HV Cables | Underground Cable Tunnel Pull 400kV By ABB
Published 06 Jul 2021
HV Cables | Underground Cable Tunnel Pull 400kV By ABB
Cable Pulling & Laying
ABB manufactured, installed and commissioned the 400kV cable for the National Grid’s largest ever tunnelling project, called ‘The London Connection’, a 20km long 400kV underground cable to supply central London which was energised in 2005 and which was at the time one of the longest 400kV underground cables in Europe.
The need
With electricity demand in North West London and the City increasing twice as fast as the national average and projections showing that this growth would be sustained for a decade, National Grid set out a project called The London Connection designed to create a three phase high voltage supply for North West London and the City.
Essential to National Grid’s future licence to operate, the connection linked Elstree to St John’s Wood through a new three metre diameter, 20km long tunnel to a new £60 million substation, also constructed by ABB.
Project details
ABB manufactured a total of 61km of high-voltage cable using cross-linked polyethylene (XLPE) insulation technology, which eliminates the need to use old-fashioned oil and high maintenance gas filled cables. A similar ABB 400 kV XPLE underground cable has been in service in Berlin since 1998.
The cable was manufactured at our own plant in Germany and underwent a one-year duration test at an independent test facility, where it was signed off as fit for purpose.
Three phase HV AC cable installed in the tunnel
ABB supplied 150mm diameter cable for three 20km lengths – one for each of the three phases of the supply. At a total weight of 2,440 tonnes, the act of pulling the cable along the length of the tunnel was an element of the project that threw up significant challenges.
ABB delivered the cable to site on 63 massive separate cable drums and pulled it through the tunnel in three sections at intermediate shafts along the length of the tunnel, with the longest cable pull being around 7.5 km. ABB used a special arrangement of cable pulling equipment for the safe and smooth installation through the tunnel. A post-pulling cable insulation test proved that the cable was ready for safe service as part of the grid.
As a full turnkey project, ABB’s successful installation of the cable and connection to the new St John’s Wood substation meant that the London Connection was ready for National Grid to operate in summer 2005 and it has been in operation providing energy to London consumers ever since.
Cable Pulling & Laying Equipment
Suppliers & Distributors
Thorne & Derrick distribute the most extensive range of Low & High Voltage Cable Installation & Electrical Distribution Equipment to the Power Transmission & Distribution industry in the onshore and offshore wind, solar, rail, oil/gas, data centre, battery storage and utility sectors – this includes the most extensive range of Cable Pulling & Cable Laying Equipment to enable the installation of low, medium and high voltage power cables into underground trench or duct.
We service UK and international clients working on underground cables, overhead lines, substations and electrical construction at LV, 11kV/33kV and up to EHV transmission and distribution voltages.
Key Products: MV-HV Cable Joints & Terminations, Cable Cleats, Duct Seals, Cable Transits, Underground Cable Protection, Copper Earth Tapes, Cable Jointing Tools, Feeder Pillars, Cable Ducting, Earthing & Lightning Protection, Electrical Safety, Cable Glands, Arc Flash Protection & Fusegear.
Distributors for: 3M Electrical, ABB, Alroc, Band-It, Cembre, Centriforce, CMP, Elastimold, Ellis Patents, Emtelle, Furse, Lucy Zodion, Nexans Euromold, Pfisterer, Polypipe, ProGARM, Prysmian, and Roxtec.
- Scope –single-source supply of extensive range of products
- Stock – a multi-million pound stock holding provides complete global supply solutions
- Staff – technical support from a trained, proactive and friendly team
- Delivery – UK stock turnaround with express logistics to all international destinations
Thorne & Derrick International, based in the UK, are delighted to announce they have entered into an Approved Stockist Agreement with SEB International, the market-leading Cable Laying Equipment manufacturer.
