HomeProjects New high-voltage connection under the Haringvliet

New high-voltage connection under the Haringvliet

Engineering film Joulz is currently constructing a new high-voltage connection between Middelharnis and Geervliet, commissioned by Stedin. The 18 kilometre-long connection is part of improvement works to the electricity grid on Goeree- Overflakkee.

The connection runs under the Haringvlietm which is around 5 kilometres, which are connected at the halfway point. The sections are now being joined together on opposite sides of the Haringvliet at Middelharnis and Zuidland. 126 sections of 20 metres - an impressive length.



The work island

In order to cross the water, V&SH has placed a work island in the middle of the Haringvliet: a sheet-pilling trench filled with sand from this former estuary. The drilling rig, on a pontoon built in Dordrecht, is moored to this. There is a second drilling rig on the shore at Middelharnis. This will be used to implement the meet-in-the-middle technique. V&SH will be drilling 1,500 metres on one side and 1,000 metres on the other. Once the intercept shaft has been created, the pilot hole can be vacated. V&SH will then draw the first casing tube through. The drilling has now been completed. This means that the connection on the Middelharnis side is ready. In the second drilling phase, V&SH will connect the island to the Zuidland side.

Patent pending

The pontoon will then return to Dordrecht to collect the winches required to draw the cables through the tube: three reels weighing 68 tonnes, which will be delivered from Germany by ship. During the reconstruction, the work island will be excavated and V&SH will place small pontoons supporting the connecting frame here. This will be used at al later date to connect and sink the two halves of the crossing. So V&SH is working with pioneering methods in all areas of this project. This applies to the lengths involved as well as the innovative technique devised to draw the cables through. There is even a patent pending on this. The intensive cooperation between the different departments on the technical design, drilling and cabling work is remarkable. It's a great example of the cooperation within our company.


V&SH is currently working on the cable-drawing operation under the Haringvliet. The first part of this operation has been completed succesfully. The next part will take place in week 42.

Facts and figures