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Projects: Projects for Investigator
Reference Number NIA_NGET0136
Title Impact of Seabed Properties on Ampacity and Reliability of Cables (ICASE Award)
Status Completed
Energy Categories Renewable Energy Sources(Wind Energy) 50%;
Other Power and Storage Technologies(Electricity transmission and distribution) 50%;
Research Types Applied Research and Development 100%
Science and Technology Fields ENGINEERING AND TECHNOLOGY (Electrical and Electronic Engineering) 50%;
ENVIRONMENTAL SCIENCES (Earth Systems and Environmental Sciences) 50%;
UKERC Cross Cutting Characterisation Not Cross-cutting 100%
Principal Investigator Project Contact
No email address given
National Grid Electricity Transmission
Award Type Network Innovation Allowance
Funding Source Ofgem
Start Date 01 October 2012
End Date 01 July 2016
Duration 45 months
Total Grant Value £157,000
Industrial Sectors Power
Region London
Programme Network Innovation Allowance
Investigators Principal Investigator Project Contact , National Grid Electricity Transmission (100.000%)
Web Site http://www.smarternetworks.org/project/NIA_NGET0136
Objectives The objectives of the project include: Developing an understanding of the influence of geotechnical properties of the seabed on the performance of subsea cable and produce an improved method for specifying future connections. Investigating the impact of trenching and backfill on key physical parameters and their influence on cable thermal rating and long-term reliability. The success criteria of this project include: Initial report on the influence on cable performance of shallow water geophysical parameters. Report on the spatial and temporal variability of key seabed parameters and the design and selection of data. Report on the influence of seabed parameters on the operation and long-term reliability of cable assets. Final Report
Abstract Commercial interest in the use of subsea electricity transmission has grown significantly in recent years. Such cables form the backbone for offshore renewable energy generation infrastructure. They also offer the potential for a European Supergrid. HV subsea cables are frequently laid in trenches at the seabed and buried within local seabed materials, with little consideration of the thermal regime they will either enter or generate. The changing nature of the burial environment will have significant implications for cable performance; the thermal rating of these cables is limited by the ability to balance heat generation from electrical losses with transfer to the surroundings. Excessive temperatures distort the electric field in DC cable and prematurely degrade insulation and other components leading to early failure. The stability of the installed cable is dependent on the geotechnical properties of the seabed and these may change significantly both during installation and post-installation operation. With external cable temperatures approaching 60°C or higher, the host seawater-saturated sediments will endure thermal conditions at 1 to 2 metres depth typically only experienced following ~2 to 3 kilometres of burial at normal geothermal gradients. In the short term this could result in pore water convection and subsequent reduction of bed shear stresses and hence the erosion of the burial material whilst in the medium to long term they could promote diagenetic reactions between the sediment and pore waters such as mineral recrystallization, significant compaction, and partial induration. Research This research project will acquire, process and analyse a wide range of seismic and geotechnical datasets for HV cable routes across the UK continental shelf. Particular emphasis will be placed on both the spatial and temporal variability of key parameters such as: mineralogy, grain-size distribution, porosity/permeability, thermal conductivity, bulk density, bed shear stress and erosion. Data both pre- and post-installation will be investigated to look at both the impact of trenching and backfill on these key physical parameters and the variability of these parameters with the changing thermal regime. The project will link closely with a HubNet sponsored studentship (also starting October 2012) focused on the development of numerical and physical models of the changing thermal and physical regimes in these near surface environments. The student will work closely with colleagues from both National Grid and other cable operators.Note : Project Documents may be available via the ENA Smarter Networks Portal using the Website link above
Publications (none)
Final Report (none)
Added to Database 20/08/18