A Unified Magnetic Equivalent Circuit Model for Transformer Core Saturation Analysis in Multiphysics Simulations

The saturation model of the transformer is one of the core tools of multi-physics simulation. By combining it with multi-physics simulation, researchers can more comprehensively evaluate the performance of the transformer in actual applications. Geomagnetically induced currents (GIC) induce DC bias in transformers, leading to core saturation and a host of adverse effects. Traditional transformer models often struggle to accurately capture the behavior of the core under nonlinear saturation conditions. To address these challenges, a saturable transformer unified magnetic equivalent (UMEC) model which directly takes B-H magnetization curve to represent transformer core nonlinear characteristic is proposed. The saturable transformer model is based on the model of a magnetic circuit of transformer core. GIC effects on transformer saturation are also studied with the proposed saturable transformer and estimation method.