Smart5Grid Solutions for enhanced TSO grid observability and manageability in massive RES penetration environment [version 2; peer review: 1 approved, 2 approved with reservations,... oleh Ioannis Chochliouros, Michalis Rantopoulos, Vasiliki Vlahodimitropoulou, Ralitsa Rumenova, Krassimir Vlachkov, Daniel Shangov, Atanas Velkov, Georgi Hristov, Nicola Cadenelli, Angelos Antonopoulos, Dimitrios Brodimas, Nikolaos Tzanis