transition from isochronous control to droop control in the short term most electrical systems will maintain a constant frequency if power levels are maintained hence the speed and load control 34 includes a sample and hold device 70 and a comparator 72 which operate cooperatively to adjust the level of the speed reference signal 56 to maintain a constant output power while the power feedback signal is gradually introduced to the controller 50 at the instant a transition from isochronous to droop mode is initiated the sample and hold device 70 records the level of the power feedback signal 60 the sampled signal and the power feedback signal are then continuously compared by the comparator 72 which is connected to a reference control device 74 the level of the speed reference signal 56 is increased or decreased by the reference control device 74 as necessary to maintain a constant power output level on the turbine this will in turn minimize fluctuations in signal frequency during the transition period at the conclusion of the transition a booster generating unit that was formerly operating in the droop mode will then be operating in the isochronous mode assuring a constant frequency hence the present invention provides means for gradually switching a combustion turbine speed and load control between the isochronous and droop modes of control ramping the power feedback signal 60 into and out of the.