Research on Transient Protection of HVDC Transmission Line Based on Wavelet Energy

The DC line fault signal contains rich transient information. Aiming at the problems of poor reliability and insufficient sensitivity of single-ended protection of traditional DC transmission lines, a protection principle that uses only transient currents to achieve full-line rapid operation of DC transmission lines is proposed. The influence of the HVDC transmission line and the constructed boundary model on the fault transient signal is analyzed, and the multi-resolution wavelet is used to analyze the fault current signal and obtain the corresponding wavelet energy. The bipolar DC transmission system model based on the CIGRE model was built on PSCAD and simulated. The results show that the method can accurately determine the fault within and outside the fault zone, and is not affected by the transition resistance and line length, and has high accuracy.