注入半波直流的小电流接地故障选线定位方法  

A method of fault line selection and fault point location with half-wave DC injection in distribution network

作　　者：高志鹏 张慧芬[2] 孙旭娜[2] 

机构地区：[1]胜利油田分公司临盘采油厂,山东临盘251507 [2]济南大学自动化与电气工程学院,山东济南250022

出　　处：《电力系统保护与控制》2013年第13期139-145,共7页Power System Protection and Control

基　　金：山东省自然科学基金(ZR2012EEL19);胜利油田分公司重点科技攻关项目(YC0808)~~

摘　　要：小电流接地故障选线定位问题是一直没有得到彻底解决的技术难题,判据特征量小是制约该问题的瓶颈。以增大判据特征量为思路,根据故障时配电网中性点对地电压的变化规律,提出从接地变压器一次侧中性点向故障系统注入较大的半波直流电流作为判据。详细分析了注入半波直流选线定位原理及其抗过渡电阻能力。经分析,注入的半波直流电流不影响配电网的正常运行,以满足半波直流电流的检测精度为条件确定注入电流的大小,中性点不接地和消弧线圈接地系统均适用且具有较高的抗过渡电阻能力。基于该原理的选线定位装置已投入现场试运行两年多,选线准确。The problem of fault line selection and location in non-effective earthed power system has not been perfectly solved because of small value of characteristic of criterion. Concerning enlarging the value of characteristic of criterion, a larger half-wave DC is injected to the fault distribution system through the primary neutral point of earthing transformer, based on the character of neutral voltage changes during pre-fault and post-fault period. The injected half-wave DC is used as the criterion. The principle of half-wave DC injection and its critical fault resistance are analyzed in detail. The analysis result shows the injected half-wave DC will not change the operation of distribution network and the value of injected half-wave DC can be calculated depending on the desired detecting accuracy of half-wave DC. It also shows that the half-wave DC injection method has a high tolerant capacity towards fault resistance both in isolated neutral system and resonant grounded system. Such equipment has been implemented for more than two years in power networks, and the result of detecting fault line is correct.

关 键 词：小电流接地系统 单相接地故障 选线定位 半波直流电流 注入法 

分 类 号：TM862[电气工程—高电压与绝缘技术]