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Isolator Switch Simple, Reliable
Oct 23, 2017

The isolating switch is a kind of switch device without arc extinguishing device, which is mainly used to disconnect the circuit without load current, isolate the power supply, and have obvious disconnect point in the state of the gate to ensure the safety of other electrical equipment. It can reliably pass the normal load current and short-circuit fault current in the closing state. Because it does not have a special arc extinguishing device, can not cut off the load current and short-circuit current. Therefore, the isolation switch can only be operated when the circuit breaker has been disconnected, and it is strictly prohibited to carry the load operation, so as to avoid serious equipment and personal accidents. Only the voltage transformer, arrester, excitation current does not exceed 2A no-load transformer, the current does not exceed 5A no-load line, can use the isolating switch to carry on the direct operation.

1. The improvement principle of isolating switch control circuit

In isolation switch control and locking loop, the auxiliary contact point is threaded into the isolating switch, that is, the side isolating switch in the bus side isolating switch is closed to the auxiliary contact point, and the line side isolating switch control loop is threaded into the bus side isolating switch often opens the auxiliary contact point.

2, the use of electromagnetic lock to prevent false isolation switch locking connection

(Take single bus feeder as an example) Figure 1 is the original control wiring. This kind of wiring can effectively prevent the load pull, the isolation switch, but may cause the isolation switch operation sequence reversal.

Power outage operation: After opening the circuit breaker, can only open the line side isolating knife gate, can open the bus side isolating knife gate.

Transmission operation: The circuit breaker in the disconnect position, can only be combined with the bus side isolation knife Gate, to close the line side isolation knife. This kind of wiring not only prevents the load pulling and isolating switch, but also prevents violating the operation principle of the switch and the knife gate.

3, improve the advantages of wiring

(1) This kind of improved wiring not only retains the advantages of the original isolating switch control wiring, but the most important is that it can effectively prevent the violation of the switch and the operation principle of the knife gate and reduce the unnecessary accidents.

(2) This kind of improved wiring is simple, reliable and less investment. Applicable to the use of electromagnetic lock and error-proof wiring and pneumatic operation, electric operation, Electric hydraulic operation of the isolation switch control wiring.

(3) In a device that does not use a program lock to prevent errors, it is equivalent to the function of a program lock.