电网经过渡电阻短路时电流电压的分析与仿真.docVIP

\ 电网经过渡电阻短路时电流、电压 的分析与仿真 东南大学成贤学院毕业设计报告（论文） 诚 信 承 诺 本人承诺所呈交的毕业设计报告（论文）及取得的成果是在导师指导下完成，引用他人成果的部分均已列出参考文献。如论文涉及任何知识产权纠纷，本人将承担一切责任。 学生签名： 日　　期： 电网经过渡电阻短路的模拟与仿真 摘 要 短路是电力系统中危害最严重的故障，而现实中短路点往往都存在过渡电阻，为了保证继电保护装置的可靠正常工作，本文重点分析了电网经过渡电阻各种短路时的电气量变化特点，分别讨论了相间短路与接地故障时，电流、电压的变化规律与过渡电阻的关系。理论分析表明：电流、电压随过渡电阻由零到无穷大的变化轨迹均为半圆。相间短路时，两故障相电流大小相等、方向相反，数值随过渡电阻的增大而减小；故障相电压变化情况较为复杂，而非故障相电压变化规律不仅与过渡电阻有关还与故障点等值阻抗有关。其他两种经过渡电阻接地短路时的电流、电压变化规律与之变化情况虽不同但类似。最后利用PSCAD进行了仿真验证，仿真结果与理论分析相符。 关键词：短路；模拟仿真；过渡电阻；电流电压变化规律；电力系统计算机辅助设计 Simulation of Power System Short Circuit Through Fault Impedance Abstract Short circuit is the most far-reaching fault in power system.While there are fault impedance at the fault point.To ensure the reliable operation of protective relaying,this paper is aiming at putting emphasis on the analysis of the changing rule of current and voltage when power system occurs short circuit through fault impedance.This paper discussed the relationship between voltage and current changing rule with fault impedance when line to line short circuit and line to ground fault take place in power system.Theoretical analyzes that the track of current and voltage change with the fault impedance ranges from zero to infinity are both half a circuit.The current of fault phase of the line to line short circuit are of the same magnitude but in the opposite direction.The magnitude of each current decreases with the increase of the fault impedance .While the voltage rule of the phase in fault is quite complex and the voltage not in fault changes not only with fault impedance but also with the equal impedance of the fault point.The current and voltage of the two kinds of short circuit are not totally the same but similar to each other.Finally PSCAD analogs the rule of current and voltage . Keywords:Short circuit;fault impedance;change rule;PSCAD 目 录 摘 要 I Abstract II 目 录 III 第一章 引言 1