Powersystems is proud to share a major milestone in the delivery of a strategic 275 kV substation and Battery Energy Storage System (BESS) infrastructure project, reinforcing our role as a trusted partner for high‑voltage grid connections across the UK.
Building on the progress outlined in our earlier project update, Powersystems has now successfully advanced multiple critical work packages on this complex 275 kV grid connection, demonstrating our capability to deliver at transmission voltage level — from engineering and manufacture through to installation, testing and commissioning.
As part of the Stability Pathfinder Phase 2 initiative for National Grid ESO, the Coylton BESS will provide 50 MW of energy storage with a 2-hour duration, connecting to the Scottish Power 275 kV transmission system via the Coylton 275 kV Substation.
Major 275 kV Delivery Milestones Achieved
Significant progress has been made across protection, switchgear, cabling and commissioning activities, including:
- 185 MVA Transformer and 275 kV Circuit Breaker protection panels installed and 90% site tested
- 275 kV Air Insulated Switchgear (AIS) designed, supplied and installed by Powersystems, now undergoing in‑house testing
- DSM panel inspection completed in the control room
- 33 kV Schneider GHA switchgear in site testing, with commissioning 80% completed
- 275 kV cable installation completed, with remaining sections prepared for handover to the client
- 275 kV cable installation within the Scottish Power compound, currently being prepared for cable sealing end installation
- Scaffolding installed at the 275 kV AIS to safely enable cable sealing end works
Each of these elements plays a critical role in enabling a safe, compliant and high‑performance grid connection at transmission voltage level.
Why 275 kV Matters to the UK Grid
Operating at 275 kV places this project firmly within the UK’s transmission‑level network, supporting the movement of large volumes of electricity from generation sources — including renewable and BESS assets — into the wider Grid.
Unlike lower‑voltage distribution connections, 275 kV infrastructure demands exceptional engineering control, precise protection coordination and a deep understanding of Grid Code compliance. These connections are essential to:
- Support large‑scale renewable generation and energy storage
- Improve grid resilience and stability
- Enable faster decarbonisation of the energy system
- Reduce congestion by moving power efficiently across long distances
Delivering at 275 kV requires not only specialist design expertise, but also proven capability in high‑voltage protection systems, switchgear integration, control panels, and complex on‑site testing — an area where Powersystems continues to excel.
End‑to‑End High‑Voltage Expertise You Can Trust
This project highlights the breadth and depth of expertise required to deliver transmission‑level infrastructure. From protection panels and AIS equipment through to cable installation and commissioning, Powersystems is providing a fully integrated high‑voltage solution.
Our in‑house teams manage:
- High‑voltage protection and control design
- Manufacture and factory testing of protection panels
- Site installation at 275 kV
- Commissioning and final testing
- Coordination across transmission and distribution interfaces
This approach reduces risk for clients and ensures seamless delivery on some of the UK’s most technically demanding grid connection projects.
Proven 275 kV Protection Capability
This project builds on a growing portfolio of successful schemes delivered by Powersystems. A recent example includes our work at Coylton Greener Grid Park, where Powersystems delivered specialist 275 kV protection panels to support Scotland’s evolving energy infrastructure.
By combining repeatable high‑voltage delivery with tailored engineering solutions, Powersystems continues to support major grid upgrades and BESS developments nationwide.
Supporting the Future of Energy
As the UK accelerates towards net zero, projects like this are essential to unlocking renewable capacity and strengthening the transmission network. Powersystems is proud to play a hands‑on role in delivering mission‑critical 275 kV infrastructure that enables a smarter, greener and more resilient Grid.
Let’s Talk About Your 275 kV Project
If you’re developing a 275 kV grid connection, substation upgrade or BESS project, Powersystems has the experience, in‑house capability and proven track record to support you — from concept through to commissioning.
Contact our high‑voltage specialists today to discuss how we can support your next project.
Notes to Editors:
Contact Information:
- This article is written by Jules Daly, Marketing and Communications Manager at Powersystems.
- Email jules.daly@powersystemsuk.com Telephone 01454 318000
- Photography Copyright please credit all images used to powersystemsuk.co.uk
Powersystems are powering the transition to a sustainable future
Powersystems: The High Voltage Specialist of Choice
Powersystems is a leading employee-owned high voltage electrical engineering specialist with over 49 years of experience delivering safe, efficient, and high-quality infrastructure solutions across the UK.
As the first Lloyd’s NERS-accredited Independent Connection Provider (ICP), we have been delivering contestable grid connections up to 132 kV for over 29 years. Our trusted expertise spans the full project lifecycle—from design and installation to commissioning—supporting clients across renewable energy, utilities, and industrial sectors.
Since 2000, Powersystems has connected over 10 GW of renewable energy to the UK grid, including onshore and offshore wind, solar, hydro, tidal, and battery energy storage systems (BESS). We’ve also delivered critical infrastructure for electric vehicle charging, CHP, STOR, rotating stabilisers, and private wire networks.
Working in partnership with developers, contractors, and DNOs, we’ve connected 30% of the UK’s onshore wind farms—playing a vital role in the transition to Net Zero by 2050.
Our commitment to safety, sustainability, and innovation is embedded in our ISO-accredited integrated management systems and our ‘Priority No.1’ health and safety culture. We continue to invest in people, technology, and partnerships to remain the high voltage specialist of choice.
As an employee-owned business, Powersystems empowers every team member to contribute to our shared success. Our ownership model fosters a culture of collaboration, accountability, and continuous improvement—ensuring we deliver excellence for our clients, safely and efficiently.