配电网单相接地故障选线方法的研究

Research on the Single-phase Earth-fault Selecting Method for the Distribution Network

随着用户侧非线性负荷的增加,系统正常运行时线路中的谐波分量增加,故障时难以精确识别故障线路的零序电流谐波分量,使得以往利用滤波器进行五次谐波分析法的精度降低。为了解决这个问题,将应用于风电并网发电的锁相环用于小电流接地系统故障选线,对故障信号进行处理,最后比较了各个出线波形的幅值以及相位,从而很好的确定了故障线路。以10kV架空线-电缆混合线路为例,建立锁相环的小信号模型,利用锁相环将波形中的五次谐波进行锁定。最后用Simulink进行了仿真,检验了该方法的可行性。

With the increase of non-linear loads in the user side,the harmonic component of current when the system is in normal operation has increased,it is difficult to identify the fault line by the harmonic components accurately,so the precision of fifth harmonic analysis method using filters is decreased.In order to solve this problem,the phase-locked loop used in wind power integration was applied for fault line selection in small current grounding system,by processing fault signal and comparing different lines wave phase and amplitude to select the fault line,it obtained the very good effect.To 10kV power cable with transmission mixed lines for example,establish the small signal model of phase locked loop to lock the fifth harmonic waveform.And use Simulink to verify,the results prove the correctness of the analysis.