Aggregation‐Disaggregation Approach to multireservoir operation

Abstract

A group of optimization models for the real-time operation of a hydropower system of reservoirs is presented in this paper. The dimensionality problems usually found in dynamic programming formulations are solved by a space-time aggregation/disaggregation procedure that combines stochastic dynamic programming and linear programming techniques. The reservoirs in a hydropower system are aggregated in power units rather than in water units, and an optimal operating policy for the equivalent aggregated reservoir is found in the first part of this work. The objective function in this first part is to minimize the total cost or energy production for a hydrothermal system. The aggregated policy obtained is used in the real-time operation of the system to determine the recommended daily releases and power production from each reservoir of the system. The proposed methodology is applied to a case study, the Lower Caroni system in Venezuela, which is composed of four reservoirs in series and a total installed capacity of 17,000 MW, with satisfactory results.