Synchronous condensers are essential in making the UK’s transition to renewable energy possible. Most renewable energy sources are variable, falling in output as wind or sunshine reduces, for example, and typically do not use rotating generators, so lack the inertia that coal and gas-fired power stations traditionally used to provide. Synchronous condensers help stabilise and regulate the power supply to electrical grids, by providing the required inertia that a stable electrical system needs. Civil engineers play a key role in civil and structural aspects of the installation and movement on site of these machines, and designing the buildings accommodating these devices, which weigh hundreds of tonnes, spin thousands of times per minute, and emit a significant noise.

As the use of this technology increases across the UK energy network, WCS is involved in a number of synchronous condenser projects. From tender stage to detailed design, our engineers can offer key insights into how best to manage the challenges involved.

The practicalities of work involving very large devices

“One project we are working on involves synchronous condensers weighing approximately 300 tonnes,” comments WCS Director Nick Lowe. “Which, of course, comes with a set of challenges to navigate: is there room to bring them onsite and then into place? Can the weight be borne throughout the route? Temporary works need to be considered carefully in these projects. As power and energy specialists, we often work with transformers of similar size, so many points are familiar.” Read more about our work with transformers, here.

Overcoming these challenges may involve the design of new roadways to enable their transportation to a site or the assessment of current roads to check suitability; specialist modelling and surveying are also used to ensure vehicles bringing in the equipment will have room to move and turn.

Depending on the site, WCS might use Swept Path Analysis (SPA) software to confirm vehicle paths are correct, and we may also need to complete ground or condition surveys, as well as loading calculations. Photogrammetry, converting photos into a precise 3D model, is sometimes used to formally verify that transportation and installation can proceed.

Experience is key to delivering project success. This includes understanding the order of works and being aware of specific challenges raised by the project site, such as access or topography. Based on previous projects, WCS can identify potential challenges before they become issues. For example, it might be necessary to hoist equipment in by crane prior to placing a roof over the devices. If cranes are used, temporary works design must include space and foundations for them.

Engaging civil engineering support early at the tender stage can be advantageous. A specialist engineering consultant can offer invaluable advice and provide initial designs that deliver the planned works in the most efficient and cost-effective way.

Mitigating for noise and vibration

When working with synchronous condensers, managing the acoustic impacts of the technology is an important consideration. Nick explains: “One challenge specific to these projects is the degree of vibration these devices produce, which can be so large that foundations must be separated from the rest of the building by a movement joint.”

Noise accompanies the vibration, meaning designs must incorporate acoustic cladding. Temperature regulation and noise attenuation can conflict on these projects: vent placement, for example, must balance the need to let air pass freely with the need to prevent noise from doing the same.

Connecting the synchronous condenser

Control cables & HV power cables will always be needed, so the design will involve multiple cable routes across the site, either buried cable routes / trough routes or elevated / culverted gas-insulated busbars for the HV connections. New HV cable routes for infrastructure projects are sometimes kilometres in length and take months to manufacture, and cables must be laid or pulled into place if installed into a pit and duct system, a process that can potentially damage the cable or the duct in which it is run.

New synchronous condensers may be installed on an existing site to increase capacity, and undertaking careful design can help ensure cabling is as efficient as possible, but also works around the existing cables and services already present at the location. Alongside this, by using cable-pulling calculations where needed, we can avoid expensive and time-consuming setbacks for the entire project. Learn more about our expertise in this area here.

Planning ahead – from coolant containment to whole lifecycle planning

Nick adds: “While other devices we work with regularly, like transformers and battery energy storage systems, can often be placed outside, that’s rarely the case with synchronous condensers in this country due to constraining temperature tolerances and noise attenuation requirements. The cooling systems that synchronous condensers require are sufficiently heavy that they will typically require additional foundation work.

Mitigating for future issues is a key benefit of working with specialists, for example, cooling brings additional considerations for the civil engineering of these projects, including when designing drainage for the site. Our engineers must incorporate a suitable bund to contain coolant, should it ever leak from the large cooling systems.

Our design work takes every stage of a site’s use into consideration, from the temporary works and construction phase, to the operational requirements of the buildings and access, and extends to planning for replacement and end-of-life issues. Whole lifecycle planning is imperative; staff will need to operate and maintain equipment in safety and in an acceptable noise environment. Typically, decades will pass before this very heavy equipment is removed and possibly replaced, but this must be planned into the designs from the outset and is one of the key regulatory duties of a civil engineer under CDM.

Case study – supporting Hitachi Energy

With our support, Hitachi Energy won a project to extend the existing Eccles 400kV substation with new buildings to house two new synchronous condensers. Read more about the project, here.

The requirement here was for hybrid synchronous compensation,” explains Nick. “That means a conventional synchronous condenser paired with a device called a STATCOM (Static Compensator). Synchronous condensers of every type will become more common as renewables replace fossil fuels. We became involved with these systems early because they are associated with a specialty of ours – substations – and we value opportunities to expand our expertise and cement our status as a specialist here too.

We are happy to support clients in whichever way they need; in this case, our role was twofold. At tender stage, the team at Hitachi Energy turned to us to visit the site and work as an integral part of the bid capture team with them throughout the year-long tender phase. Support included presenting proposed designs as part of Hitachi’s presentation to the end client, SP Energy Networks.

When the contract was won, we were asked to supply a Lead Civil Engineer to be embedded onsite to oversee all works, and to provide civil engineering assurance, checking documents and drawings to ensure they are in accordance with UK standards and otherwise appropriate. During the delivery phase, WCS will have staff based onsite overseeing the works and will carry out the role of Temporary Works Coordinator.

Working with Whitfield Consulting Services

As specialists in civil engineering design for the power and energy sector, our role is to facilitate for clients, anticipating needs and problems based on experience, and finding the most cost-effective solution that is robust and compliant. We are currently supporting clients on a number of other synchronous condenser projects in Great Britain, and on a number of projects in Ireland, the presence of our Armagh office being especially valuable in the latter case.

Alongside our work on synchronous condensers, we work on a range of projects from Battery Energy Storage Systems (BESS), through grid connections to EV charging, which are all vital to the UK’s shift to renewable energy and solving the challenges that come with this ambitious goal. We’re proud to work with clients delivering sustainable infrastructure and positively contributing to the UK achieving net zero in the future.

If you need a partner with experience working on synchronous condensers, please get in touch with us, via our contact page.