基于双端电气量的同杆平行双回线单线故障测距

考虑同杆平行双回线零序互感的影响，针对同杆双回线单回线故障，提出了一种基于故障线双端电气量的故障测距算法。该算法根据同杆平行双回线单回线内部故障的等效序网图，利用相应故障类型在故障支路的电压边界条件导出其测距方程。算法利用了现有分相电流差动保护提供的单回线本端电压和两端电流工频量，原理上与过渡电阻和系统阻抗无关。通过PSCAD/EMTDC软件，仿真计算了不同过渡电阻、系统阻抗和负荷情况下不同故障点发生各种类型故障的测距情况。仿真测距结果表明，该算法应用于同杆平行双回线单回线故障测距时具有很高的精度，并与过渡电阻、系统阻抗和负荷工况无关。

Single Line Fault Location of Parallel Double Transmission Line on Same Tower Based onTwo-Terminal Electrical Quantities

To solve the problem of single line fault of parallel double transmission line on the same tower, by means of considering the influence of zero-sequence mutual inductance of parallel double transmission line a fault location algorithm based on two-terminal electrical quantities of the faulty line is proposed. According to the equivalent sequential network of faulty single line, the single line fault location equation is derived by use of the boundary condition of faulty line voltage under single line failure mode. In the proposed algorithm, the terminal voltage and two terminal power frequency currents offered by existing segregated phase current differential protection is adopted, so the principle of the proposed algorithm is independent of transition resistance and system impedance. The fault location of various types of faults occurred at different positions of single line under the condition of different transition resistances, system impedances and loads is simulated by PSCAD/EMTDC. Simulation results show that by use of the proposed algorithm the single line fault location of parallel double transmission line on the same tower is accurate, and it is also proved that the proposed algorithm is independent of transition resistance, system impedance and load situation.