独立电力系统故障分量差动保护的仿真分析

Study on Fault Component Differential Protection for Isolated Power System

由于空间的限制,独立电力系统的电缆都相对较短,对于每一级线路,线路始端和线路末端短路时流过继电器的短路电流基本相等,传统的时间电流原则保护方法已不能满足其有效保护的要求。利用故障分量差动保护对相对独立的系统进行了PSCAD仿真并进行了MATLAB软件实验。结果表明,与传统的三段式电流保护方法相比,故障分量差动保护能有效地区分内部、外部短路故障,且相比全电流差动保护也有很好的抗过渡电阻能力,满足独立电力系统线路有效保护的要求。

For the space restriction in isolated power system, the cable is respectively short .To each level cable ,the short current to the beginning and end of line is approximately equal over relay.The traditional time current principle can’t satisfied the effective protection. By using longitudinal differential protection method,the generators parallel connection system is simulated in PSCAD/EMTDC and the differential current protection is experimented in MATLAB .The research shows that the fault component differential protection has good ability against transient resistance, which also can distinguish internal and external faults effectively,satisfy the requirements of the elements（line and bus） effective protection.