Efficient and Effective

Small Bore Cable Replacement Technology

Project Data

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End date:





The project aims to demonstrate alternative techniques to the traditional replacement approach for EHV cables employed by GB DNOs. The project will trial identified techniques at a number of sites where there are circuits of small bore cable.

What is the project about?

The Small Bore Cable Replacement Technology project intends to demonstrate emerging techniques for the replacement of EHV cable as an alternative to traditional open cut lay techniques currently used. Technologies have been trialled on large cross section area cables in rural locations for the replacement of fluid filled cables. These however have not yet been proven on small bore cables in urban environments that may be in close proximity to other circuits or services. Therefore this project plans to trial these emerging techniques at small bore cable routes in urban environments that are close to other circuits and cables. The main risks for the project will be impact on customers whilst carrying out the trials due to failure of the new methods being tested. For this reason initial trials will be carried out on inactive sections first.

How we’re doing it

Trial on electrically isolated cables

The purpose of this phase will be to test the new technology in real ground conditions – in close proximity to other non-UK Power Networks assets and in close proximity to other (inactive) circuits. During this trial other UK Power Networks circuits in close proximity will be closely monitored to confirm the impact of the new technology on them and to identify if risk of damage to adjacent assets can be minimised.

Trial on temporarily electrically isolated power cables

This second phase will only be carried out subject to successful outcome of the first phase of each technology. In this phase the technology will be tested on electrically active cables. These will be cables which have been temporarily isolated due to faults, leaks or ongoing repairs. The technology will be trialled on sample routes where each technology will be trialled on a different section where practicable.

What we’re learning

The main learning that will be shared with other DNOs is expected to include:

  • An improved understanding of the available suppliers and their alterative techniques for small bore cable replacement;
  • Tested new cable replacement technology;
  • Cost-benefit analysis of new technologies in comparison to existing practises.
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