Characteristics of Jiles-Atherton model parameters and their application to transformer inrush current simulation

We describe a time-domain simulation technique for nonlinear hysteretic transformer behavior based on the Jiles-Atherton model but with variable parameters. The normal Jiles-Atherton model assumes its parameters are independent of the applied maximum (peak) magnetic field intensity H-max. In this paper, we demonstrate that these parameters vary with H-max for a ferromagnetic material commonly found in transformers and we also propose a technique for modelling transformer behavior when H-max is rapidly changing. We present examples of inrush current simulation for transformer protection research and compare them with expierimental measurements, demonstrating that the proposed algorithm is robust and accurate.