Avaliação do impacto de plantas eólicas interfaceadas por conversores em funções convencionais de proteção de linhas de transmissão

Abstract

Wind energy has been shown to be increasingly important in the energy scenario of modern electrical systems, contributing with a relevant portion of the total installed capacity in Brazil and in several other countries worldwide. The topologies of wind generation units are diverse and, among those that have aroused the concern of researchers in the electric sector about their influence on protection schemes performance, DFIG (Type III) and Full-Converter (Type IV) are highlighted, which use converters to grid interface of generating units. In this context, considering the increasing integration of generating units with such topologies in the electrical power system, clarifications about the impact of these systems on protection functions have attracted the interest of utilities and researchers. Therefore, this work explores concepts related to the operation and composition of the main types of wind generation, carrying out studies by means of computer simulations, with an EMTP type software, which aim to explore the main differences between the contributions of wind and conventional generations being the network subjected to contingencies. Considering the results obtained from the simulations, behavior of electrical quantities and functions typically employed in the transmission lines protection are analyzed, focusing on: 1) Short circuit level, since it can affect all protection functions that depend on current magnitude analysis; 2) Sequence components, since such components are used in the operation of protection functions, faulted phase selection algorithms and directional elements; 3) Distance protection function, since it is one of the most used functionalities in transmission systems, either as main or backup protection. Finally, the conclusions obtained are detailed from the studies, highlighting the problems encountered with regard to the operation of conventional protection systems due to the impacts related to DFIG and Full-Converter topologies.