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

针对行波法测距精度受波速、行波波头标定的精度以及噪声的影响,提出一种基于小波阈值去噪和CEEMD-HT结合的混合三端直流输电线路测距方法.首先利用小波阈值去噪对故障信号滤噪,然后对滤噪后的信号使用互补集合经验模态分解和希尔伯特变换标定初始波头的到达时间.再根据故障行波到达测量端时间比值识别故障支路.最后考虑到行波波速难...

Fault location of hybrid three-terminal HVDC transmission lines based on wavelet threshold denoising and CEEMD

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. This work is supported by the General Project of National Natural Science Foundation of China (No. 51777166).