Induction generators study on micro hydro plants generation

Abstract

Induction generator (in the truth, nothing more than na induction motor working as a generator) is a feasible option for generating eletricity in micro hydro plants, mainly by its low costs, such on purchasing as on maintenance, its construction simplicity and strongness when compared with a synchronous generator. Studies shows that the costs of an induction generator is up to 40% lower than a synchronous one. However, in Brasil, the use of induction generators connected to hydro turbines is on laboratorial tests level yet. This article, based on experimental results developed in Itajubá´s Federal University´s Small Hydro Plants Hydromechanical Laboratory – LHPCH-UNIFEI – proposes the use of asynchronous generatos connected to micro hydro turbines. Some theoretical basis that describes the mainly operational characteristics of induction generator (IG) are presented in this work, the voltage and frequency controll tecniques and the results of the tests accomplished in LHPCH-UNIFEI, where an induction generator connected to a pump working as turbine (PAT) was tested. A case study is also presented, comparing the costs of an PAT/IG and a Michell-Banki/synchronous generator generator group.