As ABB’s contract to deliver HVDC converter stations in the Hampshire and France for the IFA2 link hits its half-way mark, Gavin Pritchard, ABB Project Director for IFA2, shares an update about the challenges of leading a construction project with sites on both sides of the English Channel.
We’re around halfway through our 43-month contract to build converter stations for the 1,000 MW IFA2 HVDC link. National Grid and French transmission operator RTE are building the link under the IFA2 joint venture company as a new interconnection between the British and French transmission systems.
Having been appointed to deliver the converter stations, we’re on track for energisation in Q1 2020, with handover in Q4 2020.
I’m responsible for overseeing work on both sides of the Channel and we currently have around 30 or 40 people at each site, although that will increase considerably over the next few months.
The converter stations will be based on fourth-generation HVDC Light voltage source conversion (VSC) technology, which I’m familiar with, having recently worked on the project to deliver SSE’s Caithness Moray link.
One approach that is working well is that we’re sharing an office with our client. This is great in terms of problem solving, communication of issues and gaining our client’s involvement in dealing with issues. It also gives a high level of transparency and visibility.
Northern termination point
IFA2’s northmost point will be the HVDC Light converter station that is currently under construction in Chilling, Hampshire. However, Chilling AC substation is several kilometres distant so IFA2 will also need an AC line to connect it to the grid – and this will take the form of a subsea link.
We were appointed before IFA2 received fully planning permission for the site. Therefore, our early project activities were focused on supporting IFA2’s local consultation, for example by making presentations to members of the public.
An important aspect of the site in Hampshire is its proximity to Solent Airport, a busy leisure airfield and business park, as well as local residents.
Having nearby residential neighbours has led us to take special measures around noise. For example, we’ve implemented the best possible noise attenuation on the cooling fans for the transformers and the shunt reactors. We’ve also taken advantage of the open space to build bund as further noise attenuation.
To avoid any impact on the airport and business parks, we’ve taken special measures to contain radio frequency emissions from the power converters. Typically, all of our HVDC projects feature radio frequency shielding in the form of a Faraday cage around their converter halls. However, we’re taking extra measures at Chilling and will introduce complete Faraday cages in all of our buildings to completely eliminate any radio pollution.
Solid foundations
In terms of construction progress, we’re working with Morgan Sindall as our contracting partner in Chilling and so far have put in place the piling and concrete foundations for the converter buildings. More recently, we’ve been putting the groundworks in place for the concrete slabs, for example by creating drainage, ducting and earthing.
One unexpected benefit of the project has been the opportunity to support the education of local construction apprentices, who are studying at Fareham College’s nearby civil engineering facility. We’ve taken the opportunity to host the apprentices on site to show them the practical aspects of the topics that they’re studying.
For example, after they learned about piling, they were able to come on site and see piling in action. We also did some training with them around buried services as part of our Health and Safety Week initiative in October 2018.
We’re now starting to erect the first steelwork for the control building and the storage building, as well as creating concrete slabs and blast walls for the transformer bases and shunt reactors.
We are preparing the site for four transformers. In addition, two shunt reactors will be needed to absorb reactive power over the AC transmission line to Chilling AC substation.
These are due to arrive from Sweden via Portsmouth or Southampton docks in summer 2019, when they will be transferred to barges for the final few kilometres.
Converter station in Tourbes
Meanwhile, at the other end of the 230 km link in France, we are working with contracting partner Vinci Energies at a site adjacent to RTE’s existing AC substation at Tourbe substation in Normandy.
The site’s rural location means that it is not readily accessible by public transport, meaning we need to schedule site visits carefully to make the most of time. However, it’s also a benefit as we have not needed special measures for noise attenuation or radio frequency shielding.
Another comparison is that whereas Chilling was used to store munitions during the war, we only found trace materials. However, in Tourbe we unearthed a 500 lb British bomb and a 1,000 lb American one. Both were carefully removed and detonated.
