适用于特高压线路的差动保护分布电容电流补偿算法

从行波传播的角度分析了分布电容电流的形成机理,在此基础上提出了基于电流行波的新 型分布电容电流时域补偿算法。新算法对于故障暂态和稳态过程中所产生的电容电流具有同样的 补偿效果,而且不需要提高采样频率,不增加数据通信量。当线路内部无故障或线路中点发生故障 时,新算法能完全补偿电容电流;当线路其他位置发生故障时,能够使动作电流与制动电流之比与 电容电流被完全补偿时近似相等,从而有效地消除了分布电容电流对差动保护的不利影响。理论 分析和仿真结果表明该补偿算法可应用于普通的特高压线路纵联差动保护。

Distributed Capacitive Current Compensation Algorithm for Current Differential Relay of UHV Transmission Line

This paper investigates the mechanism of distributed capacitive current by using the traveling wave theory and presents a novel distributed capacitive current time-domain compensation algorithm based on current traveling wave. The proposed algorithm has the same compensation effect for the capacitive current under both transient and stable operating condition and needs not to increase the sample frequency or the telecommunication traffic. While the protected line is subject to no internal fault or a midpoint fault, the algorithm can fully compensate the distributed capacitive current. When a fault occurs at other points of the protected line, the proposed algorithm produces the approximately same ratio of the operating current to restraining current so as to fully compensate the capacitive current. The algorithm can effectively eliminate the adverse influence of distributed capacitive current on the current differential relay. EMTP simulation results demonstrate the validity of the novel algorithm.