The development of modern excitation systems for synchronous condensers and generators

DURING the past 15 years and particularly in the past ten years, there have been many major developments in excitation systems for synchronous condensers and generators. These changes and improvements were stimulated in 1928 by the introduction of the hydrogen-cooled synchronous condenser which necessitated a reconsideration of the excitation arrangement and brought about a change from a direct-connected exciter to separate excitation. This, together with the desire to obtain maximum speed of response and to eliminate maintenance caused by moving parts associated with rotating exciters and with mechanical regulators, led to the trial of electronic applications on the systems of the American Gas and Electric Company A development program along these lines was carried on over a period of approximately 15 years and included specifically 15 exciter applications on large generators and condensers. About six years ago a review of the performance and operating experience on the machines involved in this plan resulted in the design and trial of a system using a direct-connected exciter with amplidyne control for excitation of a large synchronous condenser. Following this, four similar installations were provided. Thus there has been obtained a wide variety of experience with excitation systems and associated equipment. It is the purpose of this paper to recount these developments, describe typical installations, and discuss the operating results obtained with them.