1. It is used to isolate the power supply and disconnect the high-voltage maintenance equipment from the live equipment so that there is an obvious disconnection point between them.
2. The isolating switch cooperates with the circuit breaker, and the switching operation is performed according to the needs of the system operation mode to change the system operation wiring mode.
3. Used to connect or disconnect small current circuits.
Generally, a set of isolation switches are installed on the front and rear sides of the circuit breaker. The purpose is to isolate the circuit breaker from the power supply to form an obvious disconnection point; because the original circuit breaker uses an oil circuit breaker, the oil circuit breaker needs frequent maintenance. Therefore, there must be obvious disconnect points on the two sides to facilitate maintenance; under normal circumstances, the outlet cabinet is powered down from the upper bus through the switch cabinet, and a set of isolation switches is required in front of the circuit breaker to isolate from the power supply, but sometimes, There is also the possibility of incoming calls behind the circuit breaker, such as through other loops, capacitors and other devices, so a set of isolating switches is also needed behind the circuit breaker.
The isolation switch is mainly used to reliably isolate the parts that need to be powered off and the live parts in the high-voltage power distribution device to ensure the safety of maintenance work. The contacts of the isolating switch are all exposed to the air and have an obvious disconnection point. The isolating switch has no arc extinguishing device, so it cannot be used to cut off load current or short-circuit current. Otherwise, under the action of high voltage, the disconnection point will produce a strong arc , And it is difficult to extinguish by itself, and may even cause arcing, burn equipment, and endanger personal safety. This is a serious accident called "pull disconnecting switch with load". The isolation switch can also be used to switch some circuits to change the operating mode of the system. For example: In a double-bus circuit, an isolating switch can be used to switch the circuit in operation from one bus to another. At the same time, it can also be used to operate some small current circuits.