Located off the Yorkshire coast
Allelys played a key role in the Hornsea 2 project by delivering and installing 11 units including two 84te shunt reactors, three 135te transformers, three 208te reactors and three 240te transformers.
The route from Immingham was suited for girder frame transport, however the limited space on site didn’t allow for such a large transport arrangement. Therefore a concept was developed to use flat top trailers. Due to the transport configuration then being over height for the route, a full route survey was instigated, live overhead cables and telecom wires were checked and a high vehicle link road was required to avoid a bridge that was too low for the transport.
A complex installation solution
There were four main areas of operation on site and a unique solution was required for each due to the different sizes and layouts.
The first two units (84te shunt reactors) were delivered to site using a 10 axle flat top trailer and installed using a 500te capacity mobile crane.
A set of three 135te transformers were then delivered using a 12 axle flat top trailer configuration. It wasn’t possible to use a crane to install these units due to the limited space, therefore heavy duty jacking and skidding equipment was utilised. Usually the skid track would be positioned to skid the unit directly to its final position, however this wasn’t possible due to columns and steelwork already installed on site. Through careful planning a unique solution was created to offset the skid track and then shunt the transformer into position. These reactors also needed to be rotated inside the plinth by skidding the reactor off the trailer, rotating it inside of the bund before being shunted into position using jacks and alignment gear.
The third set of units, three 208te shunt reactors, were delivered to site using a 14 axle flat top trailer configuration. They were installed using the same heavy duty jacking and skidding equipment, but this area of operation enabled the skid track to be positioned to skid the reactors directly into their positions.
The final set of units
Three 240te transformers were the last units within the Allelys scope of work. This installation phase posed a further challenge as the area of operation didn’t have the required space for the flat top trailer to deliver the transformers to the necessary position.
Therefore extendable beams were positioned on the trailers prior to the transformers being loaded. Retracted, these beams allowed the trailer to run on public roads at normal width and when extended enabled the units to be stooled off on site. The transformer units could then be transshipped to SPMT before being maneuvered into the offload area. The extended beams were then used to jack up the load, enabling the skid beams to be positioned and the extendable beams to be removed. The transformers could then be skidded into their individual bunds before being jacked down to final position.
