摘要
数字式变压器差动保护在星形侧发生外部单相接地或线路单相遭雷击的情况下,差动保护有时会误动。文中在深入分析矢量变换对差动电流影响的基础上,分析了变压器差动保护误动的原因,并提出基于零序电流补偿的三角形(△)侧向星形(Y)侧矢量变换的方法。该方法通过中性点零序电流和Y侧三相相电流的计算零序电流进行相位比较来决定是否消除Y侧的零序电流。最后通过实例证明了该方法的正确性。
Digital transformer differential protection may falsely take effective when external single-phase earth fault occurs at star side or the line endures lightning strike on single phase. Based on analyzing the influence of vector transformation on differential current, this paper analyzes the reason of this type of actions and proposes a new vector transform from delta side to star side with zero-sequence current compensation. Phase comparison of zero-sequence current at neutral point with measuring zero-sequence current at star side is therefore made to decide whether the zero-sequence current at star side is eliminated. Finally, two application examples verify the correctness of the proposed method.
出处
《电力系统自动化》
EI
CSCD
北大核心
2004年第5期56-58,共3页
Automation of Electric Power Systems
关键词
变压器保护
差动保护
Y
d矢量变换
零序电流
transformer protection
differential protection
vector transform
zero-sequence current
