The benefits of utilizing energy exchange between the Norwegian hydroelectric power system and the thermal power systems in Europe make it interesting to establish new HVDC sea cable interconnections. Providing the required licenses are issued by the national authorities involved, several new HVDC links may be established from the southern part of Norway to the continent each having a cable length of approximately 550 km. A total power of 3000 MW or more can then be exchanged through the HVDC links including the existing Skagerrak interconnection. It is planned to transmit a maximum power of 600 MW or even 800 MW, by each new HVDC link at a DC voltage of 500 kV assuming that progress in cable technology allows this voltage level in the coming years. A feasibility study with detailed modelling of all HVDC interconnections, the AC system of Southern Norway and relevant parts of the UCPTE system has been carried out. Especially the close electrical proximity between the converter stations in Norway (the distance between the converter stations is 40-60 km) requires detailed studies using digital simulation. In the following the advantages of energy interchange, technical aspects and the main results of the system dynamic study are discussed.