An experimental investigation of self-excitation in capacitor excited induction generators

Self-excitation process in induction generators is a complex physical pheno menon, that has been studied extensively in the past. In-depth coverage of methods of steady-state analysis and models for simulation of transients is provided in the existing literature. Reports regarding experimental invest igation of dynamics are however much less detailed. Usually, their only pur pose is to prove the theoretical concepts. This paper attempts to fill in t his gap by providing a purely experimental treatment of the self-excitation process in induction generators. The emphasis is placed on situations that lead to voltage collapse and total demagnetisation of the machine, and on variable speed operation of the induction generator with a fixed capacitor bank. Operation with capacitors connected in star and delta under no-load c onditions, connection of the purely resistive load, and connection of the r esistive load with short-shunt compensation are elaborated. It is shown tha t some of the commonly quoted features of a self-excited generator operatio n do not necessarily hold true, while others are confirmed. (C) 2000 Elsevi er Science S.A. All rights reserved.