Doctoral Thesis
DOI
10.11606/T.18.2017.tde-06062017-072758
Document
Author
Full name
Fillipe Matos de Vasconcelos
Institute/School/College
Knowledge Area
Date of Defense
Published
São Carlos, 2017
Supervisor
Committee
Costa, Geraldo Roberto Martins da (President)
Ohishi, Takaaki
Oleskovicz, Mario
Pereira Junior, Benvindo Rodrigues
Sousa, Thales
Title in Portuguese
Uma abordagem Lagrangiana na otimização Volt/VAr em redes de distribuição
Keywords in Portuguese
Bancos de capacitores
Função senoidal de penalização
Operação de sistemas de distribuição de energia
Programação não linear
Transformadores com comutação de tap sob carga
Variáveis contínuas e discretas
Abstract in Portuguese
Title in English
A Lagrangian approach in the Volt/VAr optimization in distribution networks
Keywords in English
Capacitor banks
Continuous and discrete variables
Nonlinear programming
Operation of power distribution systems
Sinusoidal penalty function
Abstract in English
This work proposes a new model and a new approach for solving the Volt / VAr optimization problem in distribution systems. The Volt/VAr optimization consists, basically, to determine the settings of the control variables of switched capacitor banks, on-load tap changer transformers and voltage regulators, in order to satisfy both the load and operational constraints, to a given operational objective. The problem is formulated as a nonlinear programming problem, multiperiod, and with continuous and discrete variables. Nonlinear programming algorithms were used in order to take advantage of the highly sparse matrices built along the solution method. The discrete variables are treated as continuous along the solution method by means of the use of sinusoidal functions that penalize the original objective function while the control variables do not converge to any of the predefined discrete points in its domain. The multiperiod, or dynamic, characteristic of the problem, however, refers to the use of a constraint that relates the settings of the control variables for successive time intervals that limits the control devices switching operations number for a period of 24-hours. The study is based, methodologically, on Primal-Dual Logarithmic Barrier method. To demonstrate the effectiveness of the proposed model and the robustness of this approach, the data were obtained from theoretical literature surveys, and tests were performed on test-systems of 10, 69 and 135 buses, and in a 442 buses located in the Northwest of the United Kingdom. The computational implementation was accomplished in the softwares MATLAB, AIMMS and GAMS, using the IPOPT solver as solution method. The results have shown the approach for solving nonlinear programming problems is effective to appropriate cope with all the variables presented in Volt/VAr optimization problems.