Progress in the development and testing of OTEC riser cables

Abstract

Developmental testing and analysis of OTEC riser cables has been undertaken. Two full-size riser cables have been manufactured and tested, one using cross-linked polyethylene (XLPE) insulation, the other using self-contained, oil-filled (SCOF) paper insulation. These cables and their components have been subjected to testing simulating handling and installation prior to OTEC service, as well as electrical and mechanical loads predicted in service. Results to date indicate that the XLPE cable has significant potential for use as an OTEC riser cable. The XLPE cable has performed well in mechanical and electrical testing. Results for the SCOF cable are mixed. The SCOF cable tested collapses due to pressure at depths typical of OTEC service and slippage occurs within the insulation resulting in early electrical failure of SCOF samples during combined electrical and mechanical tests. The implications of these findings for cable development and for the selection of a preferred candidate OTEC riser cable are discussed.