Voltage unbalace numerical evaluation and minimization:estimation by incremental sensitivity analysis and analytical solutions / Avaliação e minimização numérica do desequilíbrio de tensão : estimativa por análise de sensibilidade incremental e soluções analíticas

AUTOR(ES)
DATA DE PUBLICAÇÃO

2007

RESUMO

Voltage unbalance is one of the parameters analysed in power quality studies, representing the difference between the magnitudes of the voltages of a tri-phase electrical system, and the phase shift between these. It is desirable to have sinusoidal voltages with identical magnitudes and 120 electrical degrees phase shift between them, but in practice, there is always a deviation from this ideal case, due to characteristics such as bad distribution of single-phase loads and the presence of transformers, transmission lines e capacitor banks with assembly differences between phases. These differences cause losses both to the consumer and to the energy supplier, such as reduced efficiency of tri-phase induction motors. In order to determine the influence of the networks parameters (magnitudes and phase shifts of the three phases) on voltage unbalance, and the values required to reduce or even eliminate it, the present work develops and presents two analysis methods. The influence of each parameter is determined through incremental sensitivity calculations, and the changes needed for reduction are calculated by analytical solutions. The quantification index considered is the symmetrical components method. All methods developed were implemented in software, and their validity was tested for a series of unbalance situations.

ASSUNTO(S)

engenharia eletrica qualidade de energia redução de desequilibrio de tensão desequilibrio de tensão análise de desequilibrio de tensão

ACESSO AO ARTIGO

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