光伏电站对送出输电线路选相元件的影响研究

通过某地区电网分析了光伏电站对送出输电线路相电流差突变量选相元件和序分量选相元件的影响。光伏电站的容量相对于系统容量很小,在送出主变中性点接地的系统中,当送出输电线路发生接地故障时,光伏电站侧零序等值阻抗远小于其正、负序等值阻抗,故障电流主要成分为零序电流,因而三相故障电流幅值、相位相近,致使选相元件误选相。以某地区光伏电站并网为例,在PSCAD/EMTDC中分别搭建了基于相电流差突变量和基于序分量的选相元件的仿真模型,并对两种选相元件进行测试。仿真结果表明两种选相元件的动作性能均受到严重影响。

Research of the photovoltaic plant influence on the outgoing transmission line phase selector

This paper studies the influence to phase selectors based on the phase current difference suddenly-change and the sequence component from photovoltaic plant by a regional power grid. The capacity of photovoltaic plant compared with the system capacity is very small, in the system with outgoing main transformer neutral grounding, when a ground fault occurs in outgoing transmission line, zero sequence impedance is far less than positive sequence and negative sequence impedance, the main component of the fault current is zero sequence current, so the magnitude and phase of the three-phase currents are similar, resulting in erroneous phase selection. Taking a regional grid-connected photovoltaic plant for example, phase selector models based on the phase current difference suddenly-change and the sequence component are built and tested in PSCAD / EMTDC, and simulation results show that the action performances of phase selectors are severely affected.