Characteristics of a stand-alone induction generator in small hydroelectric plants

This paper proposes a simple method of evaluating the steady state characteristics of a stand-alone induction generator driven by a small hydro-turbine. The steady state operation of the generator is first described by a set of nonlinear equations using the conventional loop impedance approach. The torque-speed characteristic of the hydro-turbine is then carefully incorporated into the generator equations. The ultimate set of equations is solved using a numerical based routine ldquofsolverdquo given in the optimization toolbox of MATLAB. The effectiveness of the proposed method is then evaluated on a 1.5-kW, 220-V, three-phase induction generator. Simulation results obtained by the proposed method are compared with the corresponding actual values found through an experimental setup. The steady state characteristics of the generator for regulated (constant speed) and unregulated (variable speed) operations are also compared.