Unstable frequency oscillations in a slow-response reheat-turbine generator

This paper shows that governor rate limits may result in slow response that interacts with that of a reheat turbine to create unstable frequency oscillations. The origin of these oscillations is explained with a linear analogue, while nonlinear simulation shows that the oscillations evolve into a limit cycle due to gate limits. A control scheme to stabilize the frequency oscillations through control of the intercept valve is developed and tested in the paper.