Visser & Smit Hanab has been commissioned by TenneT to construct a 380 kV cable crossing under the North Sea Canal, including the substations on each bank. To minimise the disruption to shipping along the navigable channel, the decision was made to cross the water underground.
The water crossing will be accomplished with two directionally drilled boreholes, 10 metres apart and each 775 metres long. After the first boring is completed, the project team will insert the pipe casing into the borehole. The casing is made of Ø 508-mm steel pipe joined by our welders and fitters onsite. Once the first pipe casing has been installed, the second borehole will be drilled and its pipe installed.
V&SH will be using a technique in which 12 cables are bundled together to pull in the 380 kV cable connection. This allows us to install six high-voltage cables, including fibre-optic lines, in each pipe casing.
We will also be constructing substations on each bank. These are the points where the underground lines connect tot the electricity pylons.