Estratégia de controle e proteção das turbinas eólicas com geradores duplamente alimentados para suportabilidade a afundamentos de tensão.

Abstract

The continuous integration of distributed generation into the world’s electricity networks, from renewable sources, has contributed positively to the generation of energy. Among the renewable sources, wind energy has stood out for being promising due to its economic viability and rapid technological development. To satisfy the increasingly stringent requirements without reducing the economic advantage of wind power systems, new control and protection strategies for sags are being studied. For the wind system, crowbar with constant resistance is a popular approach that protects aerogenerators and improves the low voltage path. However, the system’s responses depend on the degree of voltage drop, as the constant crowbar resistance may be under or overestimated, resulting in damage to the machine. Therefore, the crowbar resistance is an important parameter and should be selected taking into consideration the limits of rotor overcurrent and bus overvoltage. Thus, this Thesis presents a control strategy that allows regulating the active and reactive powers of the induction generator doubly fed in a stable and independent way, and an adaptive control protection system for selecting the crowbar resistance due to the degree of sag. An analytical expression for the resistance is presented together with the control strategy. The effectiveness of the proposed method is validated through theoretical analysis and simulations in Matlab/Simulinkr.