## Matrix Algorithm for Ladder Network Frequency Response Analysis of Double-Winding Power Transformer

**REN Fuqiang;JI Shengchang;ZHU Lingyu;LIU Yong;YANG Fan;LU Weifeng;LI Xining;State Key Laboratory of Electrical Insulation and Power Equipment,Xi'an Jiaotong University;**

To improve the incomplete transformer winding model in the circuit simulation software or the low efficiency of frequency response calculation due to many unknowns in the existing algorithm,a research on a matrix algorithm to calculate the frequency response of the equivalent ladder network for double-winding transformer is conducted.Following the equivalent circuit topology,the model is completely described by the impedance branch matrix and the admittance branch matrix.By means of matrix operation,the relationships of the column vectors of impedance branch current and admittance branch current with nodal voltage are obtained.The frequency response of the equivalent circuit model is calculated by solving the nodal voltage column vector.A comparison between the simulated results of matrix algorithm and those obtained by circuit simulation indicates that the correlation coefficient(CC)becomes greater showing good agreement between them.The curves without high amplitude resonance peaks(above-500 dB)coincide perfectly with a CC of 10.The matrix algorithm takes less calculation time than simulation software.Ensuring the integrality and precision of the simulation model,the proposed algorithm is endowed with good computational accuracy and efficiency due to only twicematrix inversions and less unknowns to be solved.

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