A Method for Reducing Inrush Current and Transient Overvoltage in Three Phase Capacitor Bank

Power quality and power factor correction is still the major challenges in the power system. Both these parameters are abruptly affected by the switching transient and faults that occur in power system network. Switching transient is common phenomena caused by capacitor bank present in power system. Energizing the capacitor that is present in the power system network causes inrush current and transient over voltage in the network, that is not only affects the quality of the power flow in the system but also affect the life cycle of capacitor bank as well as the circuit breaker. This paper deals with detail working of newly proposed system providing immense combination of resistance and reactance in the economical single static reactor connected through three phase isolated transformers at the time of charging of capacitor, through which it suppresses the energizing transient of 3 phase capacitors. In bypass mode, all the element of newly proposed system which consists of diode and IGBT start conducting simultaneously the surge voltage of primary side of isolated transformer exploit as short circuited and the secondary side's surge voltage approximately zero. Due to presence of freewheeling diode in the system, no surges in voltage appear across circuit breaker, due to which the life span of circuit and equipment increases. The proposed system is implemented in matlab/ Simulink to carry out the feasibility of proposed circuit.