Cable systems in multi purpose or shared structures

With the increase in demand and the challenges posed by the design and installation of high voltage (HV) and extra high voltage (EHV) cables in congested right of ways, structures such as tunnels and bridges for multipurpose use are becoming an attractive option. Cigre’s working group B1.08 met in various parts of the world and developed engineering guidelines on Cable Systems in Multi Purpose or Shared Structures during 2006-9. This working group had electrical cable engineers from Australia, Austria, Canada, France, Italy, Japan, Korea, Netherlands, Singapore, Spain, Sweden, and the United Kingdom, and a civil engineer from the United States. With the increase in demand and the challenges posed by the design and installation of high voltage (HV) and extra high voltage (EHV) cables in dense urban and other congested right of ways, structures such as tunnels and bridges for multipurpose use are becoming an attractive option. They offer reduced overall costs, environmental advantages and less disruption to the community during installation, maintenance and replacement of cables and other services. In the Cigre’ WG B1-08.9.3, the reader can follow Sections 1 to 5 and review the examples described in Section 8 to decide if a shared structure is appropriate. If the decision is to use a shared structure, Sections 6 and 7 offer expert guidance on various technical and administrative issues, forming a wonderful reference document on the design and implementation of such a system. Section 8 indeed is a review of the international experience of HV cables in multipurpose or shared structures, offering prior established experienced in this field. Future trends are summarized in Section 9. Section 10 offers a list of 60 references. A comprehensive appendix presents the results of TF B1-14, which surveyed through comprehensive questionnaires on the global use of cables and structures. The same issue for Gas Insulated Lines (GIL) has been reviewed by JWG B3/B1.09 in the TB 351 "Application of Long High Capacity Gas Insulated Lines in Structures." Scope of Work Due to the complexity of cabling in general, this study group elected to mainly deal with cable systems of 50 kV and above in multipurpose and shared structures where it felt that future investments are most likely to be made. There is no limitation to applying these principles, however, to cables of lower voltages.