一起主变低后备保护误动原因分析及对策

The Reason Analysis and Preventive Measures for a Maloperation of Main Transformer Backup Protection

针对一起因RCS-9681CS微机综合保护装置五段复合电压闭锁方向过电流保护越级误动而扩大了事故停电范围进行了深入分析,重点结合供电部门电力系统继电保护设置和工矿企业变配电系统实际情况,调整完善RCS-9681CS微机综合保护装置复合电压闭锁方向过电流保护定值的整定、计算,说明了与下级配电站保护配合的解决办法。尤其是在变压器后备保护范围延伸与下级保护级差配合问题上,提出了适当调整各级保护的定值和延时级差,在满足电力系统继电保护一般要求条件下,要满足工矿企业供电线路短、用电负荷复杂突变、保护类型与装置多种多样等综合情况,在不改变原有电力系统与供配电系统保护配置前提下,对多级过电流保护中的各项启动条件分别进行了调整,实现继电保护应有的灵敏性、选择性。

In this paper, a case that over-current protection of RCS-9681 CS microcomputer integrated protection device with five section compound voltage blocking direction was carried out to extend the scope of power failure is analyzed. Based on the relay protection setup of power supply department and the actual situation of transformer and distribution system in industrial and mining enterprises,setting the constant values of the over-current protection value of RCS-9681 CS microcomputer integrated protection device with compound voltage blocking direction is adjusted and improved.The solutions to protecting and cooperating with subordinate distribution stations are put forward.In this paper, especially on the issue of the extension of transformer protection scope and the coordination of lower protection level, the viewpoint of adjustment of the fixed value and delay level of all levels of protection is put forward.The viewpoint that sensitivity and selectivity of relay protection should be realized by adjusting the starting conditions of multi-stage overcurrent protection separately without changing the protection configuration of the original power system is also put forward.