A FUZZY NUMBER BASED METHODOLOGY FOR HARMONIC LOAD-FLOW CALCULATION, CONSIDERING UNCERTAINTIES

摘要

Nonlinear devices are being increasingly used in power systems and, as a consequence, harmonic distortion is a continuously growing phenomenon. Since linear and nonlinear loads are usually uncertain variables that, in addition, vary constantly, probabilistic methods for harmonic load-flow calculation have been developed to quantify the resulting random harmonic voltages. More recently, a possibilistic harmonic load-flow based on fuzzy sets theory has been proposed with the same objective. Although the possibilistic approach seems better suited to deal with the kind of uncertainty usually found in practice, the Classic Fuzzy Solution on which this methodology relies exhibits some drawbacks. This paper proposes a possibilistic harmonic load-flow based on the Marginal Joint Solution, which overcomes two major limitations of the Classic Fuzzy Solution approach: the lack of fuzzy linear loads models, and the over-and underestimation of the harmonic voltages.