基于行波差动原理的线路保护实用判据

纵联电流差动保护用于长距离输电线路时,会受到分布电容电流的影响。基于输电线路的分布参数模型,分析了分布电容电流与方向电流行波传输延时的等价性,研究了传统行波差动保护的实现方式,提出一种基于行波差动原理的实用保护方案。该方案利用同侧电流的实测值和计算值构成差动判据,在获取电流计算值时,无需进行插值计算,也不需要对侧电压信息,从而减小了计算量,降低了对采样率和通信速率的要求。ATP仿真表明,该方案能够有效地消除分布电容电流的影响。

Applied Criterion for Line Protection Based on Traveling-wave Differential Principle

When using for long distance transmission lines,the current differential protection suffers from influence of the distributed capacitive current.Based on distributed parameter line model,equivalence of the distributed capacitive current and the directional current traveling-wave transmission delay is analyzed and implementation mode of the traditional traveling-wave differential current protection is discussed.Furthermore,an applied protection scheme based on traveling-wave differential principle is proposed.The new scheme forms a differential criterion with the measured and the calculated current values of the same side of the line.When calculating the current,it needs not to use interpolation or voltage of the opposite side,which results in less computation and lower demand of sampling and communication rate.Simulation with ATP shows that the new scheme can eliminate the impact of distributed capacitive current effectively.