Capacitance requirements for the operation of induction generators in isolated power systems

Operation of an induction machine as a generator has been gaining ground in the last decades mainly because of its application in renewable nonconventional energy systems such as wind energy systems. One of the most popular applications of the induction generator is in isolated power systems with capacitor excitation. From electric machinery theory it is known that in order for an induction motor/generator to operate, it needs to be supplied with reactive power. When an electric grid is present, it provides the necessary reactive power to the generator. In isolated power systems, though, capacitor banks need to be connected to the machine terminals in order for it to be able to operate either as a motor or as a generator. During the startup of an isolated induction machine in particular, there is found to be a certain value of its exciting capacitance below which the machine will fail to selfexcite and successfully build up a voltage. This thesis is to investigate these capacitance requirements that isolated induction generators exhibit during their startup through theory, simulation and experiment. The author hopes this thesis will provide the tools necessary to study and evaluate the conditions for the successful startup of an induction generator when operating in an isolated power system.