Recently, there has been an increasing application of squirrel cage induction generators to small hydro power plants due to their simple and rugged structure, low construction cost and easy of maintenance. Induction generators receive a large inrush current at the time of grid connection, which causes a drop in the system voltage. The remaining voltage must be high enough to ensure the starting current of the motor. Induction machines have been designed with a variety of rotor shapes with the aim of reducing the current. In this paper, we analyzed the effects of induction generator capacity in order to ensure that the voltage drop does not exceed the allowable range during connection to the grid connection system.