber of a conventional puffer type gas circuit breaker. 1 ... Fixed arc electrode, 2 ... Movable arc electrode, 3 ... Nozzle, 4 ... Movable energizing contact, 5 ... Puffer cylinder, 6 ... Puffer piston 7 ... Operation rod, 8 ... Communication hole, 9 ... Groove, 10 ... Arc, 11 ... Gas flow, 12 ... Fixed energizing contact, 13 ... Current collector, 14 ... Insulating rod, 15 ... Fixed part support.

Claims (1)

(57) [Claims] 1. A pair of movable and fixed arc electrodes are provided in a container in which an arc-extinguishing gas is sealed, and the movable arc electrodes are supported by a hollow operation rod connected to an operation mechanism section by an insulating rod or the like. A puffer cylinder coaxial with the operation rod is fixed to the operation rod so as to surround the operation rod, and a nozzle is provided on the front surface of the puffer cylinder and on the side of the fixed arc electrode so as to surround the movable arc electrode while holding the gas flow path. Is fixed by a movable energizing contactor etc., a puffer piston supported by a container with an insulator is inserted between the operation rod and the puffer cylinder, and a communication hole is provided in the front of the shield plate of the operation rod for operation. In a puffer-type gas circuit breaker that communicates the hollow part of the rod with the interior of the puffer cylinder, the communication rod of the operation rod has a groove in the axial direction to reduce the radius. Of the outer surface is a structure in which sliding contact via an inner surface and oxalic Dozai the puffer piston, puffer type gas circuit breaker groove comprising a clearance.