小电流接地系统相间距离保护的误动分析及防范措施

Mal-operation analysis and its preventive measures of phase-to-phase distance protection of small current grounding system

为满足小电流接地系统复杂网络保护之间的整定配合问题,采用相间距离保护替代过流保护。当系统发生相间短路故障时,非故障相相间距离保护元件因负荷电流、线路长度的影响,导致距离保护元件在某种情况下落入动作区域。本文结合现场相间距离保护动作案例,对相间距离保护的动作特性进行了深入分析,并提出了相应的解决方案。

In order to solve the setting match problem, the phase-to-phase distance protection is adopted in the complex network of small current grounding system instead of overcurrent protection. When the interphase short circuit fault occurs in the system,the phase-to-phase distance protection elements of nonfault phases that influenced by load current and line length will fall into the action area under certain circumstances. Combining with the site cases,the action characteristics of phase-to-phase distance protection are analyzed deeply and the corresponding solutions are proposed in this paper.