An inrush current elimination technique for line-interactive UPS systems during switching-in of an auxiliary load while feeding a main load

Most industrial facilities involve use of various types of auxiliary loads in addition to a main sensitive load. Each of these loads are generally accompanied by load transformers. As these auxiliary loads are switched-in, their transformers also become energized. An inrush current often develops when the transformer is switched-in. This paper proposes an inrush current elimination technique for line-interactive UPS systems during the switching-in of auxiliary load transformers by utilizing a fast acting current regulated voltage source inverter. The proposed inrush current elimination technique is validated by simulation results.