基于故障时域电流波形相似度的UPFC线路纵联保护

UPFC Line Pilot Protection Based on Fault Transient Current Waveform Similarity

当统一潮流控制器(UPFC)检测到线路发生故障时,为避免其内部电力电子设备损坏,有必要快速导通晶闸管旁路开关(TBS)以旁路串联侧换流器,由于UPFC的结构发生改变,此时线路中的电气量也随之改变,从而导致原有保护难以适应当前状态。通过对比分析UPFC线路区内、外发生故障时,线路两端短路电流波形特征的变化规律,提出一种基于故障时域电流波形相似度的UPFC线路纵联保护方案。经仿真验证,所提保护方案可以迅速、精准地识别在不同故障位置、故障类型、潮流水平下的故障,且不受TBS导通影响,具有一定的抗过渡电阻能力。

When the UPFC detects a line fault,it is necessary to quickly turn on the TBS to bypass the series side converter in order to avoid the damage of its internal power electronic equipment.Due to the change of UPFC structure,the electrical quantity in the line also changes,which makes the original protection difficult to adapt to the current state.By comparing and analyzing the waveform characteristics of shortcircuit current at both ends of the line when faults occur inside and outside the UPFC line area,a pilot protection scheme for UPFC line based on the waveform similarity of fault time domain current is proposed.The simulation results show that the proposed protection scheme can rapidly and precisely identify the faults in different fault locations,fault types and power flow levels,and is not affected by the TBS conduction,and has a certain ability to resist the transition resistance.