电力系统振荡对三相故障距离继电器影响的分析及对策

Impact of power system oscillation on three-phase fault distance relay and countermeasure

针对发生对称性故障、系统振荡以及振荡中再故障三方面分析了三相故障距离继电器的动作性能;重点分析研究了在系统振荡再故障的情况下该继电器的动作特性,分析发现该继电器在此种情况下可能发生拒动;在此基础上提出了改进措施,引入了振荡再故障判断元件来启动姆欧继电器,有效提高了保护的可靠性。PSCAD仿真验证了理论分析的正确性以及所提方案的有效性。

The operational performance of three-phase fault distance relay is analyzed for three cases： symmetrical fault,power system oscillation and symmetrical fault during power system oscillation.It is found that the relay may refuse to act in the third case.Countermeasure is proposed：an element is introduced to detect the fault during power system oscillation and trigger the mho-relay,which improves the reliability of protection.Results of PSCAD simulation show the correctness of theoretical analysis and the effectiveness of the proposed countermeasure.