This project will trial new devices to reduce leakage from pressurised cables, by operating the cables at lower pressure, to such an extent that their operational life can be extended. It is estimated this could give our customers a potential benefit of £8.58m by 2023.
Within all GB DNOs there are approximately 6,607 km pressurised cables in operation at 132kV, 66kV and 33kV. These cables were installed since the 1920s, with the majority being installed in the 1960s. The current accepted best practise for repairing poor condition cables is to either carry out a repair on the localised area or replace the full length of cable in that section. This is a costly process and makes up a significant part of the network maintenance programme.
By reducing the pressure of pressurised circuits leakage will be reduced, however all current methods of pressure reduction rely on making an assessment of the minimum required pressure based on historic design guidelines which used empirical data from the 1960s. No active control mechanism was installed to manage the cable pressure. As fluid lost is a key indicator of asset health of pressurised cables, by actively reducing leakage from pressurised cables the asset life of these assets can be extended.
The project will develop a control strategy and system using technology to enable monitoring and active control of pressurised cable systems. The goal of this will be to enable the pressurised cable to run at a lower pressure, thus reducing leakage along its route. A system will be developed that would consist of:
A system consisting of above will developed to to be trialled on two different locations of UK Power Networks.
An active pressurised control unit to manage the pressure of fluid filled circuits has never been trialled before in GB distribution networks. This will be an innovative approach to maintain fluid filled circuits.
The project aims to demonstrate new ways network operators can manage fluid filled circuits increasing network reliability and keeping the cost down to customers. New systems developed as part of this trial will help extend the lifecycle of an existing asset and reduce the number of cable failures.