400kV WIND FARM

In August 2019 we installed two bores for two 400kV circuits to a new 400kV substation. The works were carried out using horizontal directional drilling techniques for Balfour Beatty and on behalf of Ørsted. This section of work SWDD installed was the final grid connection, as part of the Hornsea 2/ HOW 2 project, which is now delivering power to over a million homes.
 

After a stringent tender process, we were contracted

to design and install a dual-circuit horizontal directional drilling route to connect a new substation to the existing grid. The project was designed by SWDD as two drills of 190m, with 8m separation. Each bore was specified as 650mm, to house 3 x 250mm and 2 x 125mm SDR 11 Electric Ducts. 

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Some of the challenges faced included using a bore size smaller than typical, for the required ducts, but we did this to assist the client with the thermal resistivity values for the cable calculations. The directional drilling works had to cross the HOW 1 400kV cables, along with Centrica 400kV cables and also to drill beneath existing powerlines.