Active power losses in the collecting network of distributed renewable energy sources have a significant ratio in the cost of produced electricity, especially in offshore systems. As a consequence an extension of the DC technology to the collecting medium voltage network of the distributed renewable energy sources is an obvious option. This option has the potential of improving the efficiency and, as a consequence, to reduce energy production cost. In the paper is analysed the off-shore used DC technologies state of art with a special accent on high power level DC electronic converters. The considerations related to establish of the DC “Dual Active Bridge” analytical model are analysed. This structure results as optimal in order to reduce the losses in the DC collecting medium voltage network.