分析了超高压同塔四回线长距离输电线路分布电容对传统电流差动保护的影响。在此基础上，考虑同塔四回线相间及线间的电磁耦合，建立对应频域及时域下的同塔四回线12序(模)分量Π型等值电路模型，并基于各序(模)量等值电路分别提出频域及时域电容电流补偿方法。对无电容电流补偿，频域相量电容电流补偿及时域电容电流补偿等不同电流差动保护方案动作性能进行对比，结果表明在不同运行条件下采用时域补偿具有更佳的保护性能。%Based on the study about the influence of the distributed capacitance current of long-distance four-parallel lines on same tower on differential current protection, the Pi-mode circuit for the twelve-sequence (mode) networks is established. On this basis, the paper presents a novel time-domain capacitive current compensating algorithm and phasor capacitive current compensation method. Both of two capacitive current compensating algorithms take account of the electromagnetic coupling between the lines. It comparatively analyzes the characteristics of current differential protection schemes such as non-capacitance current compensating, phasor-domain capacitance current compensating and time-domain capacitance current compensating. Simulation results verify that the setting value of differential protection and selectivity and sensitivity of differential protection have been obviously improved by using the time-domain capacitive current compensating algorithm.
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