Compensadores série de baixa tensão: topologias, técnicas de projeto e viabilidade econômica

Abstract

Fron an economic viewpoint, voltage sags are the worst power quality phenomena for industrial power plants. In order to eliminate their related problems or minimize their effects, a considerable number of solutions has been proposed and implemented. Among them, it can be pointed out the power conditioning devices, installed between the grid and sensitive load. At this scenario, series compensators have considerable importance due to their low cost and effectiveness.The majority of the manufactures of series compensators promote its products by means of their high-level voltage sag support, in addition to other benefits like voltage regulation and compensation of harmonic distortions. However, there is no research pointing out economicalcosts due to these features. This work demonstrates that there are considerable economical and dimensional cost differences between devices designed to operate just for short periods (voltage sag support)and those designed to operate continuously. In order to get this results, special design techniques for power devices were developed, considering their dynamic electrical and thermal behavior. These techniques were important to obtain appropriated designs, avoidingover dimensioning. Furthermore their majority is applicable for design of any equipment that uses CC-CA converters, despite their duty-cycles or load profile. In addition, the most appropriate topologies for low voltage application are investigated and proposed. Complete series compensator designs, for devices with different features, are shown and costs comparisons done. The most appropriate solution for power quality problems involves an economic issue: it is necessary to minimize the sum of total financial losses and acquirement and maintenancesolutions costs. Aiming the appropriated solution, a detailed study is necessary. This study involves knowledge of the characteristics of the quality events, load behavior and economical losses associated to their failure and about the several existent solutions, including itsadvantages and disadvantages. Through this study, the global objective of present methodologies for appropriated solution was reached as well is evidenced the applicability and benefits of short period operation series compensator.