Isolating switch is a kind of switching device mainly used for "isolating power supply, switching operation, to connect and cut off small current circuits", without arc extinguishing function. When the isolating switch is in the open position, there is an insulation distance between the contacts that meets the specified requirements and an obvious disconnection mark; when in the closed position, it can carry current under normal loop conditions and abnormal conditions (such as short circuits) within a specified time Electric current switching device. It is generally used as a high-voltage isolating switch, that is, an isolating switch with a rated voltage above 1kV. Its working principle and structure are relatively simple, but due to the large amount of use and high reliability requirements, it is necessary for the design, establishment and construction of substations and power plants. The impact of safe operation is greater. The main feature of the isolating switch is that it has no arc extinguishing capability and can only open and close the circuit when there is no load current.
1. During the overhaul of electrical equipment, provide an electrical interval and a clearly visible disconnection point to protect the personal safety of maintenance personnel.
2. Isolating switch cannot be operated with load: it cannot be operated with rated load or large load, load current and short-circuit current cannot be divided or combined, but those with arc extinguishing chamber can be operated with small load and no-load circuit.
3. In general power transmission operation: first close the isolating switch, then close the circuit breaker or load switch; in the case of power off operation: first disconnect the circuit breaker or load switch, and then disconnect the isolating switch.
4. The selection is the same as other electrical equipment, and its rated voltage, rated current, dynamic stable current, thermal stable current, etc. must meet the needs of the use occasion.
The function of the isolating switch is to disconnect the circuit with no load current. The equipment under inspection and the power supply have an obvious disconnection point to ensure the safety of the maintenance personnel. The isolating switch cannot cut off the load current and short-circuit current without a special arc extinguishing device. Therefore, the isolating switch can only be operated when the circuit breaker opens the circuit.