能够防止一点接地导致继电保护误动的安全型直流绝缘监测系统

通过对电力直流系统一点接地导致的继电保护误动的机理分析,提出基于系统电容分析的直流系统安全性评估方法。结合一点接地引起继电保护误动的条件和国家电网十八项反事故措施要求,提出在直流绝缘监测中控制负极对地电压的安全性设计措施,主要包括单臂检测电桥和临时修正电桥。对具体实施方案及相应的算法进行了描述,并依据安全性评估方法及安全性设计措施,设计出能够防止一点接地导致继电保护误动的高安全型的直流绝缘监测系统。

A safety DC insulation monitoring system which can prevent protective relay misoperation because of one point earthing

Through the mechanism analysis of protective relay misoperation because of one point earthing in power DC system, this paper proposes safety assessment measures based on system capacitance analysis. Combined with conditions of protective relay misoperation caused by one point earthing and State Grid eighteen anti accident measures, it proposes safety design measures that control negative voltage to earth in DC insulation monitoring system, mainly includes the single arm detection bridge and temporary fixed bridge, and describes the specific implementation plan and corresponding algorithm. According to these measures, a higher safety DC insulation monitoring system is designed which can prevent protective relay misoperation because of one point earthing.