小电阻接地系统高阻接地故障纵联差动保护  

Longitudinal Differential Protection of High Resistance Grounding Faults in Low-resistance Grounding System

作　　者：任伟[1] 薛永端[1] 徐丙垠[2] 李钰琪 REN Wei;XUE Yongduan;XU Bingyin;LI Yuqi(College of New Energy,China University of Petroleum(East China),Qingdao 266580,Shandong Province,China;Smart Grid Research Institute(Shandong University of Technology),Zibo 255049,Shandong Province,China)

机构地区：[1]中国石油大学(华东)新能源学院,山东省青岛市266580 [2]智能电网研究院(山东理工大学),山东省淄博市255049

出　　处：《电网技术》2021年第8期3276-3282,共7页Power System Technology

基　　金：国家自然科学基金项目(52077221)。

摘　　要：为提高故障处理速度与供电可靠性,国内部分小电阻接地配电网已试点采用纵联差动保护技术处理接地故障,但其零序过电流保护策略不能有效处理高阻接地。分析计及线路阻抗时的小电阻接地系统单相接地故障特征,利用零序电压与零序电流间的比例关系,提出一种零序电压幅值修正的接地故障差动保护方案。该方案利用零序电压信息自适应修正两终端间电流差,同时针对极端条件下区段数量较少、零序压降稍大等限制因素,适当提高整定值以避免故障点上游保护误动。经仿真与人工接地试验数据验证,该方案可将纵联差动保护耐电阻能力提高至1000W以上。In order to improve the speed of fault handling and the power supply reliability,some domestic low-resistance grounding distribution networks have piloted to use the longitudinal differential protection technology to deal with the grounding faults.However,the zero sequence overcurrent protection strategy can not deal with high resistance grounding faults effectively.This paper analyzes the characteristics of single phase grounding faults in the low-resistance grounding system considering the line impedance.By using the proportional relationship between zero sequence voltage and zero sequence current,it then proposes a longitudinal differential protection scheme for grounding faults with amended zero sequence voltage amplitude.In this scheme,the zero sequence voltage information is used to adaptively correct the current between the two terminals.Meanwhile,considering the limiting factors,for example,there are fewer terminals or the zero sequence voltage drops greatly under extreme conditions,the setting value will be increased to avoid the upstream terminals mal-operation.It is verified by simulation and experiment data that the longitudinal differential protection is able to deal with more than 1000Ωgrounding faults.

关 键 词：小电阻接地系统 高阻接地故障 零序电压 零序电流 差动保护 

分 类 号：TM721[电气工程—电力系统及自动化]