What is the difference between earth leakage relay and earth leakage circuit breaker
A) earth leakage relay
Has the following basic functions:
1. Regardless of the combined leakage current of the power supply line, whether it is a slow variable or a sudden change, when it continues to reach the rated operating value IΔn, the leakage leakage relay trips. When it is detected at time t3 after a delay, it should be tripped again and kept locked to achieve True one-time auto-reclosing. At this time, the setting of the rated leakage action value can be based on the leakage of power supply lines in various places and the sensitivity of 2 to 3 gears in the dry and rainy seasons, such as 75mA, 150mA, 300mA, etc., which can be adjusted by the user. The reclose delay time is about 30s. , Taking into account the stable and reliable operation and leakage protection.
2. When the leakage current of the power supply line reaches the rated operating value IΔn, the leakage protector trips, and the leakage current is smaller than the rated value or even disappears within the delay time. The leakage protector should be able to automatically reclose and maintain normal operation. This can ensure effective operation. It can also avoid interference and improve the continuity and stability of power supply.
3． The operating time of the leakage current leakage relay should be appropriately lengthened. This machine uses 0.2s, and the combined device consisting of AC contactors should be around 0.3s. This can avoid the instantaneous start-stop interference of power supply lines, while taking into account the protection of classification and the leakage at the home With the cooperation of the relay, it does not trip. Users can choose the same manufacturer's products, and require the manufacturers to do a good job of hierarchical protection and coordination when they leave the factory, which can solve the worries during operation.
B) Leakage circuit breaker
The leakage protection part is composed of a zero-sequence current transformer (sensing part), an operation controller (control part) and an electromagnetic release (action, execution part).
For all phases of the protected main circuit, the zero line passes through the core of the zero-sequence current transformer to form the primary side of the zero-sequence current transformer.