Self-excitation of autonomous generators: 1. Theoretical aspects

Abstract

This article shows that, in works devoted to the self-excitation, the notions of “hard” and “soft” self-excitation are used, first, to determine the degree of impact on the system; second, to determine the nature of the change in the output value under self-excitation; and, third, to determine the impact and nature of the change of the output quantity. This article explains that these terms need to be used only to determine the nature of the change of the output quantity. The article, drawing an analogy with s dc generator, proposes that the self-excitation conditions of an asynchronous generator be violated in two areas: the starter and auto generator (self-oscillatory). It has been experimentally proved that, in a demagnetized system (a weak starter), self-excitation of a dc generator is accompanied by an abrupt change of voltage; that is, there is a hard self-excitation mode. It was found that. after working in the alternator mode, the generator remagnetized (was a strong starter) and, during the second self-excitations, voltage changes are not observed. In this article, it is proposed to call such self-excitation, in which a strong starter in the form of residual induction gets rid of the “hard” nature of self-excitation, “pseudosoft.”