Simplified measurement-based black-box modeling of distribution transformers using transfer functions

Modeling of power distribution transformers in the high-frequency range is of crucial importance in cases such as using power-line communication technology or investigating transient overvoltages at the transformer low-voltage side. This paper presents a simple black-box modeling methodology for distribution transformers using transfer functions defined by the recorded voltage ratios at the transformer terminals. The model parameters are estimated using an optimization method that minimizes the error between the measured and the calculated data. A significant advantage of the proposed methodology is the use of conventional instruments in conducting the measurements rather than high-precision and expensive equipment. The accuracy of the developed model is verified by its implementation in both frequency- and time-domain simulations.