Excitation ControltoImprove Powerline Stability

The influence ofgenerator voltage regulators upon powerline stability isclosely scrutinized byanalog techniques. Con- trary tocommonconcepts, itisshownthathigh-speed control of excitation tomaintain constant terminal voltage actually hampers rather thanaidsdamping andpowerline stability. Itisfurther shown thatdamping andstability aregreatly improved bysupplementing excitation control withaspecially derived function offrequency de- viation. Results ofthestudies areverified inactual performance ob- tained infield tests.