ELECTROMAGNETIC INTERFERENCE ANALYSIS IN 500 KV SUBSTATION

Transient electromagnetic interference (EMI) generated during the switching of dis-connector and circuit breakers in 500 kV substations may cause malfunction or damage to electronic equipment positioned nearby if appropriate immunity measures are not taken. After analyzing the results and waveform characteristics of EMI, the experimental result shows that the EMI in secondary circuit is mainly caused by switch and breaker operations, their waveform characteristic is damped oscillatory, and the intensity of wave should not be neglected. The results also show that the EMI due to switch operations is caused by the electric discharge in primary circuit, and the EMI due to breaker operations is caused by the inductor, contactor oscillate and electric discharge. The impact of the electric discharge of the breakers in primary circuit into the secondary circuit is negligible.