Research on The Frequency Response Characteristics Calculation of Z-Type Transformer Winding Based on A Decomposition Algorithm

Abstract

To enhance the computational efficiency of frequency response for Z-type transformer windings with complex structures, an efficient decomposition algorithm for frequency response calculation is proposed, focusing on a lightning protection transformer with Yzn11 connection type. First, considering the structural characteristics of the equivalent circuit of the transformer winding, the equivalent circuit model is decomposed into three decoupled sub-networks. Then, the branch admittance matrices and incidence matrices of each sub-network are calculated. Subsequently, based on the interconnection relationships among the sub-networks within the entire network, the global nodal admittance matrix is constructed to establish a decomposition algorithm for frequency response analysis of the equivalent circuit of the Z-type transformer winding. Furthermore, the accuracy of the proposed method is verified with PSpice circuit simulation software. Finally, the superiority of the algorithm in terms of computation time is demonstrated by comparison with the traditional node voltage method. The results show that in terms of accuracy, the frequency response curves (six sets) of high- and low-voltage windings for phases A, B, and C obtained by the proposed method almost completely overlap with those simulated by PSpice. The correlation coefficients are larger than 0.999, and the comparative standard deviations are less than 0.7. The proposed method is superior to the traditional node voltage method in terms of computational efficiency. Especially, as the number of discs increases to 100, the computation time of the proposed method is reduced by 55.3%, and the calculation efficiency is significantly improved.