Transient Characteristic Analysis of Induction Motor at the Bus Transfer by Standby Power Supply at the Power Failure

Abstract

This paper presents a new method to successfully perform fast bus transfer to connect to the alternative power source in the event of a supply disruption. Generally, the load of a large induction motor is equipped with two independent power supplies to increase the stability of the power supply. When a power failure occurs, the voltage gradually decreases, but the current hardly flows immediately. When a voltage drop occurs due to a power failure, the speed of the motor starts to decrease. When the power is supplied by the backup power source, it is necessary to keep the torque level at a safe level because a large current may cause a serious excessive torque to the motor shaft. The induction motor requires stable power supply at all times during operation of the load. In this study, we propose a method to reduce current and torque by providing a current signal instead of a voltage signal as a breaker input signal in order to quickly switch the backup power source in the event of a power failure.