유도발전기 직입 기동에 적합한 변압기의 용량 산정에 관한 연구

Abstract

Induction generators have the advantages of simple structure, low cost, and easy maintenance, like induction motors. So, Induction generators are often used in small hydro power plants where the output of the generator is not high. The induction generator has a drawback that it causes a voltage drop due to a high inrush current when the induction generator is directly inserted and is connected to the system like the start of the induction motor. When a voltage drop occurs in the same bus line, it may affect the devices connected in parallel and prevent them from operating, or cause a malfunction. In order to reduce the influence of the starting current of the induction motor or the inrush current of the induction generator, a number of studies have been proposed that have proposed various starting methods. The current reduction method for reducing the voltage drop is the addition of another starting system for the induction motor and induction generator.<BR> In this study, using the method applied for calculating the capacity of the emergency generator, the capacity of the transformer connected to the system after the direct starting of the induction generator was calculated considering the magnitude of the voltage drop. As a result of analysis, it was confirmed that the voltage drop on the primary side of the transformer was very low, but the secondary side of the transformer had a large difference in the voltage fluctuation rate depending on the transformer capacity.