Effects of Iron Core Materials on a Single-phase Power Transformer during Out-of-Phase Synchronisation in MicroGrid

Phase locked loop (PLL) is usually used to synchronize microgrid voltage and grid voltage. However, when the detection element fails, the possibility of asynchronous switching still exists. In this paper, the finite element method is used to study the influence of core material on the performance of single-phase transformer. In the past OOPS impulse current analysis, the saturation of transformer is ignored, which is not feasible. The BH curve of the core material and the position of the switch are very important to the electromagnetic transient process of the saturated transformer. The results show that the impact current, core permeability and magnetic field are closely related to the switch position and core material. At the same time, the harmonic components of impulse current of power grid and generator are analyzed.