低压厂用系统保护的整定配合

系统介绍了低压侧中性点直接接地的低压厂用工作变压器和备用变压器的过流保护，低压侧分支过流保护和零序电流保护，以及低压电动机电流保护的整定计算和保护配合，指出了以前整定计算中存在的不足，以及断路器保护与邻接回路保护的配合要求。介绍了断路器之间的保护和继路器至熔断器之间保护的配合方法，以及选择性试验。对一些重要环节保护配合还作了简单扼要的提示说明。

The setting and cooperation of protections for LV auxiliary power system

The setting and cooperation of the over current protections for low voltage (LV) auxiliary transformer and stand by transformer with neutral point grounding directly,the over current and zero sequence current protection for transformer low voltage branch,and the over current protection for low voltage motor are introduced.While the problems existing in the old protection setting calculation are pointed out,the cooperation requirements of breaker protection and circuit protection is introduced.The cooperation methods between breaker protections and between breaker protection and fuse protection and the selectivity check are introduced.The protection cooperation for some important links is explained briefly.