三绕组电力变压器单相接地短路电流及绕组强度计算

Calculation of Single-phase Grounding Short-Circuit Current and Winding Strength of Three-winding Power Transformer

本文针对三绕组电力变压器中压绕组单相接地短路问题,首先建立了三维有限元模型,利用场路耦合有限元方法对该模型进行三维瞬态分析;其次计算得到中压绕组单相接地时的短路电流、绕组漏磁场及电磁力分布情况;最后将计算得到的电磁力结果导入到结构场计算模型中,对变压器遭受该短路工况时线饼位移及应力变化进行瞬态动力学分析。计算结果表明,利用该方法对该工况下的电流电动力的计算较为合理且提高了计算精度,对分析变压器绕组短路强度有一定的参考价值。

Aiming at the single-phase grounding short-circuit problem of the medium-voltage winding of the three-winding power transformer,this paper establishes a threedimensional finite element model,and uses the field-circuit coupled finite element method(FEM)to perform a three-dimensional transient analysis of the model.Secondly,Short-circuit current,winding leakage magnetic field and electromagnetic force distribution are obtained.Finally,the calculated electromagnetic force results are imported into the structural field calculation model,and the transient dynamic analysis of the displacement and stress changes of the wire cake when the transformer is subjected to the short-circuit condition.The calculation results show that the calculation of the current and electromotive force under this working condition by this method is more reasonable and the calculation accuracy is improved.It has certain reference value for analyzing the short-circuit strength of transformer windings.