Mitigation of Transformer Magnetic Inrush Current

Abstract

At the time of transformer energization, a high current will be drawn by the transformer. This current is called transient inrush current and it may rise to ten times the nominal full load current of transformer during operation. Transformer inrush current is high magnitude and harmonic rich current. These current produces undesirable operations of the protective equipments in the power system. Due to these inrush current some undesirable operations may happen such as protective relays disoperation, loss of life of transformer potential damage, mechanical stress on the transformer and affects on the winding and bushing of transformer and reduce power quality. There are many sensitive electrical loads such as computer and medical equipments connected to the power system may disrupt. So the reduction and way to control transient current is important. There are different method used to minimize inrush current such as controlled switching ,virtual airgap techniques ,and prefluxing method. In this paper explains above written method of minimization of inrush current in the transformer