Steady-State Analysis of Three-Phase Self-Excited Induction Generator for Stand-Alone Applications

Abstract

Self-excited induction generator offers certain advantages over a conventional synchronous generator as a source of isolated power supply. Main advantages are reduced cost, less maintenance, self protection from short-circuit or overload condition, and brush less rotor. It is used as variable speed generator for different applications such as wind energy conversion, micro hydropower generation. Therefore, it is now a key interest to develop an efficient and viable Generator for harnessing the energy from renewable sources. To develop an efficient, viable, economic and controllable induction generator, we must know the steady-state performance of the generator. Using steady state equivalent circuit model excluding iron losses, steady state performance analysis has been done. Experimental investigations under steady state condition have been done in the laboratory. Keywords: Minimum capacitance, standalone SEIG, self-excited induction generator, remote areas, rural areas, steady state analysis, operating conditions. I.INTRODUCTION Electrical energy is the basic necessity of any country for its overall development. Fossil fuels (Coal, Oil, and Diesel) are the main sources of electrical energy (about 60% in our country). Fast depletion of fossil fuels results insecurity of availability of fossil fuels, subsequent increase in energy cost, the environmental pollution and above all the global warming. This has brought the worldwide attention in reducing the pollution and conservation of the limited conventional fuels by encouraging more and more use of the energy available from the non-conventional/renewable sources such as the wind, the biogas, the tidal waves and the small hydro power stations on the running canals and rivulets etc. The potential of the energy available from the small hydro and the wind sources seems to be quite promising to meet the future energy demands, especially in the remote and isolated areas. However, these systems will become more viable if their cost is reduced to the minimum. Therefore, the squirrel cage rotor induction generators are receiving much attention for such applications due to its low cost and robust construction[1-4]. The Self-Excited Induction Generators (SEIGs) are receiving increased attention from the utilities over the world to obtain the energy from renewable/non-conventional sources for remote and isolated areas. The main problems in the use of induction machine as a generator are related to the varying voltage and frequency, the loss of self-excitation, the overloading of the machine, the transient over voltages due to the capacitance switching or the load loss. But, the robust construction of induction machine specially squirrel cage type rotor, offers maintenance free operation and the least cost of the generating system. This has motivated to facilitate the use of the induction generator in isolated mode with suitable low cost control which could ensure the reliable supply of good quality. Also, such system for power generation could be made efficient and c...