克服距离保护暂态超越的新方法

暂态超越现象的存在，使得距离保护Ⅰ段的作用受到很大限制，保护范围大大缩小。分析了电容式电压互感器（CVT）和电流互感器（TA）的传变特性，指出了由于CVT和TA传变特性不一致引起的二次侧电压电流非周期分量无法平衡是导致距离保护暂态超越的根本原因。在微分方程算法的基础上，提出了一种通过在电压互感器二次侧叠加一个综合的衰减非周期分量使二次侧电压电流非周期分量基本平衡，从而提高保护精度、改善暂态超越的新算法。由于使用了最小二乘拟合算法，该算法自身就具有很好的滤波特性。经过EMTP仿真和实际现场数据验证，证明了该算法原理上的正确性和可行性，有很好的实用价值。

Novel Algorithm for Overcoming the Transient Overreach of Distance Protection

The transient overreach phenomenon reduces the sensitivity of zone one protection of distance relaying. By analyzing the transient response characteristics of CVT and current transformer, this paper points out that the disaccord between CVT and current transformer of the non-period components transfer characteristics is the main reason of transient overreach. Hence this paper presents a novel method based on the differential equation algorithm. The algorithm superposes a synthetically attenuation non-period components to voltage in the secondary side of CVT that makes the non-period components of voltage and current in the secondary side nearly identical. So the calculation accuracy of fault distance is enhanced and the transient overreach phenomenon is ameliorated. The method has filtration capability because the least square fitting algorithm is used. The EMTP and fault record data simulation results show the correctness and feasibility of the proposed algorithm.