The aim of Phase 2 is to trial few circuits and confirm the satisfactory operation of the new SHFs in fluid filled cables representative of those in distribution networks and in FFC circuits. The project will also ensure SHF production and quality assurance at industrial production level.
The project will involve the production of a fully qualified SHF formulation which will be proven in both rig and field circuit trials. Sites will be selected within UK Power Networks’ licence areas to do the field trial on short and long circuits. Testing in the lab will be performed with UK Power Networks and Northern Power Grid cable and oil samples to ensure additive developed is for all the different types of fluid filled cables.
Phase 2 will cover a wide range of activities, intended to allow the rapid deployment of the technology upon the completion of the project. During the first stage, the project will focus on mobilisation and scale up prior to testing within Stages 2 and 3, including the transfer of the SHF formulation to a large-scale fluid supplier and the construction and commissioning of primary and secondary rigs. During this phase, fluid samples will be collected from FFC network for analysis, and provide short lengths of cable for cable aging and compatibility trials.
During Stages 2 and 3, the volume-produced SHF will be tested within the primary and secondary rigs to establish the performance of SHF over a range of conditions expected within operational cables. Upon the successful conclusion of rig trials, the SHF formulations will progress to circuit trials. During the final stages of the project, the system will be transitioned to business as usual to ensure that the system can be taken up quickly upon its conclusion.
When a fluid filled cable starts leaking, operational staff are mobilised to initially locate the leak and then (depending on its severity) repair it or replace the fluid filled cable. Both activities are very costly. Introducing the SHF into the leaking fluid filled cable (cheaper method than repairing or replacing FFCs) could reduce or even eliminate the need for repairing or replacing the cable.
Throughout the project, there is significant potential for new learning regarding the current condition of FFC circuits across the country, individual cable condition and that of the insulation oils in current use, as well as the potential for cables to accept SHF formulations that will not interfere with the operation of PFT tracers used for fluid leak detection.
There will be significant learning on the effectiveness of local leak site repair by SHFs in actual FFCs and on the effectiveness of the containment mode of action preventing leaking fluid from causing widespread environmental contamination. This learning is expected to lead to widespread adoption of the SHF technology on networks operating FFC circuits.