电力变压器低压螺旋绕组导线换位结构下电流分布特性  

Characteristics of Current Distribution Under the Transposition Structure in Low Voltage Helical Winding of Power Transformer

作　　者：赵毅 文韬[1] 倪鹤立 陈维江 张乔根[1] 傅中 ZHAO Yi;WEN Tao;NI Heli;CHEN Weijiang;ZHANG Qiaogen;FU Zhong(State Key Laboratory of Electrical Insulation and Power Equipment,Xi'an Jiaotong University,Xi'an 710049,China;State Grid Corporation of China,Beijing 100031,China;State Grid Anhui Electric Power Co.,Ltd.Electric Power Research Institute,Hefei 230022,China)

机构地区：[1]西安交通大学电力设备电气绝缘国家重点实验室,西安710049 [2]国家电网有限公司,北京100031 [3]国网安徽省电力有限公司科学研究院,合肥230022

出　　处：《高电压技术》2021年第9期3218-3225,共8页High Voltage Engineering

基　　金：国家电网公司科技项目(SGAHDK00SPJS1800262)。

摘　　要：在低压螺旋式绕组中采用换位结构未能完全消除绕组内环流,并联导线间的电流仍存在差异。分析换位结构下绕组电流分布特性是计算绕组短路电磁力的基础和前提。以往在计算短路电磁力时,往往忽略短路电流的分布特性。在考虑换位结构的基础上对两种110 k V变压器低压绕组的电流分布特性进行研究,发现低压绕组导线回路间电流差值与峰值电流平均值的比值最大可达8.67%。绕组结构变化引起的导线回路漏感抗差异是导致并联回路电流分布不均的主要原因。同时,计算获得了不同电流分布情况下低压绕组各线饼中导线受到的电磁力分布规律,发现电流分布不均匀程度越大,导线在换位前后电磁力改变量越大,最大可达5.9%。定义导线回路间电流差值与峰值电流平均值的比值为绕组电流分布不均匀系数,发现电流分布不均匀系数随高度hc、导线辐向宽度wc的增大而增大。通过比较了两种类型低压绕组中电磁力分布特点,对螺旋绕组结构设计提出了建议。该研究结果可为变压器设计过程中结构参数的选取和校核绕组短路稳定性提供参考。The transposition structures are widely used in low voltage(LV) helical windings. However, circulating current in these transformers can not be completely eliminated. Analysis of the current distribution is the basis of studying the distribution of the short-circuit electromagnetic force, whereas it is usually ignored in previous studies. In this paper, the winding transposition structure is taken into consideration, and the current distributions of two typical 110 k V transformers are studied. The ratio of the current difference between conductors to the average peak current can reach up to 8.67%.The main reason of uneven current distributions is that the change of winding structure may lead to leakage inductance difference. Besides, the distribution of electromagnetic force on conductors in each LV winding is positively related to the unevenness degree of current distribution. And the maximum ratio is up to 5.9%. The ratio of the current difference between conductors to the average peak current is defined as uneven distribution coefficient Ku, and the Ku is found to be bigger when increasing the conductor height hc or the conductor radial width wc. By comparing the electromagnetic force distribution characteristics of the two LV windings, suggestions are made for the helical winding structure design. The results can provide references for the selection of structural parameters and the verification of windings short-circuit stability in the transformer design process.

关 键 词：短路电流 换位结构 螺旋式绕组 导线间电流差异 短路电磁力 

分 类 号：TM41[电气工程—电器]