Application of Capacitor for Starting a Large 3 Phase Induction Motor in a Stand Alone Grid

Abstract

Abstract-A standalone grid poses some quintessential and precarious problems of its own. One problem is the starting of large motors. While designing a standalone grid, a motor starting study is essential. This study is done to make sure the generator is capable of providing the starting reactive power required by the largest motor under the worst case. In one project, the generator in a standalone grid was incapable of delivering the required reactive power without increasing the generator rating. In that case, a variable frequency drive (VFD) starter was proposed to start the largest motor. This study investigates an alternative cost saving option for the same problem. The approach is to use capacitance during the motor starting. This compensates the starting reactive power requirements. This approach can be easily extended to micro grids, other standalone grids or captive generation. The study is performed using ETAP.