JPS6014455B2 - gas butsing - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a gas bushing provided in electrical equipment.

Conventionally, oil has been used as an insulating medium for pushers, and oil-immersed paper capacitor bushingsogs have been widely used, which improve potential distribution by using capacitors with electrodes made of paper and a thin metal box.

However, such bushings have the disadvantage that there is a risk of fire in the unlikely event of an accident. On the other hand, as SF6 gas has come to be used in switchgear equipment due to its excellent insulation performance and arc extinguishing performance, and as the use of gas insulated switchgear has expanded, the bushings have been using SF6 gas as an insulating medium.
Gas bushing using gas appeared.

SF6 gas, like other gases, improves its insulation performance by pressurizing it, so gas insulated switchgear generally requires 3.
SF6 gas pressurized to ~5 atmospheres is used, and conventional gas bushings are also at the same pressure. Therefore,
If an insulator tube, which is commonly used as a container to seal gas in a gas bushing, breaks, the pieces will be explosively scattered tens of meters due to the energy of the pressurized gas, causing harm to other equipment and people. It has the disadvantage that it may cause damage. In view of these points, the present invention provides a gas bushing that has no fear of fire or explosion when the insulator pipe breaks.

FIG. 1 shows an embodiment of the present invention.

Figure 1 is a cross-sectional view showing the structure of a gas bushing.
2 is a flange fixed to a gas insulated device 3, and 4 is an insulator tube, which is attached to the flange 2 provided with an earth potential crab pole 5.

6, 7, and 8 are intermediate electrodes arranged in the same D shape as the conductor 1 between the conductor 1 and the earth potential electrode 4; 9 to 14 are disk-shaped solid insulators; I support 8.

A space 15 formed by the conductor 1, the intermediate electrode 6, and the solid insulators 9, 10, a space 16 formed by the intermediate electrodes 6, 7, the solid insulators 11, 12, and the intermediate electrodes 7, 8 and the solid insulator 12. As shown in FIG. In this configuration, the space 20 is filled with SF6 gas close to atmospheric pressure.The flange 2 attaches the pushing to the gas insulated device 3, and the inside 18 is filled with SF6 gas at the specified pressure for the gas insulated device. It is enclosed.

In this case, the strength of the internal electric field is adjusted by adjusting the capacitance or opposing area between each electrode, as shown in Figure 3 ■ (the conventional one is shown in Figure 3 ■), and the surface of the electrode 8 is adjusted. The electric field strength is lowered to a value that can be sufficiently withstood by SF6 gas at atmospheric pressure, and the highest part of the electric field is made so that it can be withstood by the gas pressure of gas-insulated equipment, and the middle part is also set to a pressure corresponding to each electric field.
For example, 15 parts is 4 atm, same as the equipment, 16 parts is 3 atm, 17
It is preferable that the pressure be 2 atm for 1 part and 1 atm for 20 parts. By doing so, the pressure difference between the spaces is reduced, the strength against gas pressure is reduced, the risk of gas leakage is reduced, and the device is also small and has good withstand voltage performance. In FIG. 3, r is the radius of the conductor, r5 is the radius of the ground electrode, and r6 to r8 are the radii of the intermediate electrodes. As can be seen in this example, S
Since the F6 gas pressure is atmospheric pressure, no explosion occurs when the insulator tube breaks.

It is also possible to slightly pressurize part 1 by 0.3 atm. In this case, the amount of gas corresponding to the parts 15, 16, and 17 surrounded by the intermediate electrodes will be reduced compared to the case without these parts. Therefore, the total amount of energy held by the pressurized gas during an explosion is reduced, and the amount of scattering is also reduced. According to the present invention, as described above, even if the insulator pipe breaks, there will be no explosive scattering, and there is no risk of fire unlike oil-filled bushings.
A bushing that is favorable for safety can be obtained in a smaller size, and its effects are significant.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view of one embodiment of the present invention, Fig. 2 is an explanatory diagram showing the conductor placed in the same D shape, each electrode, and the electric field strength between them, and Fig. 3 is an insulator that supports the intermediate electrode. This shows a structure that maintains airtightness. In the figure, 1 is a conductor, 4 is an insulator tube, 5 is an earth potential electrode, 6, 7
, 8 are intermediate electrodes, and 9 to 14 are insulators. In addition,
The same reference numerals in each figure indicate the same or corresponding parts. Figure 2 Figure 3 Figure 1

Claims (1)

[Claims] 1. In a conductor surrounded by an insulating tube or a solid insulating tube filled with insulating gas as an insulating medium, first and second tubes are placed concentrically from the conductor side between the conductor and the earth potential electrode. intermediate electrodes are sequentially arranged and held airtight with a solid insulator, a first space is created between the conductor and the first intermediate electrode, and a second space is created between the first and second intermediate electrodes. A third space is formed between the second intermediate electrode and the insulating tube or the solid insulating cylinder, and the pressure in each space is gradually lowered from the first space to the third space. A gas bushing characterized by being filled with an insulating medium.