利用电流突变特性的高压直流输电线路纵联保护新原理

A New Pilot Protection Principle for HVDC Transmission Lines Based on Current Fault Component

通过对直流输电线路区内、区外故障电流特征的分析可知:直流线路内部发生故障后的暂态过程中,线路两端电流突变方向相同;而线路外部故障后的暂态过程中,线路两端电流突变方向相反。根据该特征,提出了一种新的直流输电线路纵联保护原理,它仅利用线路两端电流的突变,就可以有效地识别出区内、区外故障。文中还构造了电流突变的识别判据,并给出了其整定原则。仿真结果表明,在各种工况下该保护都能够灵敏、可靠地区分区内、区外故障。

For high voltage direct current（HVDC） transmission lines,the transient fault characteristics are that,if the fault point is in the line,the currents measured at both convert stations will be increased,and with the same changing trends;if the fault point is out of the line,the current measured at one convert station is increased,and the current measured at the other convert station is decreased,and with the opposite changing trends.According to such characteristics,and using the currents measured at both convert stations,a new pilot protection principle for HVDC transmission lines based on current fault component is proposed.This principle has no limitation on the sampling frequency.Internal and external faults of the line can be effectively identified only using the current fault component at both convert stations.On the other hand,the setting principle of the current fault component is given.The simulation results show that the method proposed can identify the fault reliably and rapidly in different conditions.