Transforming Burbo Bank Wind Farm

Collett transport Burbo Bank Transformer

Collett’s girder bridge delivers two 200 Tonne transformers destined for the onshore substation at Burbo Bank Wind Farm.

With construction underway on Burbo Bank Extension, DONG Energy required the delivery and installation of two 200 Tonne transformers at their onshore substation.  Once constructed, the substation will allow the 32 turbine offshore wind farm to connect to the national grid and begin generating power for over 180,000 homes.

Handling delivery of the transformers into the UK, SDV UK Ltd called upon the expertise of Collett to facilitate the ship’s discharge at the Port of Mostyn and the following transport to site of the two cumbersome cargoes.  With the ship arriving in July the Team were onsite to undertake the project with two ballast tractors and a 14 axle modular hydraulic flat top trailer.

Having already undertaken the required planning for discharging the vessel the Collett Heavy Lift Team, operating under CPA Contract Lift conditions, began the task of unloading the components from the hull of the ship utilising a 750 Tonne crane.  Each load was lifted from the ship and delivered to the awaiting 14 axle trailer.  The loads were then transported to an agreed holding position at the port where they were stored on stools until a suitable construction stage at the substation allowed for delivery.

The delivery of the two loads took place in September, but due to the size and weight of the transformers this was nowhere near an everyday undertaking.  Each transformer measured 11,400mm (L) x4,400mm (W) x 4,750mm (H) and weighed 200 Tonne, therefore a more specialist method of delivery had to be devised to facilitate the loads owing to height and structure restrictions en-route.

Port of Mostyn

In order to utilize the abnormal load exit at the Port of Mostyn, the loads were required to travel over a level crossing.  Usually this wouldn’t be an issue, however due to the weight of the loads and the size of the rail track Collett were required to obtain official track possession.  This allowed the two transformers to travel over the level crossing on modular trailers.  The loads would then be positioned in a local layby, approximately one mile from the Port, for transhipment from the 12 axle flat top to the 550 Tonne capacity girder bridge for onward transportation.  Not a simple task of lifting from one to the other, the loads once again had to be positioned on stools whilst the Collett Team took to building the modular girder bridge around the load. 

Once constructed, the overall dimensions of the combination and load required specialist route planning from the Collett Consulting Team, providing traffic management plans and route analysis ahead of the project to ensure a safe delivery.  This required the Team to pore over mapping data for several days, intricately planning the route to prove suitability, undertaking swept path analysis and conventional surveying techniques to plan the project to perfection.

The final route plan highlighted a weak bridge, too fragile to accommodate the girder bridge and load, consequently the Team obtained a temporary traffic restriction order, which required a 12 week approval process. 

Heavy Lift Performed on a Transformer

This then allowed Collett to contraflow the A55 dual carriageway in the wrong direction, therefore avoiding the bridge and allowing the combination to re-enter the A55 in the correct direction.

Travelling under police escort Collett’s 10 man Heavy Transport Team departed from the Mostyn layby one late evening in September.  Travelling throughout the night the girder bridge and its load passed along the rural roads of Flint before joining the A55 for the 15 mile journey to site in St Asaph arriving just as the sun began to rise. 

Once on site the Team unloaded the transformer and utilising our jacking & hydraulic skidding system manoeuvred it into position onto a plinth and aligned onto anti vibration pads.  Fast forward five days and following the exact same procedure, the second transformer was collected from the layby and delivered to site.