Investigation and recommendation on allowable operating duration of large-sized turbine-generator unit under abnormal frequency

(整期优先)网络出版时间:1992-03-13
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1.IntroductionWiththeincreasingofturbo-generator(TG)capacity,thelimi-tationontheabnormalfrequencyoperationisgrowingmorerestric-tive.InordertoensurethesafetyoperationofcertainTGunit,splitingdevicewhichisolatesthegeneratingunitfromthesystemisem-ployedwhenthesystemfrequencyisdeclinedtoacertainextent.However,duringthedegradationoffrequency,toisolatethelarge-sizedTGunitfromthepowersystemwillcausethesystemfre-quencytofurtherdecline.Hence,howtousethelowfrequencysplit-tingprotectionproperlyandhowtocoordinatetheoperationofunderfrequencyloadshedding(UFLS)withunderfrequencygeneratorsplitting(UFGS)aresignificantforsecuringthesafetyoperationof