JPS6259524B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The object of the present invention is to reduce the current induced in the grounding wire in gas-insulated electrical equipment such as gas-insulated busbars, and to prevent problems caused by temperature rises in the grounding wire. be. For convenience, typical gas-insulated busbars will be described below.

A conventional gas insulated bus bar was constructed as shown in FIGS. 1 and 2. FIG. 1 is a plan view of the gas insulated bus bar, and FIG. 2 is a front view of the gas insulated bus bar.
In these figures, reference numeral 4 denotes a metal tank filled with insulating gas, and a main conductor 5 for energization is housed in this tank. 6 is a frame for supporting the tank 4. The grounding wires 1 and 2 are connected to a pedestal 6 or a tank 4 and are buried underground. The tanks of each phase are short-circuited by a short-circuit bar 3 to allow a sheath current to flow. The grounding wires 1 and 2 are grounded at multiple points for protection against surges, and are installed underground in the form of a net. In particular, the grounding wire 1 is configured to connect the frames of each phase on the outside of the shorting bar 3. Note that 7 is bushing and 8 is ground.

In such a configuration, when a current flows through the main conductor 5, a sheath current 11 flows through the tank 4 and shorting bar 3 of each phase. At this time, since the current flowing in the main conductor is not completely suppressed by the sheath current, induced currents 9 and 10 also flow in the ground wire.
Of these, the induced current 10 becomes particularly large because the magnetic flux leaking to the outside of the shorting bar 3 is not suppressed. Conventionally, this induced current poses a risk of causing problems such as burnout and melting of the grounding wire. It was hot.

The present invention was made in order to eliminate the above-mentioned drawbacks. This eliminates the induced current in the grounding wire that connects the phases by preventing a closed circuit from passing through the grounding wire.
The purpose is to protect the grounding wire.

Hereinafter, one embodiment of the present invention is shown in FIG. 3 (plan view) and FIG. 4 (front view).
This will be explained in comparison with FIG.

3 and 4 show an embodiment of the present invention, the basic structure of which is the same as the conventional type described above. The difference from the conventional model is that the grounding wire 1 is eliminated, and the phases are not connected by a grounding wire at the end of the tank, but are connected by the grounding wire 2 at the center of the tank, eliminating the circuit through which the induced current 10 flows. . At this time, if the grounding resistance becomes large, grounding work may be performed at an appropriate position of the grounding network to reduce the grounding resistance. In FIG. 3, induced current 9 flows, but this is not significantly affected by the presence or absence of induced current 10. In addition, the grounding wire 2 that connects the phases at the center of the tank has
Due to symmetry, almost no induced current flows.

If there is no shorting bar, the embodiment described above is also possible, but other embodiments are shown in FIG. 5 (top view) and FIG. 6 (front view). In FIG. 5, the grounding wire 1 connecting the phases is installed only at one end of the tank, and the grounding network is comb-shaped, so that a closed circuit cannot be formed through the grounding wire 1, as described above.

This effect is the same in other embodiments shown in FIG. 7 (plan view) and FIG. 8 (front view). In FIG. 7, the grounding network is S-shaped, and a circuit cannot be formed through the grounding wire 1.

Note that the present invention can be similarly applied to gas-insulated switchgear.

As described above, according to the present invention, it is possible to reduce the current induced in the grounding wire and prevent troubles due to temperature rise in the grounding wire.

[Brief explanation of the drawing]

1 and 2 are a plan view and a front view showing the structure of a conventional gas insulated bus bar, FIGS. 3 and 4 are a plan view and a front view showing an embodiment of the present invention, and FIG. 6th
The figures are a plan view, a front view, and a front view showing other embodiments of the present invention.
FIGS. 7 and 8 are a plan view and a front view showing still another embodiment of the present invention. Note that the same reference numerals in the figures indicate the same or corresponding parts. In the figure, 1...Grounding wire, 2...Grounding wire, 3...Short bar, 4...Tank, 5...Main conductor (current-carrying conductor), 6...Mountain frame, 7...Butching, 8...Ground , 9... Induced current, 10... Induced current, 11...
...sheath current.

Claims (1)

[Claims] 1. In gas-insulated electrical equipment in which a plurality of phases are provided in which a current-carrying conductor is housed in a metal tank filled with an insulating gas, and a grounding wire is provided in each phase metal tank, the metal tank of each phase is The installed ground wire is on one side of the metal tank,
A gas-insulated electrical device characterized in that the grounding wire connecting the phases is omitted at least in part, and the grounding wire does not form a closed circuit between the phases.