In order to prevent the leakage problem, in addition to the grounding of the charging pile, the selection of the leakage protector is also very important. According to the national standard GB/T 187487.1, the leakage protector of the charging pile should use type B or type A, which not only protects against AC leakage, but also protects against pulsating DC. The biggest difference between Type B and Type A is that Type B has added protection against DC leakage. However, due to the difficulty and cost constraints of type B detection, most manufacturers currently choose type A. The biggest harm of DC leakage is not the personal injury, but the hidden danger caused by the failure of the original leakage protection device. It can be said that the current leakage protection of charging piles has hidden dangers at the standard level.
Type A leakage circuit breaker
The A-type leakage circuit breaker and the AC-type leakage circuit breaker are basically the same in terms of working principle (the leakage value is measured through the zero-sequence current transformer), but the magnetic characteristics of the transformer are improved. It ensures tripping under the following conditions:
(a) Same as AC type.
(b) Residual pulsating DC current.
(c) A smooth DC current of 0.006A is superimposed on the residual pulsating DC current.
Type B leakage circuit breaker —— (CHINAEVSE can do RCD Type B)
Type B leakage circuit breakers can reliably protect sinusoidal AC signals, pulsating DC signals and smooth signals, and have higher design requirements than type A leakage circuit breakers. It ensures tripping under the following conditions:
a) Same as Type A.
b) Residual sinusoidal alternating current to 1000 Hz.
c) The residual AC current is superimposed with a smooth DC current of 0.4 times the rated residual current
d) The residual pulsating DC current is superimposed with 0.4 times the rated residual current or a smooth DC current of 10mA (whichever is greater).
e) Residual DC currents generated by the following rectification circuits:
- two half-wave bridge connections line to line for 2-, 3- and 4-pole earth leakage circuit breakers.
- For 3-pole and 4-pole earth leakage circuit breakers, 3 half-wave star connections or 6 half-wave bridge connections.
Post time: Jun-19-2023