JPH0715814A - Gas insulated switching device - Google Patents

Abstract

PURPOSE:To suppress he temperature rise of a grounded tank without an increase in its diameter, by forming the grounded tank out of a clad plate made of a stainless steel plate with the lining of a copper plate. CONSTITUTION:A grounded tank 1 is formed out of a clad plate consisting of stainless steel plate 3 and a copper plate 4. Therefore, the usable temperature range of the material of the tank 1 can withstand a temperature rise over 30K, and the temperature rise of the tank 1 which is caused by its material becomes limitless (but, the limitation of temperature rise which is associated with its safety is left intact). Also, since the stainless steel plate 3 is used, the tank 1 has an enough mechanical strength as a tank, and when the diameter of the tank 1 is increased as the current-cavying capacity is increased, its plate thickness is kept within the manufacturable range associated with conventional manufacturing equipments. Further, since the stainless steel plate 3 and copper plate 4 both non-magnetic, no heat generation due to the iron loss caused by an AC magnetic field is present in the tank 1, and any overcurrent flows through the copper plate 4 having a small resistivity in the tank 1. Thereby, the temperature rise of the tank 1 can be suppressed without an increase in its diameter.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas-insulated switchgear (hereinafter referred to as GIS) used in a substation or switchgear.

[0002]

2. Description of the Related Art A GIS is constructed by insulating and supporting a high-voltage conductor in a grounded tank (hereinafter referred to as a tank), which is filled with an insulating gas such as SF ₆ gas. Since amperes of current flow, heat is generated due to the small resistance of the high voltage conductor. This heat is transmitted to the tank through the SF ₆ gas sealed in the tank and raises the temperature of the tank. An AC magnetic field is generated around the high-voltage conductor due to the current flowing through the high-voltage conductor.However, when the tank material is a magnetic material, this AC magnetic field causes iron loss in the tank and the loss appears as heat. Increase the temperature of the tank. Furthermore, when three high-voltage conductors are arranged in the same tank as in a three-phase device, the high-voltage conductor is not arranged in the center of the tank, so the magnetic field generated from the high-voltage conductor is Cross each other. Therefore, eddy current locally flows in the tank, heat is generated by the resistance of the tank, and the temperature of the tank rises.

Due to the various factors described above, the temperature of the GIS tank during operation rises. In order to operate the GIS safely, it is considered that such a temperature rise of the tank is within the usable temperature range of the tank material, or that there is no problem even if a person touches the tank. Temperature rise up to)) or less.
Further, the temperature rise of the tank also raises the temperature of the high-voltage conductor, which exceeds the temperature rise standard value for the current-carrying part, which also causes a reduction in the current-carrying performance of the device.

In recent years, as the demand for electric power has increased, the voltage and current carrying capacity of GIS have increased. Therefore, the current flowing through the high-voltage conductor increases, and the amount of heat generation increases.
Further, along with this, since the AC magnetic field is also increased, iron loss due to the magnetic field and heat generation due to eddy current are increased depending on the tank material and the arrangement of the high-voltage conductor, and the temperature rise of the tank is increasing. Therefore, when the current-carrying capacity is large, in order to keep the amount of temperature rise below the specified value, the tank material is appropriately selected and the tank diameter is enlarged. Hitachi Review VOL64 (issued in March 1982)
Describes a GIS in which a copper magnetic shield is locally arranged inside a mild steel tank. G like this
In IS, eddy currents flow in the magnetic shield, so
The temperature rise of the tank can be suppressed. However, since the inner surface of the tank becomes uneven by disposing the magnetic shield, the electric field in the tank is disturbed, and in particular, the tank diameter must be increased in order to attract the electric field at the end of the magnetic shield. In addition, as a tank material, a magnetic steel material (SS400 material) or stainless steel with a high resistivity (S
There is also known a GIS in which direct heat generation of a tank due to a magnetic field is reduced by using a non-magnetic material such as aluminum without using US304). However, such a conventional G
The IS has a problem that the tank diameter becomes large and the arrangement configuration of the GIS may be limited.

As such a conventional example, FIG. 5 and FIG.
Figure 3 shows a cross-sectional view of a three-phase short bus bar with a three-phase package and a short overall length. Since the three-phase short busbar has a short overall length, the volume inside the tank 1 is small, and the heat generated by the high-voltage conductor 2 is easily transmitted to the tank. Moreover, since there are three high voltage conductors 2a, 2b and 2c in the tank 1, the amount of heat generated is large. Therefore, in order to suppress the temperature rise amount of the tank 1 to be equal to or less than the specified value, it is necessary to increase the diameter of the tank 1 and increase the volume. Considering the aluminum material (A5083 material, A5052 material) that has been generally used as the material of the tank 1 in the past, the temperature increase amount of A5083 material is as low as 25K from the operating temperature range of the material. The diameter of the tank 1 must be increased in order to keep the value below the specified value. A5052 material is the temperature rise of up to 30K by the safety standards is permitted, the mechanical strength is weaker than the other materials (tensile strength -A5052 material: 24kgf / mm ^2, A5083 material: 28 kgf / mm
² ). Therefore, if the diameter of the tank is increased as a measure for temperature rise, the tank
Since the plate thickness becomes thicker, the tank cannot be manufactured by the conventional equipment for manufacturing a gas-insulated switchgear tank. Steel material (SS400 material-Tensile strength: 41 to 52 kgf / mm ² )
And stainless steel (SUS304 material-tensile strength: 53kgf /
mm ² ) has sufficient mechanical strength, but steel (SS
(400 P) and magnetic material, it generates heat due to iron loss, and stainless steel (SUS304 material) has a large resistivity of 72 μΩcm (SS400 material: 14.5 μΩcm, A5052 material: 4.9 μΩc).
m). Since three-phase devices generate heat due to eddy currents, neither can be used when the current carrying capacity is large.

Therefore, in the three-phase short bus, A5083 is used.
When a tank having a large diameter is used as the material, as shown in FIG. 7, the tank diameter of the three-phase short bus bar 5 is different from that of other equipment (three-phase bus bar 6).
And the diameter of the disconnector 7) becomes larger than the tank diameter, so that the legs 8 of other devices must be enlarged correspondingly and the height must be aligned with the three-phase short bus bar 5. In other words, there is a problem that the height of the entire gas-insulated switchgear becomes high even if only the tank diameter of the three-phase short bus bar is large.

[0007]

SUMMARY OF THE INVENTION The present invention has been proposed to solve the problems of the prior art as described above, and its object is to have a usable temperature range that can withstand a temperature rise up to 30K. The object of the present invention is to provide a gas-insulated switchgear that has sufficient mechanical strength as a tank, and is made of an ideal material that is a non-magnetic material and has a low resistivity as a tank material.

[0008]

In order to achieve the above object, according to the present invention, a high voltage conductor is fixed in a grounded tank through an insulating support member, and the insulating support member and the tank are sealed. A gas-insulated switchgear for insulating a high-voltage conductor with SF ₆ gas, wherein the tank is composed of a clad plate composed of a stainless steel plate and a copper plate.

[0009]

In the GIS of the present invention having the above-described structure, the tank is composed of the clad plate composed of the stainless steel plate and the copper plate so that the usable temperature range of the material can withstand the temperature increase of 30 K or more. The temperature rise limitation due to the tank material is eliminated (however, the temperature rise limitation of 30K remains for safety reasons). Further, since stainless steel is used, it has sufficient mechanical strength as a tank, and even if the diameter of the tank is increased with the increase of the current carrying capacity, the plate thickness of the tank can be kept within the range that can be manufactured by conventional equipment. Furthermore, since stainless steel and copper are non-magnetic materials, there is no heat generation due to iron loss due to an alternating magnetic field. Also, the resistivity of stainless steel is
While the resistivity of copper is 72 μΩcm, the resistivity of copper is about 1.78 μΩcm, so most of the eddy current generated by the magnetic field that crosses the clad plate flows through the copper material with low resistivity, so it is caused by the eddy current. Heat generation is also smaller than in the past.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the gas-insulated switchgear according to the present invention will be specifically described below with reference to FIGS. The same parts as those in the conventional technique shown in FIGS. 5 to 7 are designated by the same reference numerals.

The basic structure of this embodiment is shown in FIGS.
This is similar to the prior art shown in FIG. As shown in FIGS. 1 and 2, high voltage conductors 2 a to 2 c are arranged in the tank 1.

In addition to the basic component structure as described above, in this embodiment, the tank 1 is made of stainless steel 3 and copper 4.
It is made of a clad plate, and the inside is made of copper 4. Stainless steel 3 for ensuring mechanical strength is 30
Since the use as a pressure vessel material is allowed even if the temperature rises above K, the temperature rise limitation by the tank material such as A5083 material is eliminated (however, the temperature rise limitation remains from the viewpoint of maintenance safety as a product). Further, since stainless steel is used, the mechanical strength is strong, and it is not necessary to increase the tank diameter in order to suppress the temperature rise due to heat generation from the high-voltage conductor to a specified value or less. Furthermore, since stainless steel and copper are non-magnetic materials, there is no heat generation due to iron loss caused by an alternating magnetic field. Further, although the electrical resistivity of stainless steel is high, the electrical resistivity of copper is sufficiently low that most of the eddy current due to the magnetic field flows toward the copper, so that heat generation due to this is small and it is not a problem. Further, it is not necessary to dispose a magnetic shield, and since there is no unevenness in the tank 1, the electric field is not disturbed and the electric field design is easy.

Therefore, even if the volume of the tank is small like a three-phase short bus bar, the temperature rise of the tank can be suppressed to a specified value or less, and the equipment having a large gas volume adjacent thereto is not subject to the temperature rise restriction. It is possible to construct a gas insulated switchgear with a tank diameter equivalent to that of the equipment. Therefore, as shown in FIG. 4, since the tank diameters of the respective devices of the gas-insulated switchgear are the same, the height of the legs does not increase as in the conventional example, and the height of the gas-insulated switchgear is kept low. To be

[0014]

As described above, in the present invention, the tank diameter is inevitably increased due to the problem of temperature increase by forming the tank with the clad plate made of the stainless steel plate and the copper plate. A highly reliable gas-insulated switchgear that has the same tank diameter as other equipment.

[Brief description of drawings]

1 is a partial cross-sectional view of a tank according to the present invention.

FIG. 2 is a block diagram showing a gas insulated switchgear according to a typical embodiment of the present invention.

FIG. 3 is a sectional view of a three-phase short bus bar according to the present invention (A- in FIG. 1).
(A line sectional view)

FIG. 4 is a cross-sectional view of a three-phase short bus bar according to the present invention.

FIG. 5 is a sectional view of a conventional three-phase short bus bar.

FIG. 6 is a cross-sectional view of a conventional three-phase short bus bar.

FIG. 7 is a block diagram showing a conventional gas-insulated switchgear.

[Explanation of symbols]

1 ... Tank, 2a, 2b, 2c ... High-voltage conductor, 3 ... Stainless steel, 4 ... Copper, 5 ... Three-phase short busbar, 6 ... Three-phase busbar, 7
… Disconnectors, 8… legs.

Claims (1)

[Claims] 1. A gas-insulated switchgear in which three-phase high-voltage conductors are housed together in a grounding tank filled with insulating gas, wherein the grounding tank is composed of a clad plate in which a copper plate is joined inside a stainless steel plate. Gas insulated switchgear characterized by