小电阻接地方式存在的死区问题分析及试验研究  

Analysis and Experimental Study on the Dead Zone Problem of Small Resistance Grounding Mode

作　　者：李悦 洪书文 潘子仁 毛兴华 LI Yue;HONG Shuwen;PAN Ziren;MAO Xinghua(School of Electrical and Information Engineering,Changsha University of Science and Technology,Changsha 410114,China)

机构地区：[1]长沙理工大学电气与信息工程学院,长沙410114

出　　处：《电瓷避雷器》2020年第2期131-136,共6页Insulators and Surge Arresters

摘　　要：针对小电阻接地方式在配电网实际运行中暴露出来的安全问题和技术问题,重点分析了小电阻接地中架空绝缘导线断线接地带来的安全风险问题和绝缘子闪络带来的供电可靠性问题,在国网配电网智能化应用及关键设备联合实验室漯河真型试验场做了小电阻接地方式对配电网单相接地故障处理试验,并用计算机仿真软件MATLAB仿真了不同接地过渡电阻下故障零序电流的大小,试验和仿真结果表明:小电阻接地方式在发生绝缘导线断线接地时,由于接地过渡电阻较大,系统零序保护会失灵,无法立即切除带电线路,给过往行人带来安全风险;当绝缘子闪络时,因杆塔有接地装置,接地过渡电阻很低,属于金属性接地故障,故障电流较大,线路会立即跳闸,频繁跳闸使供电可靠性下降。In view of the safety and technical problems that the small resistance grounding method exposed during the actual operation of the distribution network,the safety risks caused by the broken earthing of overhead insulated conductors in small resistance grounding and the power supply reliability in case of the insulator flashover are analyzed.In terms of reliability,a small-resistance grounding method was used to test the single-phase grounding fault of the distribution network at the intelligent power distribution network application and key equipment joint laboratory-Luohe Real Testing Site,and the computer simulation software MATLAB was adopted to simulate different grounding.The magnitude of the fault zero-sequence current under the transition resistance,experimental and simulation results show that:when the insulated wire is disconnected and grounded in a small-resistance grounding mode,due to the large grounding transition resistance,the system zero-sequence protection will fail and the live line cannot be immediately cut off,causing potential safety hazard to pedestrians.When the insulator flashes,the tower has a grounding device,and the grounding transition resistance is very low.It belongs to a metallic ground fault.If the fault current is large,the line will trip immediately,which will negatively affects the reliability of the power supply.

关 键 词：小电阻接地 人身安全 断线高阻接地 供电可靠性 

分 类 号：TM862[电气工程—高电压与绝缘技术]