不对称参数同塔四回线的综合横差保护方案

摘要

Due to the asymmetrical parameters of the quadruple-circuit lines, a new method for transverse differential protection and line selection is proposed. Fault super-imposed networks of the quadruple-circuit lines are discussed, and sequence currents of each line are also calculated during a fault. According to the characteristics of sequence currents obtained by the protector, negative- component based transverse differential protection approach is proposed. Different connection schemes of transverse differential protection are considered, and the setting values of the protection are calculated corresponding to different schemes. All the signals of all the protections are acquired by line selection to judge which line to be cut off. Simulation results have verified the reliability and feasibility of the negative-component based transverse differential protection.%考虑不对称同塔四回线的阻抗不对称特性，提出一种适用于不对称同塔四回线的综合横差保护方案，并根据所配置的综合横差保护方案的动作信号，给出了四回线的故障选线方案。分析了故障时同塔四回线的故障附加网络，基于故障时流经各回线的故障附加电流，构建了基于负序分量的两种横差保护方案，即小横差保护方案和大横差保护方案。讨论了不同接线方式下两种横差保护测量到的差动电流，给出了横差保护的整定方法，并综合保护的动作信号提出了基于横差保护的四回线的故障选线方案。PSCAD/EMTDC仿真结果表明，负序分量横差保护能够准确区分同塔四回线的区内、区外故障；在区内故障时，横差保护能够可靠动作，切除故障线路，具有较强的抗过渡电阻能力。仿真结果证明了保护方案的有效性与故障选线的可行性。