Delivering full 132/33 kV infrastructure and 181.5 km of 33 kV cabling for a major Welsh onshore wind development
Project Snapshot
| Client | Innogy Renewables UK (now RWE Renewables) |
| Location | Clocaenog Forest, North Wales |
| Project Value | £20 million |
| Duration | 18–24 months (electrical works June 2018 – Sept 2019) |
| Market Sector | Onshore Wind — Renewables |
| Services Delivered | Full Electrical Balance of Plant (EBoP) |
| Powersystems Fact | Powersystems’ wind farm renewable energy team has connected 24% of all UK land‑based wind generation. |
Clocaenog 96 MW Wind Farm Case Study
Download the full Clocaenog Wind Farm Case Study to explore how Powersystems delivered the complete 132/33 kV Electrical Balance of Plant for this 96 MW onshore development in North Wales. The PDF provides a detailed overview of our transformer, switchgear and protection installation, 181.5 km of 33 kV cabling, SCADA integration and full commissioning works for all 27 Vestas turbines. Ideal for engineers, developers and stakeholders seeking deeper technical insight into a large‑scale renewable energy project providing clean electricity for more than 63,800 homes.
Client & Site Background
Clocaenog Forest Wind Farm is one of Wales’ largest onshore renewable energy developments, built within the 1,600‑hectare Clocaenog Forest to the southwest of Denbigh. The Welsh Government designated this area as suitable for large‑scale renewable generation, enabling Innogy Renewables UK to develop a 96 MW wind farm comprising 27 Vestas 3.6 MW turbines.
Once operational, the site generates enough clean electricity to meet the needs of 63,800 UK homes, delivering long‑term environmental, energy‑security and community‑benefit outcomes.
Powersystems was appointed by Jones Bros Civil Engineering to deliver the full Electrical Balance of Plant, including all 132 kV and 33 kV systems required to connect the wind farm into the SPEN network.
The Challenge
As a forest‑based development, Clocaenog presented engineering and environmental constraints:
- Installation of 181.5 km of 33 kV cabling through dense forestry
- Construction of new 132/33 kV grid‑connection infrastructure
- Delivery of substation works adjacent to SPEN’s 132 kV Bryn Bach compound
- Complex earthing requirements across multiple turbine bases
- High volumes of cabling, jointing and switchgear installation
- Tight programme deadlines across civil, electrical and turbine workstreams
Powersystems’ multidisciplinary HV engineering capability ensured full coordination and safe delivery.
Our Engineering Solution
Powersystems delivered a full turnkey Electrical Balance of Plant solution, covering all HV, LV, protection and SCADA systems.
132 kV Grid Connection Infrastructure
- 2 × 70 MVA 132/33 kV grid transformers and associated circuit breakers
- 145 kV dead‑tank circuit breakers for Point‑on‑Wave switching
- 145 kV double‑break disconnectors
- 132 kV structures and overhead busbar arrangements
- Compound earthing and integration of the adjacent SPEN Bryn Bach earth grid
33 kV Substation & Wind Farm Systems
- Duplicate 33 kV Schneider WS switchboards to feed six WTG arrays
- Bus‑coupler configuration for transformer outage flexibility
- Full 33 kV array system:
- 181.5 km of 33 kV cabling
- Power, fibre‑optic and earth cables
- Turbine jointing and terminations
- Cable trenching within active forestry operations
Protection, Controls & Communication
- MiCOM protection relays for transformer and network protection
- Schneider P849 relays for SCADA interface
- GE combined CT/VT measurement equipment
- Point‑on‑Wave controllers for 132 kV switching
- SCADA integration across all turbine and HV systems
Building & LV Systems
- Control building construction and full internal fit‑out
- Lighting, small power, heating, fire detection and intruder alarms
- LVAC changeover panel and auxiliary power systems
- Substation and compound earthing networks
Project Process
- March 2018 — Mobilisation and groundworks
- 2018 — Trenching, access roads, cable ducts across forested terrain
- Jan 2019 — Turbine component deliveries commence
- 2019 — Installation of all 132 kV substation equipment
- 2019 — 33 kV cabling, jointing, protection and SCADA systems completed
- Sept 2019 — Commissioning activities progress; 90% of cabling installed
- 2020 — Final site completion and wind farm operational
Project Facts & Figures
- 27 × 3.6 MW Vestas turbines
- 96 MW installed capacity
- 2 × 70 MVA 132/33 kV transformers
- 181.5 km of 33 kV cabling installed
- Size of site: 1,600 hectares
- Enough energy for 63,800 homes
- SPEN grid connection at 132 kV
- Full NERS‑accredited ICP scope
Technical Specifications
132 kV Primary Systems
- 145 kV dead‑tank circuit breakers
- 145 kV double‑break disconnectors
- GE MiCOM P643 and P14N relays
- SynchroTeq Plus Point‑on‑Wave switching
- Combined CT/VT metering units
33 kV Secondary Systems
- 2 × Schneider WS switchboards
- 33 kV turbine feeders and array circuits
- Cable joints (Cable Jointing Solutions)
- Earth tape, Cadweld+ connections and full compound earthing
SCADA & Controls
- IEC‑based turbine monitoring
- HV SCADA interface panel
- Protection alarms, intertrips and control circuits
Watch a short film on the Cloacenog Forest Wind Farm
Partnerships
- Innogy Renewables UK (now RWE) — Client
- Jones Bros Civil Engineering — Principal Contractor
- SP Energy Networks (SPEN) — DNO
- Powersystems — Electrical Balance of Plant Contractor
Key Risks & Mitigations
- Forestry‑based HV cable installation – Mitigation: Managed routes through working forest areas; protective excavation methods.
- 132 kV switching & grid compliance – Mitigation: Installed advanced PoW switching, transformer protection relays and full commissioning.
- Remote upland environment – Mitigation: Weather‑resilient planning, phased trenching and controlled lifting.
- Environmental land management – Mitigation: Careful cable trenching, silt control, habitat protection and reinstatement.
Environmental Considerations
- 96 MW clean‑energy generation
- Enough electricity for 63,800 homes
- Supports Welsh renewable‑energy policy
- Built in a managed forest with low‑impact cabling routes
- Long‑term natural resource stewardship
Economic & Community Benefits
- £768,000 annual community fund supporting local organisations
- More than £118 million invested in regional clean‑energy infrastructure
- Jobs created and safeguarded through 96 local grants
- Strengthened North Wales supply chain
- Long‑term clean‑energy price stability
Future Prospects
Clocaenog Wind Farm is now a major contributor to Wales’ renewable‑energy supply.
Its large‑scale infrastructure and long asset life demonstrate Powersystems’ capability to deliver complex HV systems in challenging environments.
Related Projects
- South Kyle 240 MW
- Limekiln 108 MW
- North Kyle 212 MW
- Kennoxhead 174 MW
- Pen Y Cymoed 228 MW
Delivering a 132 kV wind farm or large scale renewable project?
Powersystems provides complete HV design, installation, protection, SCADA and commissioning services for major renewable‑energy developments across the UK.