JPH03222222A - Puffer type gas breaker - Google Patents

Abstract

PURPOSE:To minimize the lowering of dielectric strength and breaking performance at the time of exposure to an arc by making boron nitride powders, contained in a nozzle composed of ethylene tetrafluoride, have the components of grades having different mean particle diameters, and making one of the components have below 2mum mean diameters and one of the remaining components 2mu or more diameters. CONSTITUTION:The nozzle of a gas breaker is composed of ethylene tetrafluoride 1 including boron nitride powders 2 and 3, and the boron nitride powders 2 and 3 are composed of components of at least two kinds or grades having different mean particle diameters. That is, the boron nitride powders 2 and 3 are composed so that the mean particle diameter of at least one grade component 3 is below 2mum, and that of at least one grade component 2 of the remaining components is 2mum or more. Consequently the minimization of arc energy 6 to be absorbed in the nozzle and also the quick dispersion of the little arc energy 6 absorbed is made possible. This permits the minimization of the lowering of dielectric strength and breaking performance at the time or exposure to an arc.

Description

[Detailed Description of the Invention] [Object of the Invention (Industrial Application Field) The present invention relates to a puffer type gas circuit breaker,
In particular, the present invention relates to a puffer-type gas circuit breaker that makes it possible to improve the arc resistance of a nozzle that sprays arc-extinguishing gas onto the arc when the circuit is shut off.

(Prior Art) When a current is interrupted in a cass breaker, an arc is generated between the fixed and movable electrodes.

In order to extinguish this arc, a puffer type gas circuit breaker has conventionally been used in which a flow of insulating gas such as SF6 gas is sprayed onto the arc from an insulating nozzle made of fluororesin. This puffer type gas circuit breaker has a fixed contact and a movable contact that can be connected and separated in a container filled with arc-extinguishing gas,
By compressing the puffer chamber consisting of a puffer piston and a puffer cylinder installed in the movable contact section, arc-extinguishing gas is compressed and guided to the nozzle section, where it is sprayed onto the arc generated between the fixed and movable contact sections. This is to extinguish the arc.

By the way, in such a puffer type gas circuit breaker,
When an insulator made of fluororesin is exposed to an arc, the energy radiated from the arc penetrates into the interior of the fluororesin and is absorbed, causing voids or carbonization inside the nozzle, significantly reducing insulation performance. At the same time, there was a possibility that the nozzle feed would be worn out, and the gas flow state would be different from the initial state, causing a decrease in the shutoff performance.

In order to prevent this, in the invention described in Special Vehicle Publication No. 1-45690, at least the surface layer of the part of the nozzle exposed to the arc is coated with fluorine containing highly thermally conductive inorganic powder and pigment particles having an average particle size of 1 μm or less. Composed of resin,
Arc energy absorbed by the pigment particles is quickly diffused by the highly thermally conductive inorganic powder, and cracks are prevented by filling the gaps between the fluororesin and inorganic powder particles with small-sized pigment particles.

In addition, in the invention described in Special Vehicle No. 1 37822,
Considering that arc energy entering and being absorbed inside the nozzle is essentially the cause of deteriorating the insulation, the nozzle is made of a fluororesin containing boron nitride powder to increase the light reflectance of the composition by 60% or more. This prevents arc energy from being absorbed by the nozzle.

(Problems to be Solved by the Invention) However, as in the invention of Special Vehicle No. 1-45690 mentioned above, the method of absorbing ac energy by filling pigment particles is not suitable for large-capacity gas circuit breakers that have been developed in recent years. If the arc energy increases more than the current level in the future due to oxidation, no matter how quickly it spreads, it may cause the insulation to deteriorate, as stated in Special Vehicle Publication No. 1-37822. Inevitable.

In addition, in the invention of Special Vehicle No. 1-37822, even if the nozzle is made of a fluororesin containing boron nitride powder and the light reflectance of the composition is 60% or more, the light reflectance is completely 100%. It is impossible to do so, and if the arc energy increases in the future due to the increase in the capacity of gas circuit breakers, which has been progressing in recent years, the absorbed arc energy will cause cracks in the gaps between the fluororesin and boron nitride powder particles. You can't avoid what might happen.

In this way, the conventional techniques are required to achieve mutually contradictory effects, and cannot completely satisfy these effects.

Because of these mutually contradictory effects, when gas circuit breakers have a larger capacity in the future, there remains the possibility that the nozzle will be exposed to arc, resulting in a decrease in dielectric strength and a decrease in interrupting performance. .

The present invention was proposed in view of the following two problems, and its purpose is to provide a puffer with a nozzle that can minimize the deterioration of dielectric strength and breaking performance when exposed to arc. Our objective is to provide a type of gas circuit breaker.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above object, in the puffer type gas circuit breaker of the present invention, the nozzle is made of tetrafluoroethylene containing boron nitride powder. The boron nitride powder contains at least two classes of components with different average particle sizes, at least one of which has an average particle size of less than 211 m, and at least one of the remaining components The average particle size of the particles was 2 μm or more.

(Function) With the above configuration, in the puffer type gas circuit breaker of the present invention,
Since boron nitride, which is a white particle, has an extremely high light reflectance, most of the arc energy irradiated to the nozzle is reflected. Also, a small amount of arc energy that is not reflected by boron nitride enters the nozzle, but because boron nitride has a very high thermal conductivity, it is quickly diffused.

Furthermore, the average particle size of tetrafluoroethylene is generally between 10 and 100
μm, so by creating a structure in which the gaps between the particles are filled with boron nitride having two types of average particle diameters, large and small,
It becomes possible to efficiently fill the gaps between the particles of ethylene tetrafluoride with boron nitride, and the above-mentioned arc energy reflection efficiency and absorption efficiency of boron nitride can be ensured.

(Implementation) An embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

The nozzle of the gas circuit breaker according to this embodiment uses a material in which tetrafluoroethylene is filled with boron nitride. That is, FIG. 1 is an enlarged sectional view showing the outline of the particle structure inside the nozzle of the puffer type gas circuit breaker of this example. In this example, the diameter of the tetrafluoroethylene particles 1 is - 10~
Since the particle size is 100 μm, the gap between the tetrafluoroethylene particles is divided into boron nitride particles 2 with an average particle size of 0.5 μm and boron nitride particles with an average particle size 3 of 0.5 μm.
It has a structure filled with boron nitride particles 3 of Ilm.

The particle size distribution of boron nitride in this nozzle is shown in FIG.

As shown in FIG. 2, in this example, the particle size distribution of boron nitride is about 0.5 .mu.m and has a maximum at about 3 .mu.m. This means that the mode of the particle size distribution of filled boron nitride is approximately 0. 5μm component and average particle size of about 3μ
This means that it consists of two components, component m, and the average value of the particle size of each component is also approximately equal to these values.

Next, the effects of this embodiment will be explained using FIG. When the nozzle of this example is irradiated with arc energy 4,
Since boron nitride particles are white, their light reflectance is extremely high. As a result, most of the arc energy incident on the nozzle is reflected, becomes reflected light 5, and does not enter the inside of the nozzle. Although a small amount of arc energy 6 enters the inside of the nozzle, the thermal conductivity of boron nitride is 0. 14 [c a
1/cm・sec・deg], so it is quickly diffused and the heat is not concentrated locally.

Due to the above-mentioned effects, the puffer type gas circuit breaker in this embodiment can minimize the arc energy absorbed by the nozzle, and can quickly diffuse the small amount of arc energy absorbed. This makes it possible to minimize the decline in dielectric strength and interrupting performance when exposed to arc.

In particular, in this example, boron nitride having two types of smaller average particle sizes was embedded between tetrafluoroethylene having an average particle size of 10 to 1007 zm. The gaps between the particles of ethylene chloride can be reliably filled with boron nitride, and as a result, the arc energy reflecting and absorbing effects of boron nitride are reliably exhibited.

(Other Examples) In the above examples, the average particle diameters of the boron nitride powder filled in tetrafluoroethylene were approximately 0.5 μm and approximately 3 μm, but one of the average particle diameters was less than 211 m and the other was When the particle size is set to 2 μm or more, sufficient practical effects can be achieved.

In addition, the boron nitride powder packed into tetrafluoroethylene is
It was composed of components from two particle size classes,
Furthermore, the third. It goes without saying that the same effect can be obtained even if the fourth component is contained.

[Effects of the Invention] As explained above, in the puffer type gas circuit breaker according to the present invention, the nozzle is made of ethylene tetrafluoride containing boron nitride powder, and the boron nitride powder contained is at least two types having different average particle sizes. of the components, at least one of which has an average particle diameter of less than 2 ltm, and at least one of the remaining components has an average particle diameter of 2 μm or more. Therefore, it is possible to minimize the arc energy absorbed by the nozzle, and it is also possible to quickly diffuse the small amount of arc energy absorbed, improving dielectric strength and breaking performance when exposed to arc. It has now become possible to provide a puffer-type gas circuit breaker equipped with a nozzle that can minimize the decrease in

[Brief explanation of drawings]

FIG. 1 is an enlarged sectional view showing the particle structure inside the nozzle and the traveling path of incident arc energy in an embodiment of the gas circuit breaker of the present invention, and FIG. 2 is an enlarged sectional view of the gas circuit breaker in the embodiment of FIG. 1. It is a particle size distribution diagram of boron nitride powder contained in a nozzle. 1... Ethylene tetrafluoride 1'l element, 2... Boron nitride R element, 3... Boron nitride particles, 4... Quenel key to the nozzle surface, 5... Reflected arc Energy, 6... Arc energy penetrated inside the nozzle Toshiba Corporation

Claims (1)

[Claims] (1) A container filled with arc-extinguishing gas has a fixed contact and a movable contact that can be moved in and out, and compresses a puffer chamber consisting of a puffer piston and a puffer cylinder provided in the movable contact. In a puffer-type gas circuit breaker having an arc-extinguishing chamber that compresses arc-extinguishing gas and guides it to a nozzle part to blow and extinguish an arc generated between a fixed and movable contact, the nozzle is made of boron nitride powder. The boron nitride powder is composed of at least two grades of components having different average particle sizes, and the average particle size of at least one of the grade components is less than 2 μm. A puffer-type gas circuit breaker characterized in that the average particle diameter of at least one class component among the remaining components is 2 μm or more.