Ferramenta para avaliação da energia firme baseada em técnica de pontos interiores

Abstract

The energy sector planning is fundamental to assure the energy supply at the smallest costs and risks and with the smallest socioeconomic and environmental impacts for the society. These factors as well as the aspects complexity involved in the industry operation of the electrical energy production explain the importance of the energy sector planning. Nowadays, the Brazilian electrical system is operated centralized by regulators agents that acts with great institutional power on the system’s variables through decisions that brings impacts and strongly influence the future of the systems. The fact of the Brazilian system predominantly being hydroelectric does those decisions, in most of the time, to be taken in an uncertain environment and then requires systematic processes of decision support, especially above the future perspectives regarding the energy supply risks. In this context, the firm energy, defined as the maximum continuous capacity of energy production, without the occurrence of energy deficits, influence directly the remuneration of the hydroelectric power stations and the electric power sales contracts because it is used in the evaluation of the assured energy, that represents the energy generation ballast of these plants in Brazil. Today, the firm energy evaluation of each hydroelectric power station of the Brazilian electrical system is accomplished through simulation models, in particular, the MSUI model, developed by Eletrobr´as and the SUISHI-O model, developed by CEPEL. The power stations topology is respected and, through heuristic rules, is simulated its operation, considering the historical flow series since January of 1931. This work has as objective the development of a computacional tool destined to the firm energy evaluation of the hydroelectric power stations. For this, a solution is proposed, through a single nonlinear programming problem, with the representation of the nonlinearities inherent to the hydroelectric power stations productivity and the individualized reservoirs representation together with the historical flow series since January of 1931. The solution of the nonlinear optimization problem is obtained through Primal-Dual Interior Point Method. The proposed methodology was implemented in computational language C++, allowing to apply the firm energy evaluation to the Brazilian Interconnected National System. A study case will be presented extending the Brazilian Interconnected National System, resulting in a problem with more than 400 thousand variables, in wich it will be observed the importance to solve the problem considering the nonlinearities in a unique optimization problem. These results were compared to the obtained ones with the linear model of the firm energy evaluation. Additional results with the entrance of new power stations in the system (Estreito Tocantins and Peixe Angical) are evaluated to validate the methodology appliance to real systems. The obtained results shows that the proposed methodology is promising. Additionally, the developed software is a tool capable to receive improvements and modifications for incorporation of several other functionalities related to the planning and operation of electrical power systems.