基于场路耦合法的高阻抗变压器设计与计算分析

Design and Calculation Analysis for High Impedance Transformer Based on Field-circuit Coupled Method

针对短路电流过大引起的变压器损坏问题,文中基于一台220 kV三相三绕组有载调压变压器产品,提出了3种提高中—低压侧绕组短路阻抗的设计方案。首先,通过拆分中压绕组、调压绕组中置、高压绕组内置的方法增大中低绕组间的漏磁空道,实现了3种不同绕组结构的高阻抗变压器设计;然后,应用基于场路耦合的有限元法和漏磁阻法分别对不同设计方案的短路阻抗进行计算分析,得出将高压绕组内置的方案对提高短路阻抗最明显,提高了124.56%。同时,通过两种方法计算结果对比验证了计算的正确性;最后,对不同设计方案引起的油箱及夹件的涡流损耗及损耗密度分布进行计算,研究在实现变压器高阻抗过程中对结构件损耗产生的影响。文中对今后高阻抗变压器的设计提供了一些思路。

Aimed at transformer damage caused by large short-circuit current,this paper presents three kinds of design scheme improving medium-low winding short circuit impedance based on a 220 kV three-phase three wind-ing load transformer product;First of all,through splitting the middle voltage winding,placing the regulating winding in the middle and the high voltage winding inside to increase the leakage magnetic gap between the low and middle windings,thus realizing the design of three kinds of high impedance transformer with different winding structure;Then,based on the field-circuit coupled finite element method and the flux leakage method,the short-circuit impedance of different design schemes are analyzed and calculated,and the results show that: the scheme of placing the high voltage winding inside is the most obvious improvement of short circuit impedance,which is im-proved by 124.56%. Meanwhile,the calculation results are verified by comparing the results of the two methods. Fi-nally,the eddy current loss and loss density distribution of oil tank and clip caused by various schemes are calcu-lated,and the effect of the loss of structure in the process of high impedance transformer is studied. This paper pro-vides some ideas for the design of high impedance transformer.