Modeling three-phase saturable transformers for real-time simulation

This paper presents a method to model three-phase saturable transformers for real-time simulation, using the example of a wye-delta configuration. The magnetizing path of the transformer is modelled with parallel connected linear inductors to simulate a piecewise linear saturation characteristic. Depending on the saturation state, the inductors are switched on and off via ideal switches, which are modelled via parametrized curves. An efficient implementation is proposed for real-time simulation. The simulation offline on the PC, online on the realtime target with a step size of 50us and the application on a wind turbine converter system validate the method. The achieved results demonstrate the performance of the method.