Governor control for Kakabeka Falls Generating Station

Abstract

This thesis examines a specific problem of governor control on a set of hydroelectric turbines that suffer from severe wicket gate leakage. Linear modeling and the steady state behavior of each turbine is investigated and used to determine the best means of speed control. Findings show that a secondary water control device may be used with the wicket gates to alleviate the effects o f leakage while the generator is disconnected from the transmission system. The control method results in two distinct modes of turbine operation, with each having significantly different dynamic characteristics. A digital speed droop governor scheme is considered in a gain scheduling arrangement to account for the two operating modes. The stability boundaries of the governor parameters are investigated, and an output feedback cost minimization algorithm is used for obtaining controller gains. An outline of the software used to implement the governor on an industrial programmable controller is presented, and the experimental performance for the turbines is compared to the theoretically developed model.