变电站直流系统总保险熔断问题分析及解决方案

Main problems and its countermeasures of the head fusing in power substation DC system

首先分析了变电站直流系统总保险熔断的四个主要原因:不同类型的设备混装;设备配置不合理或没有及时更新;没有执行直流熔断器定期更换的反措;设计思想上存在误区。特别对设计思想上存在的误区进行了理论分析。然后提出了改进思路:运用继电保护的思想,选择带有三段保护特性的直流断路器,逐级配合,愈靠近故障点的断路器动作时间愈短,保证选择性。最后,给出了具体工程设计主体方案。

This paper analyzes why did power substation DC system＇s head fusing. The probable reasons are the device mix： different types of devices, the device equipped unreasonable or unchanged in time with the increase of load, and the DC fuse unchanged regularly according to the correlative rule and some designing errors. This paper details the errors in designing scheme and proposes improved scheme. Based on relay protection, it chooses the DC circuit breaker with three zones protective characteristics and make them coordinated with each other step by step. The shorter distance between circuit breaker and fault point, the shorter time they need to use. So the selectivity can be ensured. At last, a specific principal part of the design project is put forward.