基于故障分量的T接线路电流纵差保护新判据

摘要

The paper analyzes operation characteristics of super-imposed fault component based traditional differential protection principles in the complex plane.It points out that there are some limitations for traditional principles in ensuring sensitivity of internal fault and reliability of external fault.Thus, it proposes a novel current differential protection principle for T-type transmission line combining with current phase difference.Restraint unit of the proposed principle takes the role of drive and restraint respectively in the case of internal and external faults.Therefore, both the sensitivity and reliability of protection are improved.Theoretical analysis shows that the novel principle is superior to traditional principles in ensuring sensitivity of internal fault and reliability of external fault.Besides, the proposed principle also have excellent performance under the condition of current transformer saturation.Simulation tests show that the proposed principle is valid.%分析了基于故障分量的传统差动保护在复平面上的动作特性,指出传统原理在保障内部故障的灵敏性与外部故障的可靠性方面存在一定的限制.提出了结合电流相位差的T接线路电流差动保护新原理,实现了制动项在区内外故障分别体现为驱动和制动两种状态,同时提高了差动保护的灵敏性和可靠性.理论分析表明新原理在内部故障的灵敏性和外部故障的可靠性方面均优于传统判据,具有良好的抗电流互感器饱和性能.仿真实验证明了新原理的有效性.