Load Frequency Control of an Isolated Small-Hydro Power Plant With Reduced Dump Load

In this paper, a novel technique for load frequency control of an isolated small-hydro plant is presented. In general, the frequency is controlled by using a dump load, whose rating is equal to the rated power output of the plant. The new scheme proposed reduces the size of the dump load by controlling input power of the hydro power plant using on/off controls. The water flowing through the penstock is rerouted in smaller pipes, two or three fitted with motor operated valves. The opening or closing of the valves is achieved by on/off controls. The on/off control linearly raises or lowers the generation. A generalized transfer function model for the system is developed with an on/off control logic. Finally, the transient performance of the system is compared for the two-pipe case (50% dump load) and the three-pipe case (30% dump load)