Operation of induction generator in the magnetic saturation region as a self-excited and as a double output system

This paper presents the development of two dynamic models for simulating the operation of an induction machine with saturation considered, operating either as self-excited or as double output induction generator in autonomous wind systems. Both systems' steady state as well as transient performance during switching on and off from the bank of capacitors or the power line, respectively, is studied considering different wind speed and excitation conditions. A polynomial approximation of the variation of mutual inductance versus magnetizing current is used for the proper account of the effects of core saturation. The transient voltage and current built-up of the two systems, the harmonic distortion as well as the damping of the transient process are obtained from a laboratory autonomous wind generating system. From a comparison between the outputs generated by the two systems the results show that the double output induction generator can be installed for the better use of the wind energy.