Common faults of high voltage disconnectors and countermeasures

The isolating switch is a main equipment used in conjunction with the circuit breaker in the substation and transmission and distribution lines. It has a relatively important role in operation. This paper introduces the common faults and countermeasures of the isolating switch in operation.

The isolating switch, also known as the isolating knife gate, is mainly used to ensure the safety of the inspection work of the high-voltage device. Between the equipment to be repaired and other live parts, the isolating switch is used to form a sufficiently large visible air insulation interval.

Fever failure and countermeasures

Check the contact pins of the contacts and wires for poor contact. For the structure of the isolating switch, it is mainly checked whether the contact points of the top caps at both ends and the contacts or the blade contacts crimped by the spring are overheated and the post insulators are deteriorated, so that the overall temperature rises. After the fault is discovered, it should report to the dispatcher and immediately try to reduce or transfer the load and strengthen the monitoring.

If a busbar side isolating switch generates heat when the double busbar is connected, the line can be switched to another busbar. When the load is transferred to the dispatcher and the superior, the load is transferred, and then the power failure check is performed on the heat of the above-mentioned isolating switch. If there is a virgin, you can pour the load to the side mother.

If a busbar side isolating switch generates heat when the single busbar is connected, and the busbar cannot be powered off for a short time, the load must be reduced and monitoring should be strengthened. When the busbar can be powered off, it can be powered off to repair the heating isolating switch.

If the load side (line side) isolating switch generates heat during operation, the processing method is basically the same as that of single busbar wiring. For the isolation switch in the high-pressure room to generate heat, in addition to reducing the load and monitoring during the maintenance operation, ventilation and cooling measures should be taken. During power failure maintenance, the same should be done for the cause of the heat generated by the isolating switch.

Rejection failure and countermeasures

Isolation switches with higher voltage levels are operated with an electric operating mechanism. When the isolation switch of the electric operating mechanism refuses to close, it should focus on whether the contactor is moving, whether the motor rotates or not, and the operation of the transmission mechanism to distinguish the fault range and report to the dispatcher.

(1) If the contactor does not operate, it may be a control loop problem. Solution: First check the equipment number and operation sequence. If there is any error, the operation circuit is blocked by the anti-misclosure circuit. Correct the operation and correct the operation power. If the fuse is blown or the contact is bad, After the processing is normal, continue to operate and then see if there is no problem above, check the non-passage point in the loop, and continue to operate after the processing is normal.

(2) If the contactor has been operated, the problem may be that the contactor is stuck or poorly contacted, or it may be a problem with the motor. The voltage on the motor terminals should be further checked. If the voltage is abnormal, it proves to be a problem with the contactor, and vice versa.

(3) If the motor rotates, the mechanism should be suspended due to the mechanical stuck. Check the ground isolation switch first to see if it is fully pulled in place and pull it fully into position before proceeding.

If there is no such problem, check whether the motor is out of phase. After the three-phase power supply returns to normal, continue operation. If it is not a phase loss problem, you can perform manual operation to check the mechanical stuck position. If it can be eliminated, continue operation. If it still can't be solved, the operation mode should be adjusted to restore the power supply first, and then report to the higher level, and then the maintenance personnel will handle the power failure.

(1) First check whether the equipment number and operating procedures are incorrect, and check if the circuit breaker is in the disconnected position.

(2) If there is no such problem, check if the isolation switch is fully opened. Once you have fully pulled it in place, you can continue.

(3) If there is no such problem, check the mechanical stuck position. If it is not a mechanism, lack of lubricating oil, you can add oil, turn it a few times, and then close it. If it is a problem in the transmission part, it cannot be processed at one time. The operation mode should be adjusted to restore the power supply first, and then reported to the superior. When the power is off, it is handled by the maintenance personnel.

The isolation switch rejection fault detection and treatment method is basically the same as the isolation switch rejection closing fault and the treatment method. However, when the manual operation cannot be opened, it is forbidden to be pulled open. The operation mode should be adjusted to remove the fault isolation switch after operation. .

Countermeasures for stopping in the middle of operation

In the electric operation, the isolating switch automatically stops the fault midway. If the distance between the contacts is small, the arc discharge will occur for a long time, mostly due to the premature opening of the operating circuit and the poor contact in the circuit. Treatment method: When the isolation switch is pulled, if it stops in the middle, it should be quickly opened and closed manually. If it stops in the middle and must be operated when the time is tight, it should be quickly operated manually to close the isolation switch. If time permits, Quickly open the isolation switch and remove the fault before operating.

Countermeasures for closing the door

If the isolating switch is not fully seated during operation and the contact is poor, it will generate heat during operation and endanger the safe operation of the power grid and equipment. Treatment: In the event of a failure or a three-phase failure, the overlap should be opened and the compound should be repeated several times. The operation should be in accordance with the essentials and the force should be appropriate. If it is not fully fit and cannot reach the full phase of the three phases, wear insulated gloves, use insulated rods, put the three-phase contacts in place, and report to the superiors to arrange for scheduled power outages.