Solving the unit commitment problem of hydropower plants via Lagrangian Relaxation and Sequential Quadratic Programming



Document title: Solving the unit commitment problem of hydropower plants via Lagrangian Relaxation and Sequential Quadratic Programming
Journal: Computational & applied mathematics
Database: PERIÓDICA
System number: 000269388
ISSN: 1807-0302
Authors: 1

2
Institutions: 1Laboratorio de Planejamento de Sistemas de Energia Eletrica, Florianopolis, Santa Catarina. Brasil
2Instituto de Matematica Pura e Aplicada, Rio de Janeiro. Brasil
Year:
Season: Sep-Dic
Volumen: 24
Number: 3
Pages: 317-342
Country: Brasil
Language: Inglés
Document type: Artículo
Approach: Analítico, descriptivo
English abstract We consider the optimal scheduling of hydropower plants in a hydrothermal interconnected system. This problem, of outmost importance for large-scale power systems with a high proportion of hydraulic generation, requires a detailed description of the so-called hydro unit production function. In our model, we relate the amount of generated hydropower to nonlinear tailrace levels; we also take into account hydraulic losses, turbine-generator efficiencies, as well as multiple 0-1 states associated with forbidden operation zones. Forbidden zones are crucial to avoid nasty phenomena such as mechanical vibrations in the turbine, cavitation, and low efficiency levels. The minimization of operating costs subject to such detailed constraints results in a large-scale mixed-integer nonlinear programming problem. By means of Lagrangian Relaxation, the original problem is split into a sequence of smaller and easy-to-solve subproblems, coordinated by a dual master program. In order to deal better with the combinatorial aspect introduced by the forbidden zones, we derive three different decomposition strategies, applicable to various configurations of hydro plants (with few or many units, which can be identical or different). We use a Sequential Quadratic Programming algorithm to solve nonlinear subproblems. We assess our approach on a real-life hydroelectric configuration extracted from the south sub region of the Brazilian hydrothermal power system
Disciplines: Matemáticas,
Ciencias de la computación,
Ingeniería
Keyword: Matemáticas aplicadas,
Ingeniería de control,
Sistemas hidrotermales,
Plantas hidroeléctricas,
Relajación Lagrangiana,
Programación cuadrática secuencial
Keyword: Mathematics,
Computer science,
Engineering,
Applied mathematics,
Control engineering,
Hydrothermal systems,
Hydropower plants,
Lagrangian relaxation,
Sequential quadratic programming
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