Evaluation of Power-Ratings for Active Series Filters under Unbalanced Conditions for a Three Phase - Four Wire System

The optimal power rating of a series active filter is important not only in design of compensator for a specific application, but also in determining the best compensation strategy for a specific application. This paper focus mainly on the confront of the power rating of a combined system consisting of two small rating series active filters and a shunt passive filter generally designed for balanced condition, and the power rating required when it´s working under unbalanced conditions. This paper highlights the overload imposed to the active series filters for two different degree of imbalance showing that even if the overloaded doesn´t exist the system wont be free of harmonic pollution, exceeding the IEEE 519 recommendations