The Difference Between Low Voltage Pole Mounted Circuit Breakers And Disconnectors

Lv Pole Mounted Circuit Breakers is the main power control equipment of the substation. It has arc extinguishing characteristics. When the system is operating normally, it can cut off and connect the no-load and load current of the line and various electrical equipment; when the system fails, it cooperates with the relay protection to quickly cut off the fault current to prevent the expansion of the accident scope.

The isolating switch has no arc extinguishing device. Although the regulations stipulate that it can be operated in situations where the load current is less than 5A, it is generally not allowed to operate with load; but the isolating switch has a simple structure, and its operating status can be seen at a glance from the appearance, and there is an obvious disconnection point during maintenance.

The circuit breaker is referred to as "switch" in use, and the isolating switch is referred to as "knife switch" in use. The two are often used together. The difference between the high-voltage circuit breaker and the isolating switch is as follows:
1. The high-voltage load switch can be disconnected with load and has a self-arc extinguishing function, but its breaking capacity is very small and limited.
2. The high-voltage isolating switch generally cannot be disconnected with load. There is no arc extinguishing cover in the structure. There are also high-voltage isolating switches that can disconnect loads, but the structure is different from the load switch and is relatively simple.
3. Both high-voltage load switches and high-voltage isolating switches can form obvious disconnection points. Most high-voltage circuit breakers do not have isolation functions, but a few high-voltage circuit breakers do.
4. High-voltage isolating switches do not have protection functions. The protection of high-voltage load switches is generally fuse protection, which only has quick break and overcurrent.
5. The breaking capacity of high-voltage circuit breakers can be made very high during the manufacturing process. It mainly relies on adding current transformers to cooperate with secondary equipment for protection. It can have short-circuit protection, overload protection, leakage protection and other functions.