Selected issues of cable link designing in HVAC and HVDC submarine power grids

Submarine (offshore) HVAC and HVDC cable power grids will play bigger and bigger role in the nearest future. In particular it will be connected with development of offshore wind farms and establishment of submarine transmission interconnections between the various national power systems. It results in necessity to elaborate proper procedures of designing of cable links (lines) which are part of HVAC and HVDC submarine power grids. Concept of offshore cable power grids in the context of introducing (injecting) of power generated in offshore wind farms to on-shore power grids and intersystem power exchange have been described in the paper. Submarine cable link as an element of submarine power grid have been described. Examples of existing submarine cable links and the ones that are being designed, as well as examples of offshore power grids have been given. Then technical characteristic of HVAC and HVDC submarine power cables have been presented. In the further part of the paper general power system requirements concerning cooperation of submarine cable link and on-shore power grid have been formulated. The main part of the paper concerns designing process of HVAC and HVDC submarine cable links. General and detailed rules of designing of both types of submarine cable links, considering difficulties well known from practice, have been described. At the end of the paper summary and final conclusions have been presented.