Automatic voltage regulator for an induction generator

Abstract

In previous investigations of the operation of capacitorexcited Induction generators^ the size of capacitors in the network coupling the load to the generator have been selected by trial and error., and a satisfactory coupling network has never been developed. It was attempted herein to develop a satisfactory coupling network by choosing the capacitors in the sizes required to accomplish definite results. There were three preliminary steps: (1) The induction generator terminal characteristic was determined experimentally and verified. (2) A method of analyzing and predicting the effects of various coupling networks was conceived, used, and verified. (3) It was proved that series -capacitor-coupled induction generators will produce sustained fault currents. A network for coupling unity power factor loads to an induction generator in such a manner as to maintain constant load voltage was developed, analyzed, and tested, but the test results do not permit conclusive evaluation. An attempt was made to develop a coupling network for variable inductive loads to produce coarse voltage regulation so that fine control could be achieved with a smaller D-C controlled saturable reactor than would be needed otherwise. Such a network was devised, and the optimum parameter adjustment was determined by analysis. The network was tested and found to produce coarse voltage regulation; however, it was found that the use of this network does not appreciably reduce the size of the reactor needed for fine control of voltage . This network does have value in protecting the load and generator from harmonic currents a.rising from the use of the reactor, and it is recommended as the basis for the design of an automatic voltage regulator with a slightly different adjustment of parameters