基于同向量电流选相的电流平衡保护研究

针对传统平行双回线路电流平衡保护不能反应跨线故障的问题,提出了基于同向量电流选相的电流平衡保护方案。首先利用同向量电流突变量实现故障选相,并给出了两相短路与三相短路的判别方法。然后利用反向量与同向量的幅值比判别故障相是否为跨线故障。对于跨线故障相,利用单回线距离保护判别故障区域;对于单回线故障相,利用同名相电流的幅值大小进行选线跳闸。利用六序故障分量法分析了各种故障情况下的选相判据以及保护判据,并给出了保护流程。最后理论分析和ATP-EMTP仿真结果均验证了方案的正确性和有效性。该方案能够反应跨线故障,保护性能得到了改善。

Research on current balance protection based on same directional component current phase selection

Traditional current balance protection on double-circuit transmission line can not react to the interline fault, thus a current balance protection based on the same directional component current phase selection is proposed. First, the fault phase selection is realized by using the incremental quantity of the same directional component current. The discriminant method of two-phase short circuit and three-phase short circuit is provided. Then, the ratio of the opposite direction component current to same directional component current is used to judge whether the fault phase is interline fault. For the interline fault phase, the fault location is determined by distance protection of singe-circuit transmission line. For singe-circuit transmission line fault phase, the fault line selection is determined by the magnitude of the same-name-phase. The six-sequence fault component is used to analyze the phase selection criterion and the protection criterion under different fault types, and a specific protection process is proposed. The correctness and effectiveness of the proposed scheme are verified by both theoretical analysis and ATP-EMTP simulation results. The scheme can react to the interline fault and the protection performance is improved. This work is supported by Natural Science Basic Research Plan of Shaanxi Province of China (No. 2014JM7293) and Science and Technology Project of the Headquarter of State Grid Corporation of China (No. SGTYHT/16-JS-198).