光伏电源接入配电网的方向元件新判据
New Criterion of Directional Component in Distribution System with Photovoltaic Generator

光伏电源的控制策略不同于传统电源，传统方向元件不能正确判断故障方向，可能导致保护装置错误动 作．为此，研究了光伏电源在并网控制策略下的故障输出特性，以及光伏电源接入影响下的系统侧电源故障输出特 性，得到了配电网发生故障时光伏电源及系统电源输出故障电流的相位特征，以此为基础提出了一种基于正序故障 电流和故障前电压相位信息的方向元件新判据，并与传统方向元件进行了比较，得出了光伏电源接入的配电网中方 向元件的特性及整定计算方法．结果表明该方向元件判据在配电网不同故障条件下均能保证正确动作，同时避免了 传统方向元件易受电压死区及过渡电阻影响的问题．
Control strategy of photovoltaic(PV)generator is different from traditional generators．Conventional direc- tional component cannot judge the fault direction correctly in distribution system with PV generator，due to the spe- cial fault characteristic of PV generator．Thus fault characteristic of PV generator under grid-connected control strat- egy was investigated as well as the fault characteristic of the grid side generator．Phase characteristics of PV generator and grid side generator fault current were revealed．A new directional component criterion based on the phase informa- tion of positive-sequence current and pre-fault voltage was proposed based on this．It was compared with the tradi- tional directional component，and features and setting methods of the directional component in distribution system with PV generator were obtained．This criterion guarantees the reliability of the directional component in various fault situations of distribution system．Besides，it avoids the dead zone and transition resistance problem of traditional di- rectional component