JPH03141523A - Switching device - Google Patents

Abstract

PURPOSE:To detect deterioration of induction current switching performance of a grounding switch for a line speedily and improve the safety by disposing a current transformer for detecting an induction current in a grounding line circuit where the grounding switch for a line having induction current switching specifications is inserted. CONSTITUTION:A grounding line circuit 4A, 4B where a grounding switch 5A, 5B for each line having induction current switching specifications is inserted is provided with a current transformer 10A, 10B for detecting an induction current, so an electromagnetic induction current and an electrostatic induction current are detected by the current transformer 10A, 10B. A relay 11A, 11B is operated based on an output of the current transformer 10A, 10B and a switching condition of the grounding switch 5A, 5B for a line, and an abnormality alarm, etc., for showing occurrence of a defective at the grounding switch 5A, 5B is given corresponding to the action of the relay 11A, 11B.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a switchgear such as 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 switchgear IA and IB such as gas insulated switchgear, and the steel tower 2A,
Line 3a attached to 2B.

Power is supplied from 3b. Each switchgear IA, I
Track grounding switches 5A and 5B are inserted into the grounding line circuits 4A and 4B of B, respectively, and when inspecting and maintaining equipment such as circuit breakers 6A and 6B, and the tracks, etc., for work safety. The line grounding switches 5A and 5B are closed.

For example, the line 3a side is in regular operation, and the line 3b
When the line 3a is stopped, an induced voltage is induced in the line 3b from the line 3a. At this time, for example, the track grounding switch 5A.

5B are both closed, an electromagnetic induction current will flow between the line 3b and the ground.

In this state, for example, when attempting to open the line grounding switch 5A, the electromagnetic induction current must be cut off. 5B is in the closed state, a voltage is generated in the line 3b due to electrostatic induction from the line 3a side, so there is a ground line circuit 4B between the line 3b and the ground.
An electrostatically induced current flows through the Therefore, when the line grounding switch 5B is opened, the electrostatic induced current must be cut off.

These line grounding switches 5A and 5B are required to have electromagnetic induction current switching responsibilities and electrostatic induction current switching responsibilities.

5B, for example, a suction type, a buffer type, etc. having induced current switching specifications are applied.

[Problem to be solved by the invention]

However, if some kind of malfunction occurs in the track grounding switches 5A and 5B, or if they reach the end of their service life, and they are no longer able to fully achieve the induced current switching function, the track grounding switches 5A and 5B Even if 5A and 5B are operated, the induced current cannot be interrupted, causing problems such as arcing. The occurrence of such defects cannot be seen from the outside, especially in the case of gas-insulated switchgear, and may result in major accidents such as welding or rupture. Also, grounding switch 5A for tracks.

With 5B not open for sustaining the arc,
If the circuit breakers 6A and 6B are closed, a ground fault will occur.

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

(Means for Solving the Problem) A switchgear according to claim (+) includes a current transformer for detecting induced current arranged in a grounding line circuit in which a line grounding switch having induced current switching specifications is inserted. The switchgear according to claim (2) is characterized in that, in the switchgear according to claim (1), a current transformer is connected after a certain period of time after the opening command signal of the line grounding switch is output. It is designed to generate an abnormality alarm in response to the induced current of the device.

The switchgear according to claim (3) is characterized by claim (1) or (
2) In the switchgear described above, the line grounding switch is turned on again in response to the induced current of the connected current transformer after a certain period of time after the opening command signal of the line grounding switch is output. It is something.

[Effect]

According to the configuration of the present invention, the induced current flowing through the ground line circuit when the line grounding switch is in the closed state is detected by the current transformer disposed in the ground line circuit. If an induced current is detected in the current transformer when the line grounding switch is opened, it is considered that an arc is continuing in the line grounding switch, and this Deterioration in the induced current switching performance of a line grounding switch can be detected using this method.

〔Example〕

FIG. 1 is a system wiring diagram showing the basic configuration of a switchgear according to an embodiment of the present invention. In FIG. 1, parts corresponding to those shown in FIG. 4 described above are designated by the same reference numerals. In this embodiment, each grounding line circuit 4A, 4B in which each line grounding switch 5A, 5B having an induced current switching specification is inserted has an induction ii! A current transformer 10A and IOB for current galvanization are provided, and the electromagnetic induced current and electrostatic induced current are detected by the current transformer 10A and IOB.

Current transformer 10A, IOB output and line grounding switch 5A,
Based on each open/close state of 5B, relays 11A and IIB
operates, and in response to the operation of the relays 11A and IIB, an abnormality alarm is issued indicating that a malfunction has occurred in the line grounding switches 5A and 5B.

FIG. 2 is a timing chart for explaining the operation, and shows, for example, the operation on the switching device IA side. Figure 2 (1) shows the auxiliary contact (
(not shown), and FIG. 2 (2) shows the operation of the current transformer 10.
It shows the current flowing through A.

When the line grounding switch 5A is closed during the period from time t1, an induced IT current flowing through the ground line circuit 4A is detected by the current transformer 10A. Then, at time t2, when the track grounding switch 5A is opened, no induced current flows through the grounding line circuit 4A, so the current in the current transformer 10A also becomes zero. Such an operation is an operation when the opening/closing operation of the line grounding switch 5A is performed normally.

FIG. 3 shows the operation when the line grounding switch 5A is no longer able to cut off the induced current well due to the end of its lifespan or the like. FIG. 3(1) shows the operation of the above-mentioned auxiliary switch included in the line grounding switch 5A, and FIG.
2) shows the control current for controlling the opening and closing of the line grounding switch 5A, and FIG. 3 (3) shows the current flowing through the current transformer 10A.

When the close command control current C1 is applied to the line grounding switch 5A during the period from time Tl, the auxiliary switch becomes open at time T2, which is slightly after time T1. That is, at this time T2, the line grounding switch 5A is in the closed state. As a result, an induced current due to electromagnetic induction or electrostatic induction flows through the ground line circuit 4A, and a current flows through the current transformer 10A due to this induced current.

When the open command control current C2 is applied to the line grounding switch 5A during the period starting from time T3, the auxiliary switch becomes open at time T4, which is a little later than time T3. Therefore, during normal operation, the line grounding switch 5A is in the open state at this time T4, but if the induced current interrupting performance has deteriorated, due to the continuation of the arc caused by the induced current, The ground line circuit 4 is not opened, so that current flows through the current transformer 10A as indicated by reference numeral i1 even during the period after time T4.

In this way, if the arc continues to occur in the line grounding switch 5A, there is a risk of developing into a major accident as described above, but in this embodiment, the closing command control current C2 is applied. If current flows through the current transformer 10A even at time T5, which is a predetermined time ΔT elapsed from time T3, relay IIA is operated, and in response to the operation of relay 11A, the close command control current is connected to the track ground. The power is then applied again to the switch 5A. As a result, the line 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 abnormality alarm is issued indicating that the induced current in the line grounding switch 5A is not properly interrupted. Upon receiving this abnormality alarm, the operator promptly inspects and repairs the track grounding switch 5A. The configuration and operation described above are the same on the switching device IB side.

As described above, in the switchgear IA and IB of this embodiment, the grounding line circuit 4A, in which the line grounding switches 5A and 5B are inserted,
4B is provided with a current transformer 10A and IOB, and this current transformer 10
By detecting the induced current at A and IOB, deterioration of the induced current interrupting performance of the line grounding switches 5A and 5B is monitored. If an arc or the like occurs internally due to deterioration of the induced current interrupting performance, the line grounding switches 5A and 5B are immediately closed to extinguish the internal arc and prevent a major accident. In addition to preventing this from occurring, the system also issues an abnormality alarm indicating that the induced current interrupting performance has deteriorated, prompting the operator to perform inspection and repair. In this way, according to this embodiment, the safety of the switchgear is significantly improved.

[Effects of the Invention] As described above, according to the switching device of the present invention, deterioration in the induced current switching performance of the line grounding switch can be detected. Additionally, in response to this, measures can be taken to extinguish the internal arc by, for example, issuing an abnormality alarm or promptly closing the track grounding switch, thereby greatly increasing safety. It will be improved.

[Brief explanation of the drawing]

Fig. 1 is a system wiring diagram showing how power is transmitted between substations including a switchgear according to an embodiment of the present invention, Figs. 2 and 3 are timing charts showing its operation, and Fig. 4 shows a conventional technology. It is a system wiring diagram shown.

Claims (3)

[Claims] (1) A switching device characterized in that a current transformer for detecting induced current is disposed in a grounding line circuit in which a line grounding switch having induced current switching specifications is inserted. (2) The switchgear according to claim (1), wherein the abnormality alarm is generated in response to the induced current of a connected current transformer after a certain period of time after the opening command signal of the line grounding switch is output. . (3) Claim (1) in which the line grounding switch is turned on again in response to an induced current in a connected current transformer after a certain period of time after the line grounding switch opening command signal is output. Or the opening/closing device described in (2).