Research On The Wideband Modeling And The Efficient Time Domain Computational Method Of The Transformer Windings

It is important to calculate the overvoltages of the transformer windings undervery fast transient overvoltage，a fast time-domain algorithm is presented based onthe time-domain finite element method (TDFE) in this paper， in which a hybridmodel is used consisting of multi-conductor transmission-line (MTL) and equivalentfrequency-dependent lumped impedance. By means of TDFE and vector fitting(VF)， the MTL telegrapher’s equations with frequency-dependent parameters arediscretized spatially， and the lumped impedance is converted into state equations.The resulting equations are solved by the backward differentiation formulas.Because of the convenience of dealing with the boundary condition of TDFE and thehigh precision of VF，the proposed algorithm can calculate the overvoltage along thewindings much more efficiently than traditional frequency-domain algorithm and theresult is verified by measurements of the winding model. Based on the Matlab,VC++and LabVIEW and using the mixed programming technique, a application forthe computation of the inner voltage of a transformer is developed.