An intelligent algorithm for Negative Sequence Directional Element of DFIG during Ferroresonance in smart grid

Abstract

Smart grid includes utility system and Distributed renewable Generations like wind turbine and solar panel. It provides bidirectional power flow and communication among utility, Distributed Generations (DG) and consumers. In this paper, impact of ferroresonance in utility system is analyzed on DFIG (Doubly-Fed Induction Generator) and Negative Sequence Directional Element (NSDE) in wind farm by PSCAD/EMTDC software. As smart grid requires a self-healing protection, an intelligent algorithm based on wavelet transform, neural network and time domain analysis of ferroresonance is proposed for NSDE to distinguish ferroresonant states. The algorithm is able to comply with smart grid protection strategies. It distinguishes ferroresonance from other transients and determines ferroresonance of different types. Then it receives the commands based on protection strategy to make a suitable decision in ferroresonance to increase reliability and availability in smart grid. In comply with smart grid requirements; the algorithm is also able to predict ferroresonant states in the network.