Comparison of model based feed-forward control strategies for impounded rivers

The automatic management of barrage controlled river segments tries to ensure easy and safe navigation and at the same time suppress large water discharge variations. The predominant local PI based control solution used in Moselle river barrages can only guarantee a steady water level at the cost of possibly amplifying inflow disturbances. To balance these contradicting goals, a model predictive controller (MPC) based feed-forward control method is proposed to retrofit the already established local PI-control. The propsed method does not require feedback from the plant, eliminating unwanted interactions with already installed controllers. To achieve real time operation on industrial control hardware, the MPC utilizes simplified river models. Two approaches are compared in this paper: Fully linearized and discretized Saint-Venant equations and an analytical approximate solution of the Hayami equations are used as discharge prediction models for the MPC. The satisfying performance of the proposed approaches is demonstrated using a verified numerical simulation model and is compared to the performance of the existing PI control solution.