Ballestin-Fuertes, Javier Sanz-Osorio, Jose F. Muñoz-Cruzado-Alba, Jesus Laporta Puyal, Erika Leiva, Javier Rodriguez Rivero, Jacob Four-Legs D-STATCOM for Current Balancing in Low-Voltage Distribution Grids IEEE Access 10.1109/ACCESS.2021.3138827 2022 2022