基于小波时间熵的MMC-HVDC架空线路单极接地故障检测方法  

Wavelet Entropy Based Single Pole Grounding Fault Detection Approach for MMC-HVDC Overhead Lines

作　　者：王帅 毕天姝 贾科 

机构地区：[1]新能源电力系统国家重点实验室(华北电力大学),北京市昌平区102206

出　　处：《电网技术》2016年第7期2179-2185,共7页Power System Technology

基　　金：国家重点基础研究发展计划(973计划)(2012CB215206);高等学校学科创新引智计划资助(B08013)~~

摘　　要：直流线路保护问题是模块化多电平柔性直流输电(modular multilevel converter high voltage direct current,MMC-HVD)采用架空线路输电亟需解决的关键技术难题之一。针对这一问题,首先,通过分析MMC-HVDC系统结构和线路行波过程,指出MMC-HVDC单极接地故障电流的特征主要体现在暂态量的变化上;其次,进一步提出利用小波时间熵的方法实现快速准确故障检测,分析对比了接地故障、雷击和噪声等条件下不同频带信号分量的小波时间熵分布特征,给出了可靠区别故障和雷击、噪声的判据。仿真结果表明:所提方法能够准确检测MMC-HVDC架空线路的单极接地故障,并可靠排除交流区故障、雷击和噪声的干扰。DC line protection is a key technical problem to solve in overhead line transmission technology with modular multilevel converter HVDC（MMC-HVDC）. In this paper, fault current characteristics for MMC-HVDC single pole grounding fault were analyzed by reviewing MMC-HVDC converter structure and travelling wave propagation process. It pointed out that fault characteristics were mainly reflected in change of transient component. Then a novel fault detection approach using wavelet time entropy was proposed, because wavelet time entropy had time-frequency localization traits and ability to characterize transient signal status. Time entropy distribution in different frequency bands of lightning, noise and fault signals was analyzed and compared. Fault detection criterion for differentiating fault from lightning and noise signals was suggested. Computer simulations were carried out. The results show that the proposed approach can detect pole to ground fault and eliminate interference signals such as AC side fault, lightning and noise signals.

关 键 词：柔性直流 架空线路 故障检测 小波时间熵 雷击干扰 

分 类 号：TM72[电气工程—电力系统及自动化]