Maximum-Slew-Rate Control for Hydrogenerators

Traditionally, speed control of hydrogenerators has been implemented by analog proportional-plus-integral control of speed error. With digital controllers, nonlinear, adaptive control strategies may be implemented to achieve improved systems response. This paper develops a control scheme which responds to perturbations by moving wicket gates at their maximum slew rate. For a simulated 10 percent load rejection, the new controller reduced settling time by over 50 percent as compared to the equal-root-case PI controller. This was achieved while maintaining the same peak overshoot and keeping pressure within design limits. The deadbeat nature of the transient response promises decreased wear on mechanical components while substantially improving overall performance of hydrogenerators.