高电压技术2011，Vol.37Issue(12)：3099-3106,8.
内桥接线方式下变压器差动保护误动原因及防范措施
Mal-operation of Transformer Differential Protection with Inner Bridge Connection and Countermeasure
摘要
Abstract
In the substation of inner bridge connection,two main transformers operate in parallel connection.The differential protection of normal operating transformer may mal-operate when the other transformer switching-on unloads through bridge breaker.Considering a case of mal-operation,we analyzed several influential factors on transformer differential protection,such as magnetizing inrush,sympathetic inrush,and current transformer（TA） saturation.It is concluded that TA partial transient saturation caused by the decaying DC component in magnetizing inrush is the main cause that results in the mal-operation of differential protection.By analyzing the mal-operation point,a new method of improving the threshold of ratio restraint characteristic is proposed to prevent differential protection from mal-operation in condition of transformers equipped with Siemens 7UT512 Numerical Current Differential Protection.Simulation results show the validity of analysis and verify the feasibility and practicability of the new modified ratio restraint scheme.关键词
变压器差动保护/内桥接线/TA饱和/励磁涌流/和应涌流/比率制动特性Key words
transformer differential protection/inner bridge connection/current transformer saturation/magnetizing inrush/sympathetic inrush/ratio restraint characteristic分类
信息技术与安全科学引用本文复制引用
黄少锋,谷君,郑涛,王增平..内桥接线方式下变压器差动保护误动原因及防范措施[J].高电压技术,2011,37(12):3099-3106,8.基金项目
国家自然科学基金（506070065077701650837002）~~ （）
