基于正序电流故障分量的输电线路故障检测

高压输电系统中传统后备保护定值整定困难，灵敏度易受到高阻接地、潮流转移等影响。文中提出了一种基于正序电流故障分量的输电线路故障检测算法。采用线路两端正序电流故障分量的矢量和幅值与矢量差幅值的比值作为线路的故障判断量，给出严格的公式推导，建立了故障检测的判据。理论分析了线路的故障判断量的分布特性，与本线路阻抗、两端背侧的系统等效阻抗、故障点位置的关系，证明了其与过渡电阻无关。在系统发生振荡时，将求解的故障定位值作为辅助判据。IEEE 39节点系统仿真实验表明，各类故障发生时所提算法均能够正确检测故障线路且不受故障位置、过渡电阻等影响，在非全相运行、负荷潮流转移时也能检测出故障线路，对两端数据的同步性要求不高。

Fault Detection of Transmission Lines Based on Fault Component of Positive Sequence Current

The setting of traditional backup protection in high voltage transmission system is difficult, and its sensitivity is easily affected by high resistance grounding and power flow transfer. A fault detection algorithm for transmission lines based on fault component of positive sequence current is proposed. The ratio of vector and amplitude of fault component of positive sequence current to vector difference amplitude at both ends of the line is used as the fault judgment quantity of the line. The strict formula deduction is given and the criterion of fault detection is established. Distribution characteristics of line fault judgement are analyzed theoretically, and its relationship with the line impedance, the system equivalent impedance at the back of both ends and the location of fault points is discussed. It is proved that the fault judgment is independent of transition resistance. In case of system oscillation, the fault location value is taken as an auxiliary criterion. Simulation results of the IEEE 39-bus system show that the proposed algorithm can detect the fault line correctly when all kinds of faults occur, and it is not affected by fault location and transition resistance. The fault line can also be detected when non-full-phase operation and load flow transfer occur. The algorithm does not require very high synchronization of data at both ends of the line.