Predictive feedforward control for a hydroelectric plant

In this brief, it is shown that predictive feedforward control can be used to help a hydroelectric plant achieve its target for delivered power while operating in grid (power system) frequency control mode. Due to the fundamental limitation on how fast the water in the supply tunnel can be accelerated by gravity, a hydraulic turbine is always subject to some delay between opening or closing its guide vane and the consequent change in power. Here, it is proposed that the effect of this delay can be alleviated by predicting 3-4 s ahead what power will be required, based on grid frequency measurements, and using this as a feedforward signal to supplement the normal PID feedback controller. Results are presented to show the improved accuracy of power delivery achieved with this approach.