Y,d接线变压器三角形侧绕组中环流求取方法  

Calculation of Circulating Current in Delta Winding of Transformers with Y,d Connection

作　　者：夏石伟[1] 郑涛[1] 

机构地区：[1]华北电力大学电力系统保护与动态安全监控教育部重点实验室,北京市102206

出　　处：《电力系统自动化》2008年第24期60-64,共5页Automation of Electric Power Systems

基　　金：国家自然科学基金资助项目(50607006);长江学者和创新团队发展计划资助项目(IRT0515)~~

摘　　要：采用Y,d接线的变压器三角形侧绕组中的环流难以测量,因此变压器差动保护存在相位补偿的问题。文中根据变压器等效电路的微分方程,推导出三角形侧绕组环流和星形侧零序电流的比例关系。并利用选相位关合技术,控制A相90°合闸,得到与一部分环流近似相等的A相线电流,利用波形相关度理论,求取A相线电流和星形侧零序电流的相关系数,以区分A相线电流受涌流影响的部分和未受影响的部分,求出比例系数,进而可由星形侧零序电流求得三角形侧绕组环流。最后通过MATLAB仿真和RTDS试验验证了该方法求取三角形侧绕组环流的准确性。It is difficult to measure the circulating current in delta windings of Y, d connected transformer. So the current phase compensation has to be considered for transformer differential protection. In this study, a proportional relationship between the zero sequence current in Y winding and circulating current in delta winding is derived based on the differential equations of transformer. If phase A is closed exactly in 90° by controlled switching, the part of the line current of phase A is almost equal to the circulating current. By using the correlative formula, the correlative coefficient of line current of phase A and zero sequence current in Y side is calculated so as to distinguish parts of line current, with and without influence of inrush. Then the ratio between the zero sequence current and the circulating current, and the circulating current can he calculated as well. Finally the algorithm is verified with MATLAB and RTDS simulation. The results show that the calculated circulating current is identical with the actual one accurately, and it offers a new algorithm method for the differential protection and the equivalent transient inductance.

关 键 词：变压器差动保护 励磁涌流 环流 选相位关合 

分 类 号：TM772[电气工程—电力系统及自动化] TM42