Cables with Long Electrical Sections

Completed

Other Power and Storage Technologies(Electricity transmission and distribution)

Applied Research and Development

ENGINEERING AND TECHNOLOGY (Electrical and Electronic Engineering)

Not Cross-cutting

Project Contact
National Grid Electricity Transmission

Network Innovation Allowance

Ofgem

01 April 2012

01 February 2017

64 months

£412,000

Power

London

Network Innovation Allowance

Project Contact, National Grid Electricity Transmission

The objective of this project are to provide National Grid with the following information; an understanding of the steady state and transient performance of cables with long electrical sections. An awareness of the failure mechanisms and life limiting factors of cable sheath voltage limiters (SVLs)Recommendations for the future of operation and maintenance of cables with long electrical sections This project is successful if the knowledge is sufficient to give recommendations for business implementation to improve the SVL cable issue.

In 2000 - 2002 midlife refurbishments were carried out on several cable circuits, mainly within London. As part of these refurbishment works the old link boxes were to be removed and new above ground pillars were fitted. At this time system studies were carried and it was found that the length of major electrical sections could be extended, therefore reducing the number of link pillars that were required, eliminating the need for extra easements to be obtained and reducing ongoing maintenance requirements. However it has been found that circuits where the length of the electrical sections has been extended are suffering from multiple failures of the sheath voltage limiters (SVLs) fitted to the cable bonding system. he method that has been proposed for this project includes: Report identifying the affected circuits and the extent to which they were modified Interim report on the analysis of failure data Design and commission on-line monitoring systems for SVLs Interim report on electrical modelling of affected circuits Report on laboratory testing of SVLs Report on forensic investigation of SVLs recovered from service Report on electrical modelling of affected circuits Interim report on the cause of the SVL failures Recommend remedial measures to reduce the instance of SVL failures and limit their consequences Final ReportNote : Project Documents may be available via the ENA Smarter Networks Portal using the Website link above

10/07/18