3상 유도기의 전동 운전과 발전 운전 모드에서의 무효전력 특성 분석

Abstract

Induction machines can be operated as motors or generators near synchronous speed and it must be continuously receive the reactive power which is required for magnetization from the power supply side to maintain the rotating magnetic field regardless of the operation modes. If an induction machine with the same output capacity is operated as a motor or generator, the magnitude of the active power in each operation mode is different each other because the input and output are opposite to each other. When the active power changes, the reactive power also fluctuates, but the reactive power is slightly higher when operated as generator than when operated as motor. This is the reason why the power factor is slightly lower when the induction machine is operated as a generator than when it is operated as a motor. In this study, the magnitude of reactive power were calculated at each operation modes and analyzed how the ratio of reactive power changes when operated as a motor and as a generator for each capacity of the induction machine. The results are expected to be used as design reference data for selecting the optimal capacity of capacitors to improve the power factor in motor and generator operation of induction machines in the future.