Stability Characteristics of Alternators

Abstract

Synopsis.-During the pastfew years, stability characteristics of A series of curves and a formula for the minimum allowable systems using long lines have been discussed at considerable length, value of short-circuit ratio as a function of saturation and power but not so much attention has been given to the characteristics of factor are proposed for general purpose alternators which may be the load. This paper shows that power limits may be reached called upon to deliver power to any of the various classes of load. with very short lines and certain classes of load.These curves are derived from characteristic curves of typical The characteristics of several classes ofload, s.uch as motors of vari-machines. ous kinds with constant shaft output, variable impedance loads (syn-It is not intended that these curves shall be used for generators chronous converters for railways), constant impedance, and miscella-which supply power over long transmission lines, as the characterneous combinations, are discussed as they affect the stability of the gen-istics of these lines may require considerably higher values of shorterator. The criterions for the stability of an alternator as developed by circuit ratio, and the generator must be specially designed to meet this paper are "short-circuit ratio," saturation, power factor of the the individual requirements.