Development of 500 kV DC PPLP-insulated oil-filled submarine cable

This paper outlines the development of a 500 kV DC oil-filled submarine cable capable of transmitting 2800 MW with /spl plusmn/500 kV 2800 A bipole system. Polypropylene laminated paper (PPLP) was employed as the insulation material, which is the world's first application to DC cables. The conductor size is 3000 mm/sup 2/, which is the largest size for submarine cables ever put into practical use. Through various fundamental and prototype tests, the cable proved to have excellent electrical characteristics for DC voltage as well as transient overvoltage. The cable and accessories are undergoing a long-term accelerated aging test as the final confirmation of their reliability and stability.