一种新的自适应突变量距离保护方案

针对传统突变量距离保护在两侧系统电势相位差较大时发生外部短路等情况有可能误动的缺点,借助同步相量测量技术提供的信息,研究了一种根据系统实时参数自适应调整保护动作门槛的新算法.首先分析了传统解决办法的局限性,通过理论证明,确定了原有判据发生误动的边界条件,在此基础上提出采用自适应门槛和判据切换的复合突变量距离保护新判据.对于保护区整定在本线路内的突变量距离保护,其动作可靠性和灵敏度得到了提高.ATP仿真结果验证了判据的有效性.

A Novel Scheme of Self-adaptive Superimposed Distance Protection

In order to overcome the defects in the conventional superimposed distance protection, for instance, the mal-operation resulting from an external earth fault occurring while the transmission system operates at large power angle, a novel self-adaptive superimposed distance protection scheme is proposed. By using the information provided from the wide area phasor measurement unit (PMU), this proposed scheme can adjust the operational threshold adaptively, in responding to the real-time parameter measurements of two equivalent power systems. After discussing the various limitations of conventional solutions, the boundary conditions of mal-operation for previous criteria are deduced theoretically. A new criterion of compound superimposed distance protection is put forward in which self-adaptive threshold is combined with criterion switching. By the virtue of above arrangement, the operation reliability and sensitivity of the superimposed distance protection are improved. The effectiveness of the proposed criterion is verified by the simulation results of ATP.