利用行波波形改进编辑距离的柔性直流输电线路后备保护方案  

Backup Protection Scheme for Flexible DC Transmission Line by Traveling Wave Waveform Similarity Based on Improved Editing Distance

作　　者：童晓阳[1] 权文杰 李智 席俊烨 董星星 TONG Xiaoyang;QUAN Wenjie;LI Zhi;XI Junye;DONG Xingxing(School of Electrical Engineering,Southwest Jiaotong University,Chengdu 611756,Sichuan Province,China)

机构地区：[1]西南交通大学电气工程学院,四川省成都市611756

出　　处：《电网技术》2023年第1期294-300,共7页Power System Technology

摘　　要：针对行波主保护在低信噪比、高过渡电阻情况下保护方案失效的问题,该文提出一种利用小波阈值降噪和改进编辑距离算法的直流输电线路后备保护方案。根据噪声信号与故障信号小波系数差异较大的特性,采用小波降噪方法对故障行波信号进行降噪预处理。区外故障时线路两侧行波波形相似度较高,区内故障时相似度较低。根据此特性,提出一种改进的编辑距离算法,克服数据不同步和异常值的影响,实现线路两侧故障行波波形相似度的精确计算,建立故障识别判据。仿真实验结果表明,该算法能够准确地识别区内外故障,相较于原始的编辑距离算法和不同双端保护方案,具有更强的抗噪声干扰和耐受过渡电阻能力。Aiming at the failure of the protection scheme of traveling wave main protection under the condition of low signal-to-noise ratio and high transition resistance, a backup protection scheme of DC transmission line based on wavelet threshold denoising and improved editing distance algorithm is proposed in this paper. According to the characteristics of large difference in wavelet coefficients between noise signal and fault signal, wavelet denoising method is used to denoise the fault traveling wave signal. The similarity of traveling wave shape on both sides of the line is high in case of external fault,and low in case of internal fault. According to this characteristic, an improved edit distance algorithm is proposed to overcome the influence of data synchronization and outliers,realize the accurate calculation of fault traveling wave similarity on both sides of the line, and establish the fault criterion inside and outside the flexible DC transmission line.The simulation results show that the algorithm can accurately identify the faults inside and outside the area. Compared with the original editing distance algorithm and other two terminal protection schemes, it has stronger anti-noise interference and resistance to transition resistance.

关 键 词：柔性直流输电 行波 小波降噪 编辑距离 相似度 

分 类 号：TM721[电气工程—电力系统及自动化]