Extraction of winding parameters for 33/11 kV, 30 MVA transformer based on finite element method for frequency response modelling

Abstract

This paper proposes an alternative approach to extract transformer's winding parameters of resistance (R), inductance (L), capacitance (C) and conductance (G) based on Finite Element Method (FEM). The capacitance and conductance were computed based on Fast Multiple Method (FMM) and Method of Moment (MoM) through quasi-electrostatics approach. The AC resistances and inductances were computed based on MoM through quasi-magnetostatics approach. Maxwell's equations were used to compute the DC resistances and inductances. Based on the FEM computed parameters, the frequency response of the winding was obtained through the Bode plot function. The simulated frequency response by FEM model was compared with the simulated frequency response based on the Multi-conductor Transmission Line (MTL) model and the measured frequency response of a 33/11 kV, 30 MVA transformer. The statistical indices such as Root Mean Square Error (RMSE) and Absolute Sum of Logarithmic Error (ASLE) were used to analyze the performance of the proposed FEM model. It is found that the simulated frequency response by FEM model is quite close to measured frequency response at low and mid frequency regions as compared to simulated frequency response by MTL model based on RMSE and ASLE analysis.

Electromagnetic force distribution computations due to switching surge in disc-type winding

“…The RLC elements of the HV disc winding were computed through FEM via quasi-state Ansys Q3D and represented as RLC matrices according to [19]. The R matrix was established as the skin resistance of the winding conductor.…”

“…The AC resistance and inductance were estimated according to MoM via quasi-magnetostatic procedure. The turn-to-turn and inter-disc capacitances were computed based on MoM and FMM [19]. The turnto-turn capacitances for every turn has been computed based on [37].…”

“…The model involves the assumption that a pair of coils can be represented as a single capacitance. In recent years, electromagnetic models based on finite element method (FEM) have been introduced to support the modelling limitations on the geometrical and equivalent circuit models [16]- [19]. The transformer windings electromagnetic force measurements have been carried out in [20]- [23] with several simplifications and assumptions.…”

A Novel Approach for Evaluating Eddy Current Loss in Wind Turbine Generator Step-Up Transformers

“…The skin depth of penetration at fundamental frequency 50Hz may be calculated as follows in Eq. (18).…”

“…In this way, the inception of new formulae is recommendable and endeavor to enhance the computation and evaluation methods. A number of studies have been undertaken recently which take these objectives into account [16][17][18][19][20]. Thus, analytical techniques have demonstrated to be efficacious in computing the electromagnetic service losses.…”