Improvement for Phase Comparison Protection based on Wavelet Transform on Series Capacitors Compensated Lines

Z.-j. Liang, R. Wen, and J.-c. Tan (PRC)


Series capacitor, MOV, phase comparison protection, complex wavelet transform, and RTDS


When fault occurred near capacitor on the series capacitor compensated transmission line, the phase difference between the currents measured respectively at two ends of the transmission line may reach 180 degrees, which will result in the conventional phase comparison protection blocked. So an improved approach is proposed in which the wavelet transform is applied to extracted transient signals from fault currents, and the phase difference of transient component will be utilized in the improved protection schemes for fault locating. In the meantime the impact of MOV failure is also taken into account. Simulation results show that the improved algorithm can locate the fault position quickly and accurately, and is not affected by compensation degree or the position where the series compensated capacitor is installed, thus this improved algorithm is available for common transmission lines.

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