JPH05111119A - Gas insulation switching device - Google Patents

Abstract

PURPOSE:To provide a gas insulation switching device by which induced current can be treated without installing a special grounding switch and the reclosing of a breaker is available. CONSTITUTION:A disconnector 11 and a grounding switch 12, each being connected on the side of a primary bus 10 of a GCB 7, are so structured that they may open or close a circuit due to motor spring operation or hydraulic operation about 100-200 msec after instructed to work and only the same phase as the one at which the GCB 7 operates may work. A sequence of these operations is so structured that after the GCB 7 of a faulty phase cuts off the circuit, the disconnector 11 of the same phase opens the circuit, and then the grounding switch 12 closes the circuit and after that, the GCB 7 closes the circuit. Then, after a sustaining arc disappears, the GCB 7 opens the circuit and cuts off induced current and then, after the grounding switch opens the circuit and the disconnector 11 closes the circuit, the GCB 7 closes the circuit again.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas-insulated switch which has been improved so that the system can be quickly restored when an accident such as a ground fault occurs in an overhead power transmission line and an accident current flows. It relates to the device.

[0002]

2. Description of the Related Art Recent power transmission systems are going from ultra high voltage class of 500 KV to ultra high voltage class of 725 KV and 1000 KV. In such a power transmission system, the distance from other lines that are installed in parallel or transmission lines of the same phase in other phases is larger than the voltage as it becomes the ultra-high voltage class mentioned above due to structural restrictions such as towers. There is a fear that it will not be taken.

Normally, up to about 500 KV, when a ground fault occurs due to a lightning strike, each circuit breaker installed at the substation at both ends of the transmission line of each line is shut off to eliminate the ground fault current. it can.

However, in the ultra-high voltage class of 725 KV to 1000 KV, as described above, since the distance from another line or the transmission line of another phase of the same line is small and the voltage is high, the transmission line of another healthy line is If the circuit breakers at the substations at both ends of the accident point are simply interrupted due to the induced current from, the induced current will continue to flow in the transmission line as if the accident current remained and the arc continued. Therefore, when the circuit breaker is turned on, the circuit breaks again. Therefore, in order for the reclosing operation to be successful, it is necessary to extinguish the continuous arc before reclosing.

As one of the methods, after the fault current is cut off by a circuit breaker, a high-speed grounding switch provided on the line side is turned on,
There is a method in which the induced current flowing in the continuous arc is extinguished by commutating to the high-speed grounding switch, and then the high-speed grounding switch is opened to interrupt the induction current. As a result, the ground fault arc on the line can be completely removed, and the phase in which the accident has occurred can be returned to the operating state by reclosing the circuit breaker.

FIG. 4 is a single wire connection diagram showing an example of a conventional gas-insulated switchgear, and FIG. 5 is a side view in the case where it is constituted by a gas-insulated device. That is, as shown in FIG.
A high-speed grounding switch 4 is additionally provided on the transmission line side of the line-side disconnector 5 of a normal line circuit.

The operation and responsibilities of this high-speed grounding switch 4 will be described below. When a ground fault occurs on the overhead power transmission line 1, an excessive fault current flows through this line, and a gas circuit breaker (hereinafter, referred to as GCB) 7 shuts it off immediately. However, when the transmission voltage rises from 725 KV to 1000 KV or more, a large induced current of several 1000 A from another phase and another line continues to flow at the accident point, so that the arc continues and the normal GCB reclosing operation occurs. However, since it trips again, the system cannot be utilized.

Therefore, after the GCB 7 first interrupts the fault current, the high-speed grounding switch 4 is turned on to commute the continuous induction current at the fault point and extinguish the continuous arc at the fault point. After that, the high-speed grounding switch 4 cuts off this induced current and completely cancels the grounded state of the power transmission line. And GC
By the reclosing of B, the power transmission line which caused the ground fault can be utilized and the system can be restored to the original state.

[0009]

However, the high-speed grounding switch 4 selects not only the accident phase according to the operation of the GCB 7 but also closes and opens the circuit within about 1 second.
You will be tasked with turning on and off the induced current. Further, the making current is a large current exceeding about 3000 A, and even when the current is cut off, the current must be cut off and the recovery voltage must endure a very high voltage of about 600 KVp. This interruption duty is the induction current switching duty 1000A- which has been conventionally imposed on the line side grounding switch.
This is an order of magnitude more demanding than 70 KVrms, and it is difficult to construct a device with the conventional grounding switch concept, and a contact and mechanism equivalent to a circuit breaker are required.

For this reason, the high-speed grounding switch becomes a very large device, and not only the layout is enlarged, but also the operation is performed by interlocking with operations such as selective cutoff of the GCB, reclosing operation, and the like. In mechanically configuring the interlock condition, disposing the high-speed grounding switch 4 at a position distant from the GCB requires a long mechanism for connecting the two, which is necessary for reliability and maintenance inspection of the equipment. Is not preferable. This is a serious problem for substations of ultra-high voltage class of 725 KV or 1000 KV.

FIG. 6 is a single wire connection diagram showing another example of a conventional gas-insulated switchgear, and FIG. 7 is a side view of the gas-insulated device when it is constructed. That is, in the gas-insulated switchgear shown in FIG.
And the line side disconnecting switch 5. By arranging the high-speed grounding switch 4 on the transmission line side of the GCB 7 as described above, the same effect as that of the gas-insulated switchgear shown in FIG. 4 can be obtained, and the high-speed grounding switch 4 can be placed closer to the GCB 7. Therefore, there is an advantage that a long mechanism for connecting the two is not required unlike the gas insulated switchgear shown in FIG.

However, even in the above-described improved example, the grounding switch requires a breaking responsibility equivalent to that of a circuit breaker.
The high-speed grounding switch becomes a very large device, and it is necessary not only to make the layout large, but also to operate by interlocking with operations such as selective cutoff of GCB and reclosing operation.

The present invention has been proposed in order to solve the above-mentioned drawbacks of the prior art, and its purpose is not to require a special grounding switch, but to cope only with the operation mode and to prevent a transmission line accident. An object of the present invention is to provide a highly reliable gas-insulated switchgear capable of processing an induced current that sustains an arc at a point and enabling reclosing of a circuit breaker.

[0014]

DISCLOSURE OF THE INVENTION The present invention is a gas-insulated switchgear in which a ground switch and a disconnector are connected to the main bus side of a circuit breaker provided in a transmission line, and the circuit breaker has an accident. When the phase is selectively cut off, the earthing switch and the disconnecting switch are also configured to perform the switching operation by selecting the same phase, and the circuit breaker prevents the induced current that keeps the arc at the accident point. The operation sequence of the circuit breaker, the earthing switch, and the disconnecting switch is configured so that they can be processed.

[0015]

According to the gas-insulated switchgear of the present invention, it is possible to process the induced current flowing in the continuous arc at the accident point by using the circuit breaker which has been conventionally incorporated and used in the line circuit. There is no need to newly develop a switch. In addition, since the object can be achieved only by the device that constitutes the conventional line circuit, the installation space of the device does not increase. Furthermore, 1000K
A class V circuit breaker usually has two or more circuit break points, has sufficient circuit breaking performance, and has high-speed repetitive operation built in from the beginning, so the circuit breaker is used to make and break current. By doing so, the reliability of the gas insulated switchgear can be greatly improved.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be specifically described below with reference to FIGS. The same members as those of the conventional type shown in FIGS. 4 to 7 are designated by the same reference numerals, and the description thereof will be omitted.

In this embodiment, as shown in FIG.
The disconnecting switch 11 and the grounding switch 12 connected to the main bus side of the GCB 7 are configured so that they can be opened or closed in about 100 to 200 msec after an operation command is issued by an electric spring operation or a hydraulic operation. Has been done. In addition, the disconnecting switch 11 and the grounding switch 12 are also configured to operate only in the same phase in accordance with the phase in which the GCB 7 is cut off or turned on.

Further, in the order of operation, an accident such as a ground fault occurs in the transmission line, a short-circuit current flows, the GCB 7 in the accident phase shuts off, and then the disconnector 11 in the same phase opens. The ground switch 12 is configured to be closed, and then the GCB 7 is configured to be closed. And about 500 mse
After c to 800 msec, the induced current flowing in the continuous arc at the accident point is commutated to the ground through the GCB 7 and the grounding switch 12, and after the continuous arc disappears, the GCB 7 opens to cut off this induced current. The operation sequence is configured so that the ground switch 12 opens and the disconnector 11 closes, and then the GCB 7 closes again.

The disconnector 11 and the grounding switch 12 are also provided.
In addition to the above-mentioned operation mode at the time of a line accident, the one is configured to enable an operation mode of only the disconnecting switch or only the grounding switch in a three-phase operation by one command for normal operation.

Next, an example of the structure of the disconnecting switch 11 and the grounding switch 12 will be described with reference to FIG. That is, tank 2
The disconnector movable side conductor 23 fixedly supported by the insulating spacer 22 and the main busbar conductor 25 supporting the fixed side contact portion 24 are accommodated in the housing 1. Further, the disconnector movable side contactor 2
6 is configured to be opened and closed by an operating device 30 provided outside through an insulating rod 27, a lever 28, and a main shaft 29 to open and close between the disconnector movable side contact portion 31 and the fixed side contact portion 24. There is.

Further, a fixed side contact portion 32 of the earthing switch is provided at a part of the disconnecting switch movable side conductor 23, and at a position opposed to the fixed side contact portion 32, a lever 34 and a main shaft 35 are interposed.
The movable rod 33 is configured to be opened and closed by an operating device 36. In addition, the operation sequence described above is
It is performed by an electric command etc. to the operating device, but in order to be able to operate immediately after the command, in the case of electric spring operation, the drive spring is put in a standby state for energy storage, and in the case of hydraulic operation method, pressure is applied. Keep it in a state. These are similar to electric spring operating devices or hydraulic operating devices for gas circuit breakers.

The gas-insulated switchgear of this embodiment having such a structure operates as described below. That is, when a ground fault occurs in the overhead power transmission line 1 due to a lightning strike or the like, first, the fault current is selectively cut off by the GCB 7. At this time, at the ground fault accident point, an induced current flows from a healthy other phase or another line, and the ground fault arc continues. Then, after the circuit breaker is cut off, the disconnector 11 is opened and the main bus 10 side opens the GCB.
After disconnecting 7, the grounding switch 12 is turned on. In this case, the busbar that the grounding switch 12 turns on is not the line
Since it is disconnected at 7 and the main bus side is disconnected at the disconnector 11, no current flows at the time of turning on.

Then, the GCB 7 is charged. At this time, an induced current of about 3500 A flows as the input current, but
B7 has a short-circuit current of 50 KA, and the grounding switch 12 has a short-time energizing performance of 50 KA or more in a closed state. Therefore, this induced current is not a problem.

Since the induced current is diverted to the GCB7, the continuous arc at the accident point is extinguished and the line is normally restored. Therefore, after about 500 to 800 msec, the time required for the arc to extinguish is reduced. After the elapse, the GCB7 is opened. At this time, the induced current is about 3500A-280KV
Will be shut off, but this GCB7 is 1000KV
Since it is applied to the system and has the ability to cut off the fault current of 50 KA, this level of induced current can be cut off without any problem.

After the circuit of the GCB 7 is opened, the earthing switch 12 is opened, the disconnector 11 is closed, and then the GCB 7 is closed again, so that the power transmission line can be restored to the original system and utilized. In addition, since the operating time of the disconnecting switch 11 and the grounding switch 12 is about 100 ms to 200 ms, it takes about 1 to about 1 ms from the opening of the GCB to the restoration of the system after the accident.
This is possible in a short time of about 1.5 seconds or less, and the influence on the system can be minimized.

As described above, according to the present embodiment, the duty corresponding to the circuit breaker for making and breaking the induced current flowing in the continuous arc at the accident point is conventionally used by being incorporated in the line circuit. It can be handled by a circuit breaker, eliminating the need to develop a special grounding switch. In addition, the purpose can be achieved only with the devices that make up the conventional line circuit, and it is not necessary to arrange other devices, so the installation space is significantly larger than when using a high-speed grounding switch. Can be reduced.

Furthermore, a 1000KV class circuit breaker is usually 2
Since it has a breaking point above the point, there is ample margin for breaking performance, and high-speed repetitive operation is built in from the beginning,
Since the circuit breaker is used to perform the operation of turning on / off the current, it is possible to provide a more reliable gas insulated switchgear.

[0028]

As described above, according to the present invention, when the circuit breaker used in the transmission line selectively cuts off the accident phase, the grounding switch and the disconnecting switch also select the same phase. It is configured to perform opening / closing operation, and by the circuit breaker,
By configuring the operation sequence of the circuit breaker, grounding switch and disconnecting switch so that the induced current that sustains the arc at the accident point can be processed, no special grounding switch is required and only the operation mode is supported. Thus, it is possible to provide a highly reliable gas-insulated switchgear capable of processing the induced current and enabling the circuit breaker to be closed again.

[Brief description of drawings]

FIG. 1 is a single wire connection diagram showing an example of a gas-insulated switchgear according to the present invention.

FIG. 2 is a side view of the single wire connection diagram of FIG. 1 when configured with a gas insulation device.

FIG. 3 is a structural diagram showing an example of a busbar-side disconnector and a grounding switch used in the gas-insulated switchgear of the present invention.

[Fig. 4] Single wire connection diagram of a conventional gas insulated switchgear

FIG. 5 is a side view of the single wire connection diagram of FIG. 4 configured with a gas insulation device.

FIG. 6 is a single wire connection diagram of a conventional gas insulated switchgear.

FIG. 7 is a side view of the single wire connection diagram of FIG. 6 configured with a gas-insulated switchgear.

[Explanation of symbols]

 1 ... Overhead transmission line 2 ... Bushing 3 ... Line side grounding switch 4 ... High speed grounding switch 5 ... Line side disconnecting switch 6 ... Grounding switch 7 ... Gas circuit breaker (GCB) 8 ... Grounding switch 9 ... Bus side disconnecting Switch 10 ... Main bus 11 ... Bus-side disconnector 12 ... Ground switch

Claims (1)

[Claims] 1. A gas-insulated switchgear in which a grounding switch and a disconnecting switch are connected to the main bus side of a circuit breaker provided in a transmission line circuit, when the circuit breaker selectively interrupts an accident phase, The earthing switch and the disconnecting switch are also configured to perform the switching operation by selecting the same phase, and the circuit breaker can process the induced current that keeps the arc at the accident point. A gas-insulated switchgear comprising an operation sequence of a ground switch and a disconnector.