特高压多串补系统不同故障类型下电压特性分析

Analysis on Voltage Characteristics of Different Fault Types in Ultra High Voltage Transmission Line With Multi Series Compensation Capacitors

通过理论分析得到特高压多串补系统在不同故障类型及不同位置发生故障下的电压反向条件。针对我国"晋东南—南阳—荆门"特高压实际工程,建立含多端串补模型,推导出不同位置下的不同类型短路故障,尤其是单相接地故障时的解析表达式;然后,系统分析正向故障和反向故障时的电压特性,得出在多串补线路中,故障点位于线路不同位置将造成母线侧PT和线路侧PT相继发生电压反向,为分析特高压系统继电保护动作行为提供了依据;最后,文章利用PSCAD搭建特高压输电线路模型并进行仿真验证,仿真结果与理论分析一致。

The conditions of voltage reversal in UHV transmission line with multi series compensation capacitors under different fault types and at different locations are theoretically analyzed. Based on ＂Jindongnan-Nanyang-Jingmen＂ UHV actual project, a multi series compensation system model is established. And then, the analysis expression of voltage when different types of short-circuit fault occur, especially when single-phase ground fault occurs at different places, is deduced. This paper analyses systematically the voltage characteristics when forward fault and reverse fault occur, which comes to the conclusion that when fault point is located at different location of the transmission line with multi series compensation capacitors, bus-bar side PT and line side PT will have voltage reversal successively. It provides basis for analyzing protective relaying of UHV system. Finally, the model of UHV transmission line with multi series compensation capacitors based on PSCAD is established and simulated and the simulation results conform to that of theoretical analysis.