A Decision Support System to Optimize the Operation of Hydro Generating Systems

We describe a decision support system that has been developed to determine the optimal generation schedules for hydroelectric systems. The system has been developed for use in real time and short-term system operations planning to determine the optimal hydroelectric unit generation schedule for plants with multiple units and complex hydraulic configurations. The system is one of the tools that are currently in the implementation phase at BC Hydro in British Columbia, Canada. The system consists of two main modules: the Short-term optimization modules (STOM and REOM) and the Dynamic Unit Commitment and Loading (DUCL) module. The STOM module is formulated as a large-scale linear programming algorithm and is solved using an advanced commercially available algebraic modeling language and a linear programming package. The REOM module is an adaptation of the STOM module to address the special case of maximizing the import capability of the hydro system. The DUCL module is formulated and solved using a hybrid system consisting of three algorithms. First, an expert system is used to eliminate infeasible and undesirable solutions. Second, dynamic programming algorithm is used to solve the optimal static unit commitment problem for a given plant loading, feasible unit commitments, and current hydraulic configurations. Third, the dynamic unit commitment and loading problem, which is formulated and solved as a large-scale mixed integer programming. The system has been designed and implemented to be user-friendly, flexible, dynamic, and a fast real time operational tool that accurately portrays the complex nature of the optimization problem. The fast run time of the methodology adopted allows it to be used for scheduling hydro units for the energy and the capacity markets in real-time and in short-term operations. The application of the method is demonstrated for four hydro plants for a 24-time-step study.