JPH0159804B2 - - 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, and are connected to each other by grounding wires 6 and 7, and The grounding lines 8 and 9 are connected to the main grounding line 10 constituting a grounding network from the tank 5 through grounding lines 8 and 9. In addition, the circuit breaker tank 5 and the current transformer tank 4
The disconnect switch is insulated from the tank.

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

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

On the other hand, since the tank has a large outer diameter of 1000mm, the resistance is 0.1mΩ and the inductive reactance (60Hz)
The impedance is 0.75 mΩ and the impedance is 0.76 mΩ, which is smaller than that of a copper stranded wire, and the induced current flowing in the main grounding wire 10 is 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→butting tank 2→disconnector tank 3→grounding wire 7→main grounding wire 10→grounding wire 8 → Breaker tank 5 → Ground wire 9 → Main ground wire 10 →
It flows through the circuit from ground wire 11 to another disconnector tank. In addition, the main grounding wire 10 and the grounding wire 6,
7, and also in the closed loop formed by the disconnector tanks 1 and 3 and the bushing tank 2, and in the closed loop formed by the main ground wire 10, the ground wires 8 and 9, and the circuit breaker tank 5, respectively. Therefore, gas-insulated electrical equipment with a conventional grounding wire configuration has the disadvantage that it can cause overheating and melting of the main grounding wire, and that overheating of the exposed grounding wire can be dangerous from a safety standpoint. Ta. 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 prevents the induced current flowing in the grounding wire and the induced current flowing in the main grounding wire from passing through the tank. The object is to obtain a gas insulated electrical device having a ground conductor configuration with reduced and, respectively.

In order to achieve this object, the present invention provides grounding wires at two or more locations of one or a plurality of electrically connected tanks, and constitutes the above-mentioned grounding network to which the above-mentioned grounding wires are connected. It is characterized in that the buried direction of the main grounding wire is perpendicular to the direction in which the bushings of each phase are connected, and the plurality of grounding wires are connected to the buried main grounding wire.

Hereinafter, the present invention will be explained based on FIG. 2 of the accompanying drawings, which shows a gas insulated electrical device as an 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, the disconnector tanks 1 and 3, the bushing tank 2, the current transformer tank 4, the circuit breaker tank 5, and the grounding wire 11 of the adjacent tank are arranged in the same way as in the conventional device, and The main grounding wire 21 is arranged so that its buried direction is perpendicular to the direction in which the bushings of each phase are connected, that is, the axial direction of the disconnector tanks 1 and 3. As shown in FIG.
Connected.

Since the grounding wire of the device of the present invention is configured in this way, the induced current flowing through the grounding wire is from disconnector tank 1 → bushing tank 2 → disconnector tank 3.
→ Earthing wire 7' → Main earthing wire 21 → Earthing wire 6' → Induced current i ₂ flows in the closed circuit called circuit breaker tank 1, and circuit breaker tank 5 → Earthing wire 9' → Earthing wire 8' → Circuit breaker An induced current _i3 flows in a closed circuit called tank 5,
Furthermore, an induced current i ₄ flows through the main grounding line 21 .

Since the grounding wire and the main grounding wire are configured in this way, and the induced current flows in each of them, the induced current _i4 flowing in the main grounding wire does not flow through the tank, and therefore,
The induction circuit consists only of the main grounding wire, which has a high impedance, and the impedance becomes large. There are many parts that are separated from the main circuit, and furthermore, the main circuit and the main ground wire are in a right-angled relationship (in the case of a right-angled relationship, the mutual inductance is zero). In addition, because the main grounding wire is buried in a direction perpendicular to the direction in which the bushings run, the direction of the current flowing in the main circuit (current transformer tank) that is parallel to the main grounding wire changes alternately. The inductance is canceled out and reduced, the induced voltage in the main ground line due to the main circuit current is reduced, and the induced current flowing in the main ground line is reduced.

On the other hand, disconnector tank 1 → bushing tank 2 →
The induced current flowing in the closed loop of disconnector tank 3→ground wire 7′→main ground wire 21→ground wire 6′ is caused by the branching of the current flowing through the main ground wire into this closed loop between the ground wire 6′ and the ground wire 7′. Because the length of the main grounding wire connected to it is short, the current flowing through the main grounding wire itself is small.
The induced current in the closed loop is reduced because it is not added to the shunt of the main ground line current as in the conventional case.

As a result, the impedance increases, and the induced current i ₄ flowing through the main grounding wire 21 is reduced compared to the conventional case.Moreover, the induced current flowing through the main grounding wire 21 does not flow into each of the grounding wires 6' to 9'. The induced current in the ground wires 6'-9' is also reduced.

Next, FIG. 3 of the accompanying drawings shows an embodiment of a three-phase separated type π-type gas insulated electric device to which the present invention is applied, and this main grounding wire 21 is connected in the direction in which the bushings in each phase are connected. It is installed in a right angle direction, and the grounding wire of each tank is connected to this main grounding wire 21'.
By connecting the ground wires 6' to
The induced current flowing through 9' also decreases.

In the gas-insulated electrical device of the present invention having a grounding wire configured as described above, it is possible to reduce the current induced in the grounding wire and the main grounding wire, thereby preventing overheating and fusing of the grounding wire. At the same time, overheating of the exposed ground wire can also be prevented, which has the effect of being extremely favorable from a safety standpoint. In addition, the induced current flowing through the 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 three-phase separation type π to which the present invention is applied. 1 is an external perspective view of an embodiment of a gas-insulated electrical device; FIG. 1...Disconnector tank, 2...Butching tank, 3
... Disconnector tank, 4... Current transformer tank, 5... Breaker tank, 6-9, 6'-9', 11... Ground wire, 1
0, 21, 21'...Main grounding wire, _i1 to _i4 ...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
Grounding wires are installed at two or more locations in each or a plurality of tanks that are electrically connected, and the bushing of each phase is connected to the buried direction of the main grounding wire constituting the grounding network to which the grounding wire is connected. A gas-insulated electrical device, characterized in that the plurality of grounding wires are installed perpendicular to the direction in which the grounding wires are connected, and the plurality of grounding wires are connected to the buried main grounding wire.