JPS6235327B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the reduction of current induced in the ground conductor of gas insulated electrical equipment.

A conventional grounding system for gas-insulated electrical equipment is shown in FIG.

In Fig. 1, reference numeral 1 denotes a bus bar, and 2a and 2b denote a bus bar 1 and a tank housed inside the bus bar 1 and filled with an insulating gas such as SF ₆ gas.
a and tank 2b are electrically insulated. 3
4 is a main ground wire that is part of a grounding network buried underground; 5 and 6 connect the main ground wire 4 to a fixture 7 provided on the mount 3, respectively. It is a ground wire. Note that 8 indicates the ground.

In such a configuration, the bus current causes the tank 2a - pedestal 3 - fixture 7 - grounding wire 6 - main grounding wire 4
An induced current flows through the circuit of - grounding wire 5 - fixture 5 - pedestal 3. This is because the magnetic flux generated by the current flowing through the bus bar 1 passes through the circuit, generating a large induced voltage and causing an induced current to flow. This causes the ground wire to overheat, which is dangerous at exposed parts, and may cause the ground wire to melt. These induced currents flow into the tank, resulting in an increase in the temperature of the tank and the bus bar.

The present invention aims to reduce the penetration amount of magnetic flux generated by a current flowing through a current-carrying conductor, thereby eliminating the above-mentioned drawbacks of the conventional devices.

Hereinafter, one embodiment of the present invention will be described based on the drawings.

FIG. 2 shows an embodiment of the present invention. In the figure, the first
The same reference numerals as those in the figures indicate the same parts, but in the present invention, the main grounding wire, which is part of the grounding network, runs from the fixture 7, which is the grounding point of one pedestal, to the fixture 7, which is the other grounding point. A grounding wire 9 is drawn up to 4, and a grounding wire 10 is similarly drawn and arranged from the other gantry grounding point. By doing this, tank 2
a. The voltages induced in the grounding wires 9, 10 and the main grounding wire 4 are induced in the same direction along the tank axis. Therefore, in the circuit configured in this way through which an induced current flows, the induced voltage of the grounding wires 9 and 10 is
The direction of the voltage induced in the main ground line 4 is opposite, and the induced voltage is reduced compared to the conventional circuit. Furthermore, since the length of the circuit becomes longer, the impedance becomes higher and the induced current can be reduced.

FIG. 3 shows another embodiment of the invention. This embodiment shows a case where the tank 2a is grounded at three points, and the grounding wire 11 is connected to the grounding point near the center of the tank.
is drawn directly below and connected to the main grounding wire 4. Note that the grounding points at both ends are grounded in the same manner as in FIG. By doing this, the induced current flowing in the grounding wire 11 is the same as the current induced in the circuit of tank 2a-grounding wire 11-main grounding wire 4-grounding wire 9.
This is expressed as the sum of currents induced in similar circuits including 0, but these currents are in opposite directions at the ground wire 11, and only a small amount of induced current flows through the ground wire 11.

Therefore, many grounding points can be provided without increasing the induced current.

FIG. 4 shows another embodiment of the present invention. This figure shows a part of the gas insulated switchgear, with the disconnector tank 12, the grounding wire 22, and the bushing tank 13.
a grounding wire 21, a grounding wire 20 to the disconnector tank 14,
Ground wires 23 and 24 are connected to the circuit breaker tank 16, a ground wire 26 is connected to the disconnect switch tank 18, and a ground wire 25 is connected to the bushing tank 19 through a frame, and each ground wire is connected to the main ground wire 4. Current transformer tank 1
5 and 17 are mechanically connected to the disconnector tanks 14 and 18, but are electrically insulated.
Note that each tank is made of metal, and contains a current-carrying conductor and is filled with insulating gas.

In such a configuration, the circuit breaker tank 16 crosses two points of grounding, the two-point grounding points of the disconnector 18 and the bushing tank 19 also cross each other, the disconnectors 12 and 14, and the bushing tank 13 Regarding the three grounding points, the center grounding wire 21 is brought down directly below, the others are crossed, and connected to the main grounding wire 4. As shown in the figure, the grounding wire from the grounding point of the pedestal at one end to the vicinity of the grounding point of the other pedestal is provided in parallel with the tank and near the pedestal. By doing so, it is possible to reduce the induced current in each ground wire as described above.

Note that the present invention can be applied not only to the embodiments but also to gas-insulated busbars.

As explained above, according to the present invention, the current induced in the ground wire can be reduced, the overheating of the ground wire can be prevented, the safety of exposed ground wires can be improved, and the melting of the ground wire due to overheating can be prevented. Further, a ground line current flows through the tank, and by reducing this current, loss in the tank can be reduced, and temperature rise in current-carrying conductors such as the tank and bus bar can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a conventional gas insulated electrical device, and FIGS. 2 to 4 are perspective views showing each embodiment of the present invention. Note that the same reference numerals in the figures indicate the same or corresponding parts. In the figure, 1...Bus bar, 2a, 2b...tank, 3...frame, 4...main ground wire, 5-6...ground wire, 7...attachment, 8...ground, 9-11...ground wire, 12...disconnector Tank, 13... Bushing tank, 14... Disconnector tank, 15... Current transformer tank, 16... Circuit breaker tank, 17... Current transformer tank, 18... Disconnector tank,
19...butching tank, 20-26...ground wire.

Claims (1)

[Claims] 1. In gas-insulated electrical equipment in which the frame of one or more electrically connected tanks containing current-carrying conductors and insulating gas is connected to a grounding network at two or more places by grounding wires, one A first grounding wire that connects the gantry grounding point and a grounding network located near the other gantry grounding point, and a second grounding wire that connects the other gantry grounding point and a grounding network located near the one gantry grounding point. A gas insulated electrical device comprising a grounding wire, the first and second grounding wires being arranged in parallel with the tank.