基于Hausdorff距离的自适应母线保护新原理

A Novel Criterion of Adaptive Busbar Protection Based on Hausdorff Distance Algorithm

传统基于工频量的差动式或比相式母线保护装置受滤波算法数据窗影响动作速度较慢且原理上无法摆脱电流互感器(current transformer,CT)暂态饱和带来的不利影响。为此,提出了一种基于Hausdorff距离算法的自适应母线保护新原理。首先给出了Hausdorff距离算法的基本原理,然后将与母线相连任一支路电流与其余各支路电流之和进行采样值同步及标幺化处理,接着分析了两者Hausdorff距离在不同系统工况下的变化规律,据此提出设置2个门槛值将动作平面划分为三区域以自适应区分内、外部故障及CT饱和情况。理论分析和基于PSCAD/EMTDC的仿真结果表明,所提新判据动作速度快、抗CT饱和能力强、灵敏度高,门槛值整定简单且对系统不同运行方式能做到可靠自适应。

The conventional differential or phase-based busbar protection device based on the power frequency has the disadvantage of slow operation speed because of the filtering algorithm data window, and it cannot get rid of the adverse effects caused by the saturation of the current transformer(CT). To this end, this paper proposes a new adaptive busbar protection criterion based on Hausdorff distance algorithm. Firstly, the basic principle of Hausdorff distance is given. Then, the current of any one of the branches connected to the busbar and the sum of the currents of the other branches connected to the busbar are both transformed to per unit. Finally, the variation of Hausdorff distance algorithm under different system conditions is analyzed. Accordingly, two settings are proposed to divide the action plane into three regions in order to distinguish between internal faults, external faults and CT saturation. Theoretical analysis and simulation results based on PSCAD/EMTDC show that the proposed new criterion has a fast operation speed, a strong anti-CT saturation ability, high sensitivity, and simple threshold settings and it is reliably adapted to different operating modes of the power system.