Robust H∞ control for hydro-turbine governing system of hydropower plant with super long headrace tunnel

Abstract

This paper investigates the robust H∞ control for hydro-turbine governing system (HTGS) of hydropower plant with super long headrace tunnel (SLHT). Firstly, the state equation of HTGS with SLHT is derived to describe the nonlinear performance of HTGS without control. Then, the robust H∞ control strategy for HTGS with SLHT is designed based on the exact linearization of HTGS with SLHT and construction of nominal output function (NOF). Finally, the regulation quality of HTGS with SLHT under robust H∞ control strategy is investigated. The applicability and robustness of robust H∞ control strategy for HTGS with SLHT are studied. The results show that the optimal robust H∞ control strategy for HTGS with SLHT is composed of the optimal gain variable, NOF and Lie derivative of NOF. The NOF is the linear combination of the four state variables of HTGS. Under robust H∞ control strategy, the dynamic response of HTGS with SLHT is rapid and sensitive. The regulation quality of HTGS with SLHT under robust H∞ control strategy is much better than that under Proportional - Integral - Derivative (PID) control strategy. The water level oscillation in surge tank can be effectively regulated and restrained by the robust H∞ control strategy. The robust H∞ control strategy has an excellent applicability for HTGS with SLHT. The robustness of robust H∞ control strategy for HTGS with SLHT is much better than that of PID control strategy for HTGS with SLHT.