Flux-driven Nonlinear Transient Model for Single Phase Transformers

When transformers experience transient processes such as over voltage and switching, its port current exhibits significant nonlinear distortion. The magnetic flux distribution inside the transformer also changes when the current distorts. This means that the topology of the transformer's magnetic circuit and its parameters are also changing. To accurately reflect this change, this article proposes a topology selection method driven by magnetic flux. In time-domain simulation, the magnetic flux of the port is taken as the characteristic value, and different topologies are called based on the characteristic value. The nonlinear parameters in the topology can be derived from easily obtained nameplate data. Finally, the transient model was implemented in C++ and compared with the simulation results of PSCAD to verify its feasibility and accuracy.