小电阻接地系统单相断线故障电压特征分析  

Analysis of Voltage for Single-phase Break Fault Voltage in Low-resistance Grounding System

作　　者：张灿军 陈梦琦 张宗熙 薛永端[2] 金鑫[2] ZHANG Canjun;CHEN Mengqi;ZHANG Zongxi;XUE Yongduan;JIN Xin(Zhongshan Power Supply Bureau of Guangdong Power Grid Co.,Ltd.,Zhongshan 528400,China;College of New Energy,China University of Petroleum(East China),Qingdao 266580,China)

机构地区：[1]广东电网有限责任公司中山供电局东区供电分局,广东中山528400 [2]中国石油大学(华东)新能源学院,山东青岛266580

出　　处：《供用电》2019年第11期64-70,共7页Distribution & Utilization

基　　金：国家自然科学基金项目（51477184）;广东电网有限责任公司科技项目（032000KK52180064）~~

摘　　要：小电阻接地配电网发生单相断线(含坠地)故障时,由于过渡电阻大、故障电流小,现有零序过电流保护将拒动。针对小电阻接地配电网分别发生断线不接地、断线并电源侧接地及断线并负荷侧接地3种类型故障,分析断口前后零序电压和线电压特征,发现:断口前后零序电压主要与断线类型、接地点过渡电阻和下游负荷阻抗有关;在3种断线情况下,断口后的零序电压幅值总明显大于断口前的零序电压;断口后故障相分别与2个健全相之间的线电压幅值之和总是等于或者大于正常线电压的幅值,而且明显小于2倍的健全线电压幅值;上述特征在接地电阻为无穷大时依然适用,可用以实现小电阻接地配电网单相断线故障定位。利用Matlab搭建典型配电网模型进行大量仿真,验证了分析结果的正确性。When single-phase break fault(including grounding fault) occurs in the distribution network with low-resistance grounding system,due to the large transition resistance and small fault current,the existing zero sequence current protection will be rejected. In this paper,zero sequence voltage and line voltage characteristics before and after fracture are analyzed for three types of faults in the distribution network with low-resistance grounding,namely ungrounded line breakage,line breakage with grounding at the power supply side,and line breakage with grounding at the load side,it is found that the zero sequence voltage before and after the break is mainly related to the type of break fault,the transition resistance at the junction and the downstream load impedance. Under the three conditions of wire breakage,the amplitude of zero sequence voltage after the fracture is obviously greater than the zero sequence voltage before the fracture;After the fracture,the sum of the line voltage amplitudes between the fault phase and the two healthy phases is always equal to or greater than the normal line voltage amplitude,but it is obviously less than twice the healthy line voltage amplitude. The above characteristics are still applicable even when grounding resistance is infinite,and can be used to locate the fault of single-phase disconnection of low-resistance grounding distribution network. Matlab is used to build a typical distribution network model for a lot of simulations,which verifies the correctness of the analysis results.

关 键 词：小电阻接地系统 断线接地 故障分析 零序电压 线电压 

分 类 号：TM77[电气工程—电力系统及自动化]