基于小波阈值去噪和CEEMD的混合三端直流输电线路故障测距

Considering the influence of wave speed, precision of traveling wave head calibration and noise on the location accuracy of the traveling wave method, a hybrid three-terminal HVDC transmission line location method based on wavelet threshold denoising and CEEMD-HT is proposed. First, the fault signal is denoised by wavelet threshold denoising, and then the arrival time of the initial wave head is calibrated by combining complementary ensemble empirical mode decomposition and a Hilbert transform (CEEMD-HT). Then the fault branch is identified according to the ratio of the time of the fault traveling wave to the measuring end. Finally, considering that the traveling wave velocity is difficult to determine accurately, based on the known line length and the initial arrival time of the wave head, a new location method independent of the wave velocity is proposed. The simulation results show that the proposed method can calibrate the wave head effectively, and the location results are not affected by wave velocity, fault distance, fault type, transition resistance and noise. The error of this method is smaller than the double end method, and the HHT and wavelet packet ranging algorithm.