摘要
以广东某电厂发生的母线对主变压器和厂用变压器充电引起相邻发电机差动保护误动的事件为例,分析变压器励磁涌流引发和应涌流进而造成相邻发电机差动保护误动的机理。研究表明,发电机差动保护装置两侧的电流互感器型号及特性不一致,在长时间和应涌流直流分量的作用下,最终产生差动电流并达到保护动作值,导致保护出口跳闸。提出相应的改进措施:安装变压器智能合闸相位控制装置;差动保护整定计算时应考虑相邻变压器充电时引起的励磁涌流和和应涌流;降低剩磁;改善电流互感器的接入方式。实际应用效果良好。
The paper takes malfunction of differential protection of generators triggered by charge of main and auxiliary transformers with busbar in a power plant in Guangdong province and analyzes mechanism for sympathetic inrush caused by magnetizing inrush as well as malfunction of differential protection of generators.The research shows that current transformers at both sides of differential protection system are of different types and characteristics,which causes differential current and comes up to protection action value and thereby tripping at protection exit after long time and with effect from DC components of sympathetic inrush.The relevant measures such as installation of intelligent switch-on phase control set for transformers,setting calculation of differential protection in consideration of magnetizing inrush and sympathetic inrush caused by charge of adjacent generators,reduction of residual magnetism,improvement of connection mode of current transformers are brought forward and turn out to be effective.
出处
《广东电力》
2011年第4期42-45,共4页
Guangdong Electric Power
关键词
励磁涌流
和应涌流
电流互感器
发电机差动保护
误动
magnetizing inrush
sympathetic current
CT
differential protection of generators
malfunction
