An Improved Calculation Method for the Wide Frequency Admittance Parameters of Transformer Based on FEM

The calculation of the admittance parameters of the power transformer is the basis of establishing its black-box model and studying its freqency response analysis. An improved calculation method for wide frequency admittance parameters is proposed based on multi-conductor transmission lines model, combined with the finite element method. Firstly, multi-conductor transmission lines model of the transformer windings is established. In order to reduce the order of the parameter matrix, several turns which are continuous in capacitive coupling are treated as a transmission line by applying finite element method. Then after the boundary conditions are applied to the model, zero and non-zero values of the matrix are separated to calculate respectively, which avoids the complex equation solution of the previous calculation method, as well as improves the computational efficiency. At last, a 10kV single-phase two-winding transformer is measured. By the comparisons of the calculated and the measured results the method is proved to be validation.