直流线路故障定位对过压抑制影响的机理分析

Effect Analysis of Fault Location on Overvoltage Suppression in DC Line

极间短路是直流微电网线路的常见故障。为抑制短路切断时的过电压,RD泄放支路并联法被广泛采纳,而LC故障定位电路正在被应用,对泄放支路的过压抑制功能产生明显影响。建立了RD泄放支路、LC定位支路和故障线路组成的并联系统的三阶线路模型,采用求解三阶线路模型的特征根的方法,明确了LC定位支路对RD泄放支路过压抑制的影响机理,解耦了参数变化对过压衰减的影响。在仿真中对该线路模型的效果进行了验证。

Line-to-line fault is common fault in DC micro-grid, RD energy release branch is used to suppress overvoltage when short cuicuit is cut off. LC probe branch is applied which influences overvoltage suppression greatly. So the parallel system including RD energy release branch, LC probe power branch and fault line was established, its operation process was expounded. By extracting the roots of third-order line model, the influence mechanism of LC probe branch on voltage suppression was explicated, decoupling the effect of parameter change on overvoltage attenuation. And it was verified in the simulation.