JPH0159803B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to gas insulated electrical equipment and, more particularly, to the construction of its ground conductor.

An example of a conventional gas insulated electric device is shown in FIG. 1 of the accompanying drawings, where 1 is a disconnector tank, 2 is a bushing tank, 3 is a disconnector tank,
4 is a current transformer tank, 5 is a circuit breaker tank, and the disconnector tank 1, bushing tank 2, and disconnector tank 3 are electrically connected to each other by ground wires 6 and 7, and to the circuit breaker tank. After lowering each ground wire directly below from the tank 5 using the ground wires 8 and 9,
It is connected to the main grounding line 10 forming a grounding network. Moreover, the circuit breaker tank 5 and the current transformer tank 4 are insulated from the disconnector tank 3.

Note that the reference numeral 11 is a grounding wire of an adjacent tank.

In such a conventional structure, if a 200 mm ² copper stranded wire (outer diameter 18.2 mm) is used as the ground wire, the ground wire length is 5 m, the resistance is 0.55 mr, and the inductive reactance (60
Hz) 2.4mr, impedance 2.46mr.

On the other hand, since the tank has a large outer diameter of 1000mm, the resistance is 0.1mr and the inductive reactance (60Hz)
0.75 mr and impedance of 0.76 mr, which are smaller values than copper stranded wires, and the induced current flowing in the main grounding wire 10 can be easily shunted to the tank.

Furthermore, the mutual inductance is greatest between the tank and the main circuit, so the tank has an induced current i ₁
The largest induced voltage is generated in the direction of disconnector tank 1 → bushing tank 2 → disconnector tank 3 →
An induced current is generated in the closed loop of grounding wire 7 → main grounding wire 10 → grounding wire 6.

The induced current flowing in the tank is added because the shunted portion of the induced current _i1 flowing in the main grounding wire 10 to the tank and the induced current generated in the closed loop are in the same direction. In the main grounding wire 10 while the wire 6 is connected, the induced current i ₁ that flows into the main grounding wire 10 and the induced current generated in the closed loop are subtracted because their directions are opposite. , the current will be small in this part. The same applies to the closed loop including the circuit breaker tank 5. Therefore, the induced current i ₁ is as shown in the figure, main grounding wire 10 → grounding wire 6 → disconnector tank 1 → bushing tank 2 →
Disconnector tank 3 → ground wire 7 → main ground wire 10 → ground wire 8 → circuit breaker tank 5 → ground wire 9 → main ground wire 10
It flows through the circuit → ground wire 11 → another disconnector tank. In addition, a closed loop is formed by the main grounding wire 10, grounding wires 6, 7, disconnector tanks 1, 3, and bushing tank 2, and a closed loop is formed by the main grounding wire 10, grounding wires 8, 9, and circuit breaker tank 5. Induced currents also flow in the closed loops. Therefore, gas-insulated electrical equipment with conventional grounding wire configurations have the disadvantage that the main grounding wire may overheat and melt, and overheating of the exposed grounding wire may pose a safety hazard. . Furthermore, since an induced current flows through the tank, the temperature of the tank and the bus bar increases to a high degree.

The present invention eliminates the drawbacks of the conventional grounding wire configuration, prevents the induced current flowing in the main grounding wire from passing through the tank, and also separates the induced current flowing in the grounding wire and the induced current flowing in the main grounding wire. The object is to obtain a gas insulated electrical device having a ground conductor configuration with respective reduced values.

In order to achieve this object, the present invention provides a grounding wire at two or more locations of one or a plurality of electrically connected tanks, and the grounding wire is a main grounding wire that constitutes the grounding network. This is characterized in that the plurality of grounding wires are merged into one before being connected to the main grounding wire, and then connected to the main grounding wire.

The present invention will be described below with reference to the accompanying drawing, FIG. 2, which shows a gas insulated electrical device as one embodiment thereof. Note that FIG. 2 shows the same equipment arrangement as FIG. 1, and only the configuration of the grounding wire is different.

In the figure, disconnector tanks 1 and 3, bushing tank 2, current transformer tank 4, circuit breaker tank 5, main ground wire 10, and ground wire 11 of the adjacent tank are arranged in the same manner as in the conventional device. In addition, the grounding wires 6' and 7' derived from the disconnector tanks 1 and 3 are connected by a grounding wire 21 disposed near the main grounding wire 10, and the grounding wire 21
is connected to the main ground wire 10 by one ground wire 22. Similarly, the grounding wires 8' and 9' led out from the circuit breaker tank 5 are also connected by a grounding wire 23 placed near the main grounding wire 10, and the grounding wire 23 is connected to a single grounding wire. 24 connects the main ground wire 10
It is connected to the.

Since the device of the present invention has such a configuration, the disconnector tank 1→butting tank 2→disconnector tank 3→ground wire 7′→ground wire 21→ground wire 6′→disconnector tank 1 An induced current _i3 flows in the circuit, and an induced current i4 flows in the circuit breaker tank 5→ground wire 9'→ground wire 23→ground wire 8'→breaker tank 5, and the induced current _i4 flows in the main circuit current. current i ₂
flows.

The inductive circuit constructed in this way and composed of the main grounding wire 10 has a large impedance main grounding wire 1.
0 only, and there is no impedance drop due to branching from the tank as in the past, so the induced current flowing through the main grounding wire 10 is reduced, and the induction circuit flowing through the tank is only connected to the main grounding wire at one point. Since the wires are not connected, the induced current flowing through the main grounding wire 10 does not flow into the closed circuit, and therefore, this amount is not added to the induced current of the grounding wire, so that the induced current decreases.

Further, the present invention will be explained based on FIG. 3 of the accompanying drawings showing another embodiment.

In the figure, the same symbols as in Fig. 2 indicate the same parts as shown in Fig. 2, and the circuit breaker tank 5
The grounding wires 8'' and 9'' derived from Ground wire 2 as in the embodiment
4 connects the ground line 23' to the main ground line 10.

By doing so, the area of the circuit including the grounding wire is reduced, the amount of leakage magnetic flux penetrating by the energized conductor current is reduced, and the induced current i ₄ is reduced.

In the gas insulated electrical device of the present invention having the grounding wire configured as described above, it is possible to reduce the current induced in the grounding wire, thereby preventing overheating and melting of the grounding wire, and It is also possible to prevent the exposed ground wire from overheating, which has the effect of being extremely favorable from a safety standpoint. Furthermore, the induced current flowing through each tank is reduced, and therefore the temperature rise of the tank and the bus bar can be reduced, and as a result, each tank also has the effect of being able to be made smaller.

Although the above description has been made regarding a gas insulated electrical device having a circuit breaker tank, a disconnector tank, etc., the present invention is not limited thereto, and can also be applied to a gas insulated bus bar.

[Brief explanation of drawings]

FIG. 1 is a perspective view of an example of a conventional gas insulated electrical device, FIG. 2 is a perspective view of an embodiment of the gas insulated electrical device of the present invention, and FIG. 3 is a perspective view of another example of the gas insulated electrical device of the present invention. It is a perspective view showing an example. 1... Disconnector tank, 2... Bushing tank, 3
... Disconnector tank, 4... Current transformer tank, 5... Breaker tank, 6-9, 11, 21-24, 6'-9', 2
3', 8'', 9''...Grounding wire, 10...Main grounding wire, i ₁ to i ₄
...induced current.

Claims (1)

[Claims] 1 Gas-insulated electrical equipment in which a tank filled with insulating gas and housing electrical equipment is electrically connected to a grounding network buried on the site where the tank is installed by a grounding wire. In, 1
A grounding wire is provided at two or more locations of a plurality of tanks that are individually or electrically connected, and a grounding wire is connected to a plurality of the grounding wires before the grounding wire is connected to the main grounding wire constituting the grounding network. A gas insulated electrical device characterized in that the two are connected to the main grounding wire after merging into one wire.