Handling state dependent nonlinear tunnel flows in short-term hydropower scheduling

Abstract

The paper proposes a method to handle state dependent nonlinearities in a linear programming scheme. Although the angle of the article is focusing on application of the method to short-term hydropower scheduling, the technique is general and can be used on other problems as well. The approach is based on successive linear programming for dealing with both the state dependency and the nonlinearity. A scheme for handling tight hydraulic coupling with relative short time constants and pressure balance is demonstrated in the paper. After the introduction we will give a brief description of the basic principles in successive linear programming. Then the details of the techniques used to deal with state dependent nonlinear flow is described and tied to specific topologies. Finally it will be shown how the use of simulation can give faster convergence.