JPS61227329A - Gas insulated electric appaliance - 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 [Technical Field of the Invention] The present invention relates to improvements in gas-insulated electrical equipment.

[Technical background of the invention and its problems]

In recent years, the size of gas-insulated electrical equipment has been significantly reduced compared to conventional air-insulated electrical equipment due to the use of SF6 gas, which has excellent insulating properties. On the other hand, reducing the distance between the electrical circuit conductor to which high voltage is applied and the grounded metal case and reducing the device dimensions has created a new problem in that the temperature of the device tends to rise due to the heat generated by the current flowing through the electrical circuit conductor. caused a problem. In particular, the contact portions of electrical circuit conductors often exhibit the highest temperature of the device because of their high contact resistance. In order to deal with these problems, a method has been considered in which a hole is made in the metal shield provided at the 9th point to alleviate the electric field at the contact point, thereby improving heat dissipation through convection.

FIG. 3 is a cross-sectional view showing the structure of a contact portion of a conventional gas-insulated electric device made by this method. A grounded metal case 1 is filled with an insulating gas 2 and houses a circuit conductor 3 through which a main circuit current flows. This electrical circuit conductor 3
is divided into conductive parts 31 and 3b, both of which can be electrically connected to and separated from each other by contact parts JeK.

Further, this contact portion 3c is surrounded by a metal shield 4 to prevent concentration of one electric field when a high voltage is applied.

In such a configuration, the heat generated from the contact portion 3c may flow inside the metal shield 4, causing the contact portion 3c to overheat. For this reason, even if holes are made in the metal shield 4 to improve heat dissipation through convection, there is a limit to its effectiveness.On the other hand, electrically, the electric field concentrates in the holes, reducing dielectric strength. There was a drawback to that.

1+. As a method different from the conventional method described above, a method of increasing the emissivity by coloring the entire surface of the electric circuit conductor and the entire inner surface of the metal case is known from Japanese Patent Laid-Open No. 5G-190215. , this method requires time and cost to manufacture.

It wasn't practical.

[Purpose of the invention]

The present invention has been made to solve these drawbacks, and provides gas-insulated electrical equipment that can quickly radiate heat from the contact portions of electrical circuit conductors to the outside of the equipment and that does not cause a decrease in dielectric strength. The purpose is to provide

[Summary of the Invention] [In order to achieve the above object, the present invention provides a gas-insulated electric device in which a circuit conductor to which a high voltage is applied is housed in a grounded metal case filled with an insulating gas. The present invention is characterized in that at least one of the inner and outer surfaces of the metal shield surrounding the contact portion of the electric circuit conductor is anodized and colored black.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to the drawings. First, one embodiment will be described with reference to FIG. 1. Here, the same parts as those in FIG. 3 are given the same reference numerals, the explanation thereof will be omitted, and only the different points will be explained. That is, the inner and outer surfaces of the metal shield 4, the inner circumferential surface of the grounded metal case 1 facing the metal shield 4, and a part of the surface of the contact portion 3c are each anodized to have a black color 5.
is colored.

Hereinafter, the operation of the gas insulated electrical equipment configured as described above will be explained. Generally, when there is a heating element on the inside and a heat receiving element surrounds it from the outside, the amount of heat radiated (and thus transferred) from the heating element to the heat receiving element can be expressed by equation (1).

Here, Q: Amount of heat transferred from the heating element to the heat receiving element by radiation σ: I Ruthmann's constant T1: Temperature of the heat receiving element T2: Temperature of the heating element A1: Inner surface area of the heat receiving element A2: Surface area of the heating element ε1 : Emissivity of heat receiving body: 62 Emissivity of heat generating body: The larger the amount of heat Q transferred from the heat generating body to the heat receiving body, the better the heat radiation to the outside, and the temperature of the heat generating body itself can be suppressed. (1) Equation: emissivity g1 of the heat receiving element and heating element
The larger m 12 is, and the larger the areas A1 and A2 of the heat receiving element and the heating element are, the greater the amount of heat transferred from the heating element to the heat receiving element.

Therefore, as shown in FIG. 1, by coloring the surface of the contact portion 3c, which is a heating element, black, and by coloring the inner surface of the metal shield 4, which is a heat receiving element, black by alumite treatment, the emissivity of both can be increased. However, heat is quickly transferred from the breaking point portion 3c to the metal shield 4. On the other hand, if the surface of the metal shield 4 and the inner surface of the metal case 1, which is a heat receiving body, are blackened by alumite treatment, the emissivity of both will increase, and the transfer of heat from the metal shield 4 to the metal case 1 will be reduced. , become prompt.

As a result, overall, the heat generated at the contact portion 3C is quickly transferred to the metal case 1 via the metal shield 4.

Therefore, the heat generated at the contact portion 3C is quickly released to the outside of the device, and the heat generated at the contact portion 3C is quickly released from the inside of the device, especially the contact portion 3C.
can prevent overheating. Nine, metal shield 4
0 surface is anodized and blackened, so
Since an oxide film with excellent insulation is formed on the surface, the insulation performance of the metal shield 4 is improved. Furthermore, since the inner surface of the metal case 1 is also anodized and blackened, it is possible to suppress the electric field generated by the foreign metal when it is present in the electric field area on the opposite case side of the high electric field concentration area, and to insulate the metal case 1. Contributes to improved pressure resistance.

From the above, the present invention can be applied to a metal shield 4 with a hole 4a as shown in FIG. 2, without degrading the insulation performance even if the electric field is concentrated.

The heat generated at the contact portion 3C can be released to the outside of the device by two means: convection and radiation. If the electrical circuit conductor 3 is a switching contact for a gas-insulated switch, the property of hardening the surface of the metal shield 4 by alumite treatment can be used to prevent arcing that occurs when the switch is opened or closed. A new advantage is also created that it can be used as a metal shield with sufficient strength. -The black 50 coloring is applied to the contact area Jc, metal shield 4,
It is not necessary to color the entire metal case 1, and the same effect can be obtained even if only the surface of the contact portion 30 is colored. Similar effects can be obtained by partially coloring only the inner surface of the metal shield 4, only the outer surface, only the inner surface of the metal case 1, or only a combination thereof.

〔Effect of the invention〕

According to the above-mentioned invention, since the surface of the metal shield is anodized and colored black, the heat generated at the contact part of the electric circuit conductor can be quickly radiated to the outside of the device, and the dielectric strength voltage is reduced. We can provide gas insulated electrical equipment that never fails.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing the structure of a contact portion of one embodiment of a gas-insulated electrical device according to the present invention, and FIG. 2 is a cross-sectional view showing the structure of a contact portion of another embodiment of a gas-insulated electrical device according to the present invention. ,
FIG. 3 is a sectional view showing the structure of a contact portion of an example of a conventional gas-insulated electric device. 1... Grounded metal case, 2... Insulating gas, 3
...Circuit conductor, 3a...Conductive part, 3b...Conductor part, 3c...Contact part, 4...Metal shield, 4a...
- Hole drilled in metal shield 2d, 5...Black colored part Applicant's representative Patent attorney Suzue Takehiko-ゝ-2

Claims (4)

[Claims] (1) In gas-insulated electrical equipment in which a conductor to which high voltage is applied is housed in a grounded metal case filled with insulating gas, a metal shield surrounding the contact portion of the conductor is used. 1. A gas-insulated electrical device characterized in that at least one of the inner and outer surfaces is anodized and colored black. (2) The gas-insulated electric device according to claim 1, wherein the inner surface of the grounded metal case facing the metal shield is partially anodized and colored black. (3) The gas-insulated electric device according to claim 1, wherein the contact portion of the electric circuit conductor is blackened by alumite treatment. (4) Claim 1 characterized in that the insulation distance between the metal shield and the metal case is the shortest and only the part where the electric field is concentrated is anodized and colored black.
Gas insulated electrical equipment as described in Section 1.