Improvement On Preventing Errors Of High Voltage Isolating Switches

Locking the High Voltage Disconnect Switch control wiring with the corresponding circuit breaker can effectively prevent the disconnector from pulling and closing under load. However, in the operation of the busbar side disconnector and the line side disconnector, due to human factors, the operation sequence may be reversed, which is not allowed by the switch and knife switch operation principle and is also one of the causes of accidents in the power system. In order to prevent the disconnector operation sequence from being reversed, the original disconnector control wiring of the plant and station that do not use program lock to prevent errors can be improved to prevent misoperation and reduce unnecessary accidents.
1. Principle of improvement of disconnector control locking circuit
Inserting the auxiliary contacts of the disconnector in series in the control and locking circuit of the disconnector, that is, the normally closed auxiliary contacts of the line side disconnector are connected in series in the control locking circuit of the busbar side disconnector, and the normally open auxiliary contacts of the busbar side disconnector are connected in series in the control circuit of the line side disconnector.
2. The locking wiring of the disconnector with electromagnetic lock to prevent errors (taking a single busbar feeder as an example) Figure 1 shows the original control wiring. This type of wiring can effectively prevent the disconnector from being pulled or closed under load, but it may cause the disconnector operation sequence to be reversed.
Power outage operation: After opening the circuit breaker, you can only open the line-side disconnector before opening the busbar-side disconnector.
Power supply operation: When the circuit breaker is in the disconnected position, you can only close the busbar-side disconnector before closing the line-side disconnector. This type of wiring not only prevents the disconnector from being pulled or closed under load, but also prevents illegal operations that violate the switch and switch operation principles. 3. Advantages of improved wiring
(1) This improved wiring not only retains the advantages of the original disconnector control wiring, but most importantly, it can effectively prevent illegal operations that violate the switch and switch operation principles and reduce unnecessary accidents.
(2) This improved wiring is simple, reliable, and requires less investment. It is suitable for wiring with electromagnetic locks to prevent errors and control wiring of disconnectors with pneumatic, electric, and electric hydraulic operations.
(3) In devices that do not use program locks to prevent errors, it is equivalent to the function of program locks.