A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering, School of Engineering and Technology

Thesis (M.Eng.) - Asian Institute of Technology, 1990

Many methods are suggested to perform optimization of reservoir systems. But these optimization techniques are not able to analyze complicated reservoir system due to the curse of dimensionality associated in formulation of the mathematical model. This study is focused on deriving an operating policy by heuristic approach for a series reservoir system and a parallel reservoir system both consisting of two reservoirs each. Three heuristic models with different approaches are tested to find the best approach. In the model one two state variable deterministic dynamic programming (DDP) model with objective function of maximizing total power generation is solved for 12 months of average inflows and irrigation demands to obtain operating rules for each reservoir and they are used in a simulation model and improved until an acceptable result is reached. In the second model DDP is applied to entire time horizon of 32 years and also sequentially to the system to find a firm energy target and then the systems are simulated by supplying this targets and thereby improving them to a maximum possible without system failures. The third model is based on two thumb rules. The series system is operated by satisfying demands from the downstream reservoir while parallel system is operated by maintaining its ratio of empty space of a reservoir to the respective expected inflow, constant. Model 1 consumes the highest amount of computer time but the gain on the total power production compared to the third model is marginal. The second model gives better answers in much less computer time. Third model gives the best results with lesser computer time for both systems. It proves that the above thumb rule in acceptable in operation of the parallel reservoir system for power generation. And also the rule can be applied to series reservoir system with power and irrigation demands in such a way that the wastage of water form the system compared to irrigation is minimal.