JP2940020B2 - Gas insulated switchgear - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a gas insulated switchgear.

[Conventional technology]

FIG. 4 is a system wiring diagram showing a simplified state of power transmission between substations. Each substation is equipped with a gas-insulated switchgear 1A, 1B, respectively, and a circuit 3 attached to the towers 2A, 2B.
Power is supplied from a and 3b. Each gas insulated switchgear
1A and 1B ground line circuits 4A and 4B have line ground switches respectively.
5A and 5B are interposed, and when inspecting and caring for devices such as the circuit breakers 6A and 6B and the tracks, the track grounding switches 5A and 5B are closed for work safety.

For example, when the line 3a is operating normally and the line 3b is stopped, an induced voltage is induced in the line 3b by induction from the line 3a. At this time, if, for example, both the line grounding switches 5A and 5B are closed, the electromagnetically induced current flows between the line 3b and the ground. In this state, for example, when the track grounding switch 5A is to be opened, the electromagnetic induction current must be cut off. When the line grounding switch 5A is open and the line grounding switch 5B is closed, a voltage is generated in the line 3b due to electrostatic induction from the line 3a. An electrostatic induction current flows between 3b and the ground via the ground line circuit 4B. Therefore, grounding switch for track
When opening 5B, the electrostatic induction current must be cut off.

Since such line grounding switches 5A and 5B are required to have an electromagnetic induction current switching duty and an electrostatic induction current switching duty,
For example, suction type,
Those having an inductive current switching specification such as a puffer type are applied.

[Problems to be solved by the invention]

However, some trouble occurs in the grounding switches 5A and 5B for the track, or when they reach the end of their life,
If the induction current switching function cannot be sufficiently achieved, the induction current cannot be cut off even if the line ground switches 5A and 5B are operated, and arcing may occur. Failure occurs. The occurrence of such a defect
In the case of a gas insulated switchgear, it cannot be known from the external appearance, and as a result, a major accident such as erosion or rupture may occur. Further, if the circuit breakers 6A and 6B are closed in a state where the track grounding switches 5A and 5B are not opened to maintain the arc, a ground fault will occur.

An object of the present invention is to solve the above-mentioned technical problems and to provide a gas-insulated switchgear having significantly improved safety.

[Means for solving the problem]

The gas insulated switchgear of the present invention is a gas insulated switchgear provided with a grounding switch for a line having an inductive current switching specification. An abnormal alarm is issued in response to the detection current of the induced current detection current transformer inserted in the line, and the line grounding switch is turned on again.

[Action]

According to the configuration of the present invention, the induced current flowing in the ground line circuit when the line grounding switch is closed is detected by the current transformer arranged in the ground line circuit. If the induced current is detected in the current transformer when the line earthing switch is in the open state, it is considered that the arc is sustained in the line earthing switch. By using this, it is possible to detect the deterioration of the induced current switching performance of the line ground switch. At this time, since an abnormality alarm is issued in response to the detection current of the induced current detection current transformer inserted into the ground wire circuit, the operator can be prompted for inspection and repair. In addition, since the track grounding switch is turned on again, the arc inside the track grounding switch is extinguished, thereby preventing the occurrence of a major accident.

〔Example〕

FIG. 1 is a system wiring diagram showing a basic configuration of a gas insulated switchgear according to one embodiment of the present invention. In FIG. 1, parts corresponding to the respective parts shown in FIG. 4 are given the same reference numerals. In this embodiment, the current transformers 10A and 10B for detecting the induced current are provided in the respective ground line circuits 4A and 4B in which the respective grounding switches 5A and 5B for the lines having the induced current switching specification are inserted. The current transformers 10A and 10B detect the electromagnetic induction current and the electrostatic induction current.

The relays 11A and 11B operate based on the outputs of the current transformers 10A and 10B and the open / close states of the line grounding switches 5A and 5B, and the line grounding switches respond to the operation of the relays 11A and 11B. An abnormal alarm or the like indicating that a failure has occurred in 5A and 5B is performed.

FIG. 2 is a timing chart for explaining the operation, for example, the operation on the gas insulated switchgear 1A side. FIG. 2A shows the operation of an auxiliary contact (not shown) provided in the line grounding switch 5A, and FIG. 2B shows the current flowing through the current transformer 10A. When the line grounding switch 5A is closed during the period from time t1, an induced current flowing through the ground line circuit 4A in the current transformer 10A is detected. Then, at time t2, when the line grounding switch 5A is opened, no induced current flows through the grounding line circuit 4A.
The current of 10A also becomes zero. Such an operation is an operation in the case where the switching operation of the line grounding switch 5A is normally performed.

FIG. 3 shows the operation when the induced current cannot be cut off satisfactorily due to the service life of the line grounding switch 5A. Fig. 3 (1) is a grounding switch for railway
5A shows the operation of the above-mentioned auxiliary switch provided in 5A, FIG. 3 (2) shows a control current for controlling the switching of the line grounding switch 5A, and FIG. 3 (3) shows a current flowing through the current transformer 10A. Is shown.

When the closing command control current C1 is given to the line grounding switch 5A during the period from time T1, the time slightly after this time T1
At T2, the auxiliary switch is closed. That is,
At this time T2, the line grounding switch 5A is in a closed state.Thus, an induced current due to electromagnetic induction or electrostatic induction flows through the ground line circuit 4A, and due to this induced current, the current transformer 10A Current will flow.

When the open command control current C2 is given to the line grounding switch 5A during the period from time T3, the time slightly after this time T3
At T4, the auxiliary switch is opened. Therefore, at the time of normal operation, at this time T4, the line grounding switch 5A is in the open state, but when the induced current interruption performance is deteriorated, due to the continuation of the arc generated by the induced current, The ground line circuit 4 is not opened. Therefore, a current flows through the current transformer 10A even during a period after the time T4, as indicated by the reference numeral l1.

As described above, if the state in which the arc is generated in the line grounding switch 5A is continued, there is a possibility that the above-described large accident may occur, but in this embodiment, the close command control current C2 is given. Time when a predetermined time ΔT has elapsed from time T3
When a current flows through the current transformer 10A also at T5, the relay 11A is operated, and in response to the operation of the relay 11A, the close command control current is again supplied to the line grounding switch 5A. As a result, the track grounding switch 5A is closed and the arc is extinguished, thereby preventing a major accident. Further, in response to the operation of the relay 11A, an abnormal alarm indicating that the induction current in the line grounding switch 5A has not been properly interrupted is issued. Upon receiving this abnormal alarm, the operator immediately inspects and checks the track grounding switch 5A.
It will be repaired. The above-described configuration and operation are the same on the gas insulated switchgear 1B side.

As described above, in the gas insulated switchgear 1A, 1B of this embodiment, the ground wire circuits 4A, 4B inserted through the line grounding switches 5A, 5B.
The current transformers 10A and 10B are provided in the power supply and the induced currents are detected by the current transformers 10A and 10B to monitor the deterioration of the induced current cutoff performance of the line grounding switches 5A and 5B. If an arc or the like is generated inside due to the deterioration of the induced current interruption performance, the grounding switches 5A and 5B for the line are quickly closed to extinguish these internal arcs and cause a major accident. To prevent the occurrence of abnormalities and give an abnormal alarm indicating that the induced current interrupting performance has deteriorated,
I try to encourage repairs. Thus, according to this embodiment, the safety of the gas insulated switchgear is significantly improved.

〔The invention's effect〕

As described above, according to the gas insulated switchgear of the present invention,
Deterioration of the induced current switching performance of the line ground switch is detected. In response to this, it is possible to take measures to eliminate the internal arc by issuing an alarm, etc., or immediately closing the track grounding switch, thereby significantly improving safety. Will be done.

[Brief description of the drawings]

FIG. 1 is a system wiring diagram showing a state of power transmission between substations including a gas insulated switchgear according to one embodiment of the present invention, FIGS. 2 and 3 are timing charts showing the operation thereof, and FIG. It is a system wiring diagram which shows a technique. 1A, 1B …… Gas insulated switchgear, 3a, 3b …… Line, 4A, 4B…
… Ground wire circuit, 5A, 5B …… Ground switch for line, 10A, 10B…
…Current transformer

Claims (1)

(57) [Claims] 1. A gas insulated switchgear provided with a grounding switch for a line having a dielectric current switching specification, wherein the gasket is inserted into a grounding line circuit a predetermined time after an open command signal is output to the grounding switch for a line. A gas-insulated switchgear, wherein an abnormal alarm is issued in response to the detection current of the induced current detection current transformer, and the line grounding switch is turned on again.