Research of restraining of transformer excitation inrush current based on improved series closing resistance

Based on using closing resistance to reduce transformer excitation inrush current produced in underloading and no-load, an improved method of in series with capacitor on closing resistance was proposed. The method connects capacitors in series with the original closing resistance, and selects suitable capacitor value, so as to restrain excitation inrush current and accelerate attenuation speed of the excitation inrush current. Combining with split phase closing techniques, the method can restrain the transformer excitation inrush current greatly. The simulation results validate feasibility of the method.