A non-linear model based feed forward flatness control approach to speed governor systems of hydropower plants

Abstract

A NON-LINEAR MODEL BASED FEED FORWARD FLATNESS CONTROL APPROACH TO SPEED GOVERNOR SYSTEMS OF HYDROPOWER PLANTS İlhan Koşalay, Derya ÖzkayaProfessional paper This study is a part of a refurbishment project, which renews the hydro-mechanical speed governor of a hydroelectric power plant (HEPP) with a new digital one. Based on the previous study of the project, which covers the validation of the HEPP model, the simulation studies implemented in Matlab/Simulink environment are conducted to design the best controller philosophy for the digital speed governor controller. In order to be able to give satisfactory response to the load frequency control of the power system, the speed governor should respond to the set point changes as quickly as possible within the safe margins. In order to compensate unsatisfactory performance indices of conventional proportional-integral (PI) controller, a new controller based on the differential flatness theory is designed. The new controller is constructed by adding on a flatness-based feed forward part to the existing PI feedback controller, which results in improved performance compared to the conventional PI controller. Keywords: flatness-based controller; hydroelectric power plant modelling; load frequency control; speed governor Pristup reguliranju ravnomjernosti s unaprijednom spregom sustava regulatora brzine hidroelektrana zasnovan na nelinearnom modeluStručni članak Ovo istraživanje je dio projekta sanacije kojim se hidro-mehanički regulator brzine hidroelektrane (HEPP) zamjenjuje s novim, digitalnim. Na temelju ranijeg istraživanja procjene HEPP modela, simulacijska istraživanja u Matlab/Simulink okruženju provedena su u svrhu razvijanja najbolje filozofije za proizvodnju digitalnog regulatora brzine. Kako bi se moglo ponuditi odgovarajuće rješenje za reguliranje učestalosti punjenja energetskog sustava, regulator brzine bi u okviru dopuštenih granica trebao što brže reagirati na zadane promjene. U svrhu kompenzacije pokazatelja nezadovoljavajuće performanse uobičajenog proporcionalno-integralnog (PI) regulatora, konstruiran je novi regulator zasnovan na teoriji diferencijalne ravnomjernosti. Novi je regulator konstruiran dodavanjem postojećem PI regulatoru povratne sprege na ravnomjernosti zasnovan dio unaprijedne sprege. Rezultat je bolji rad nego s konvencionalnim PI regulatorom.Ključne riječi: modeliranje hidroelektrane; regulator brzine; regulator brzine punjenja; regulator zasnovan na ravnomjernosti