Modeling Minimally-Processed Shielded Metal Arc Weld Transformers for Rural Minigrid Applications

This paper describes a detailed nonlinear electromagnetic model for predicting current in transformers commonly used to supply electrical power in rural arc welding applications. Current-limiting in these welders during quenched arcs is achieved using a gap-less core design, resulting in high-magnetizing impedance but also a significant degree of magnetic saturation. To accurately predict transformer currents during arc welding, the proposed model includes nonlinear magnetization effects. Parameter identification of the magnetic properties of the transformer core is performed using a population-based search algorithm using open-circuit transformer measurements. The model is validated using measurements on an experimental transformer during live arc weld testing.