Intelligent overcurrent protection during Ferroresonance in smart distribution grid

摘要

Smart grid includes utility system and renewable Generations like wind turbine and solar panel. It stablishes bidirectional power flow and communication among utility, Dispersed Generations (DG) and consumers. In this paper, impact of ferroresonance in utility system is analyzed on electrical and mechanical parameters of DFIG (Doubly-Fed Induction Generator) and behavior of directional overcurrent relay in wind farm by PSCAD/EMTDC software. Smart grid requires a self-healing protection; hence, an intelligent overcurrent relay based on wavelet transform, neural network and time domain analysis of ferroresonance is proposed for overcurrent relay. The relay is able to comply with smart grid protection strategies. It distinguishes ferroresonance from other phenomena, which cause deviation of electrical parameters. Protection strategy determines behavior of the relay via the algorithm. It makes a suitable decision in ferroresonance to change setting parameters and direction of operation to increase reliability and availability in smart grid. The relay is also able to predict ferroresonant states in the network to indulge smart grid requirements.