[Types and Principles of Rejection Action of Leakage Circuit Breakers]: 1. In TN-C-S system, if the detection circuit is between the PEN line of TN-C section and the L line, the leakage circuit breaker will refuse to operate on the PE line of TN-S section; 2. In TN-S system, because the circuit installer connects the N line to the switch, if the N line is broken..
1. In the TN-C-S system, if the detection circuit is between the PEN line and the L line in the TN-C section, the leakage circuit breaker will refuse to operate on the PE line in the TN-S section.
2. In TN-S system, because the circuit installer connects the N-line to the switch, if the N-line is broken, the leakage signal will not be detected in the L-line when the leakage occurs, and the leakage circuit breaker will refuse to act.
3. In the TN-C-S system, the leakage circuit breaker will refuse to act because the circuit installer connects the N-line with the PE-line.
4. When installing and using, because the sensitivity of leakage circuit breaker is too low, the actual leakage value is not up to the prescribed value, it will refuse to operate.
The main reasons for the misoperation of leakage circuit breakers are as follows:
1. In TN-C-S system, the wrong action will be caused because the circuit installer connects the PE and N wires inversely.
2. In the three-phase four-wire circuit of lighting and power combination, the three-pole leakage circuit breaker is chosen incorrectly, and the zero line of the load directly causes the wrong action on the power side of the protector.
3. There are high-power electrical appliances near the leakage protector. When the electrical appliances are switched on and off, electromagnetic interference will cause misoperation.
4. The insulation resistance of phase line and zero line is too low, part of the current leaks out of the earth through the leakage place, which causes the wrong action when the circuit is normal through the current vector of zero sequence current transformer and is not zero.
5. When the PE line of the electric equipment shell is connected with the working neutral line, it causes the wrong action.
6. The three-phase power supply wire passing through the three-phase leakage protector fails to pass through the zero-sequence transformer in the same direction, resulting in misoperation.
7. When installing and using, the leakage circuit breaker will misoperate because of its high sensitivity selection.
