This paper describes the development and application of LINGO model to the optimal operation of a multi-reservoir system. The original four-reservoir problem (Larson, 1968) with linear objective function and a modified problem with nonlinear objective function have been solved using LINGO model. To evaluate the performance of LINGO model, both the problems have also been solved using discrete differential dynamic programming (DDDP). Performance of LINGO and DDDP-based optimisation models was evaluated on the basis of the objective function values achieved, the execution time required and the optimal state trajectories produced. Optimal storage trajectories obtained from both the models have been presented. The LINGO model was found to be superior to DDDP model in terms of execution time, although optimal state trajectories produced by each model are identical. A distinct practical contribution of the present research is that a LINGO model free from dimensionality problems has been developed for the optimisation of multi reservoir systems operations. An added advantage of the LINGO model is that it is transportable with minimum changes to any reservoir system.
Keywords: LINGO, dynamic, programming, reservoir, optimisation