Frequency fuzzy anti-islanding for grid-connected and islanding operation in distributed generation systems - Aguiar, Cassius Rossi de; Bastos, Renan Fernandes; Gonçalves, Amílcar Flamarion Querubini; Neves, Rodolpho Vilela Alves; Reis, Giann Braune; Machado, Ricardo Quadros (IET Power Electronics, 2015)