Analysis of series compensated self excited induction generators for autonomous power generation

The paper presents an analytical technique to predict the steady state performance of a 3-phase self excited induction generator for autonomous power generation which employs both shunt and series capacitors for voltage regulation. The system is modeled using an equivalent circuit which interconnects the machine, capacitor and the load. Simplifying appropriate loop equations of the circuit leads to two nonlinear equations in the unknown quantities namely the saturated magnetizing reactance and the generated per unit frequency for the given machine parameters, speed, capacitors and load. A numerical method based on the Newton-Raphson technique is developed to solve these equations to predict the performance. The validity of the method is evaluated by computing predicted and experimental results on a laboratory machine. Performance results under different operating conditions are detailed, to study the effect of series compensation in practical realization of such systems.