The Brazilian interconnected power system consists of a linked network of over 150 medium and large reservoirs, and a large set of small hydropower, thermal, and wind power plants. Hydropower has been the predominant source of electrical energy supply in Brazil, with significant increasing participation share of run-of-river hydropower, and thermal and wind power plants. In this paper we modify the HIDROTERM, a nonlinear programming optimization model previously developed for planning the operation of the Brazilian hydrothermal system. First, we modify the storage constraints at the end of the planning horizon based not only on individual storage at each reservoir, but also consider the stored energy in each subsystem. Additionally, we penalize unnecessary spills and reward storage savings over the minimum requirements. The first modification increases the feasible region in the decision space, while the second modification is directly included in the objective function. These modifications were tested with different hydrological scenarios and initial conditions of the hydropower system. The modifications have resulted several benefits, including a greater flexibility to storage water in the multiple reservoir system, reduction of infeasibilities under more severe drought scenarios, increased productivity in some cascade reservoir systems with reduction in thermal dispatch and operational costs, and increased water savings at the end of the planning horizon.
Artigo retirado do site: https://ascelibrary.org/doi/abs/10.1061/9780784482957.019