Impacto da proteção do tipo crowbar dos aerogeradores de indução duplamente excitados nos sistemas de proteção de redes de distribuição

Abstract

The continued incorporation of distributed generation from renewable sources to electricity networks in the world, has contributed positively in the energy supply, energy efficiency and reduction of polluting gases. Nevertheless, new challenges related to the variations in power quality, system stability, short circuit levels, among others, continue to be research. The Brazil has added in recent years an important amount of gigawatts to networks through the connection of large wind farms. In addition, recent possibilities for consumers to make small generators and exchange energy in the distribution network aims to connect another quantity of gigawatts. In this context, this work presents the analysis of the impact of Crowbar protection of double feed induction generator (DFIG) on protection systems used in radial distribution networks to evaluate its influence on the coordination of overcurrent protection functions when there are faults in the network. To reach this goal, assessments of contributions to short-circuit currents of DFIG connected to the grid during disturbance, was simulated in DIGSILENT Power Factory 14.1 software where two cases where considered. The first includes the non-inclusion of crowbar protection and the second considers the inclusion of this protection during a network disturbance. The strategy implemented on crowbar protection proposed the series resistance insertion in the rotor circuit when thresholds velocity, current in the rotor and voltage at the connection point, are Exceeded. The results provide relevant short-circuit levels information that from now on must be considered during previous DFIG connection studies due to the importance they represent to coordinate overcurrent protection function under dynamic and steady state conditions.