摘要
随着电力系统的发展、配电事故的增多、电容电流的增大，有必要研究微机化、智能型的配电网电容电流测试系统。通过对各种电容电流测试方法的研究，提出了单相经电阻接地的测试方法并设计出了6～10kV配电网使用的微机型电容电流测试仪。该测试仪基于对称分量法的原理，通过测量电网单相经电阻接地时的二次零序电压UR02、流过接地电阻的电流IRE及电网单相直接接地时的二次零序电压即TV二次线电压U02，能够间接得到电网单相直接接地时的接地电流。根据所测的IR∑和UR02的相位关系，能够进一步得知电网的电容电流Ic∑和电网对地绝缘电阻电流IR∑的大小及中性点经消弧线圈接地电网中消弧线圈的补偿情况。通过现场实例测试证明，该测试仪具有操作较安全、简便易用、测量时间短、测量结果准确等优点。
Firstly, the paper introduces some different schemes to measure capacitive current and discusses their merits and demerits. Then the applied method which measures and calculates the capacitive current of distribution network with single phase to earth via resistance is put forward, and the novel microcomputer-based, intelligent measurement system of capacitive current which can be used in the 6-10 kV distribution network is designed. Based on the symmetrical component principle, the measurement system can indirectly acquire the single phase to earth current of the tested distribution network by the measurement of the UR02 IRE and U02. Here UR02 stands for the secondary zero sequence voltage of the distribution network when it has single phase to earth fault via resistance. IRE stands for the current through the earth resistance. U02 stands for the secondary zero sequence voltage of the distribution network when it has single phase to earth fault directly. Meanwhile U02 is equal to the secondary phase-to- phase voltage of the distribution network which can be got from the voltage transformer of the distribution network. Furthermore, the absolute capacitive current of the whole distribution network Ic∑ and the whole insulated resistance current of the distribution network IR∑ can be calculated by testing the phase difference of the two vectors IRE and UR02. For those distribution network whose neutral points are earthed via arc-suppression coil, the compensation status of the coils is also known. Finally, by giving a measuring example, the author testifies that the discussed measurement system is easier to operation, more accurate, faster and safer than others.
出处
《高电压技术》
EI
CAS
CSCD
北大核心
2007年第3期99-103,共5页
High Voltage Engineering
关键词
配电网
电容电流
微机
测试仪
对称分量法
单相接地
distribution network
capacitive current
microcomputer
measurement system
symmetrical component
single phase to earth
