Power Cables in the Twenty-First Century
Abstract:This paper presents a variety of viewpoints from engineers within the power cable industry as to how current trends in the cable industry will influence future cable designs, particularly with polymeric insulation, lapped dielectrics, and improved diagnostic techniques. The use of high-temperature superconductors and designer polymers as well as the possible availability of conducting polymeric materials is also considered.
The paper first reviews how the design of distribution cables has differed historically around the world, the major differences being allied to the systems. Designs largely have been divided into two main categories: those countries following U.K. and European practices, and those having adopted the U.S. system design. However, these differences, such as the use of three-phase cables in the U.K. as opposed to single-phase cables in the U.S., are not so obvious nowadays. Installation practices are becoming rather more standardized, such as the use of ducts, directional drilling, etc. The predominant primary insulation is cross-linked polyethylene (including tree-retardant XLPE), which is used all around the world. Some constructional differences such as the "dry" and "wet" designs persist. The paper then discusses cables from the mid-twentieth century projected into the twenty-first century. Highlighted are the opportunities that will present themselves in the twenty-first century: fluid-filled cables, XLPE cables, intelligent cables, and designer polymers that optimize performance and economic advantages of buried cables. It then focuses on economic trends, power generation trends, lower-cost underground systems, overhead line/underground cables, and materials and environmental trends including use of high-temperature conductors to up-rate overhead circuits. The trend will be toward greater security and utilization using on-line diagnostics, greater circuit diversity due to distributed generation and lower cost cable systems, and extensive use of polymeric materials having low environmental impact.
A futuristic view of energy cables in the year 2050 is presented. Discussed are the elements of the "info-energy cable," the advantages of the cable technology, and the advantages for the network configuration. A realistic view of tendencies in cable systems technology over the next decade is outlined. Also discussed is choice of cable for subsea power links: choice of cable design that exists for subsea power links, the merits of the various designs, installation of submarine cables, protection of submarine cables, new challenges in HVdc submarine cable systems, and future developments. The manufacture and installation of long continuous lengths of subsea power cable is discussed with reference to some key installations. The paper goes on to examine the Kontex HVdc link between Denmark and Germany. The cable link has been in commercial operation since 1996, and with a total length of 172 km and a transmission capacity of 600 MW at 400 kV is still unique worldwide. Details of the link together with its installation and commissioning are explained.
Gas-insulated transmission lines are also discussed together with whether they are ready for real-world transmission systems.
Keywords: HVdc cables; ac distribution cables; gas-insulated transmission lines; high-pressure fluid-filled cables; multifunctional cables; polyethylene and cross-linked polyethylene cables; polymeric cables; submarine power cables; superconducting cables; underground power cables
Document Type: Research Article
Affiliations: University of Glasgow, Glasgow, United Kingdom
Publication date: October 1, 2003