Clocaenog Forest Wind Farm Project

Case study 15382

Name of Client and Location: Innogy Renewables UK (Innogy)
Project Value: £120m
Duration of the Project: 18-24 Months and currently under construction. Electrical works June 2018 – September 2019
Services: Wind Farm Electrical Infrastructure, Balance of Plant (eBoP)
Market Sector: Renewable Energy
Powersystems Fact: Powersystems your high voltage specialist partners – Powersystems Renewable Energy team have connected 27% of all U.K. land based wind farm generation

Scope of work & major design considerations:

Clocaenog wind farm is located in Claocaenog Forest, South West of Denbigh and to the east of Brenig reservoir North Wales. The wind farm consists of twenty seven 3.6 MW Vestas Wind Turbines, each with a tip height of 145m. The 27 turbines will be erected within the working forest and managed by Natural Resources. This site was specifically designated by the Welsh Assembly Government as suitable for a large scale development of renewable energy.

Clocaenog wind farm will have an installed capacity of up to 96 megawatts. This is enough renewable energy for the equivalent domestic needs of up to 63,800 average UK households per year.

The Balance of Plant (eBoP) and electrical works are being undertaken by Powersystems UK Ltd. This is on behalf of Jones Bros Civil Engineering and on behalf of the wind farm developer Innogy Renewables.
Clocaenog Forest Wind Farm is a potential £120 million renewable energy project. And this construction could present significant opportunities for the local supply chain.

Clocaenog Wind Farm

The Clocaenog wind farm development:

Powersystems have been appointed to design, supply installation, testing and commission a 132kV grid connection. Consisting of the below elements;

  • 2 x 70MVA 132kV/33kV Grid Transformers and associated Circuit Breakers
  • Disconnectors / Earth Switches 132kV busbar network
  • Cabling to connect to 27 x 3.6MW Vestas Wind Turbines, located within the Clocaenog Forest
  • Within the Control Building duplicate 33kV Switchboards with circuits to feed six wind farm arrays
  • Bus-coupler arrangement to give running flexibility should one Grid Transformer be out of service
  • Plus the necessary Control and Protection Panels for the complete 132kV / 33kV systems, incorporating state of the art Point on Wave relays for the two 132kV Circuit Breakers
  • Compound and sub-station earth system installation and testing, including the adjacent SPEN Bryn Bach 132kV compound earthing
  • All necessary building fit-out works comprising Lighting and small power with intruder and fire alarm systems
  • Within the Clocaenog Forest itself, the installation of 33kV Power and Fibre Optic and Earth cabling works to all 27 x 3.6MW Wind Turbines
  • All wind farm cabling to connect into the Control Building

 Project Facts and Figures:

  • Number of turbines: 27
  • Wind turbine capacity: 3.6MW
  • Totalled Installed capacity: 96MW
  • Connection Voltage: 132kV
  • Size of site: 1,600ha
  • Energy for 63,800 households
  • Length of onsite 33kV cabling: 181.50km
The Clocaenog wind farm development

Clocaenog Wind Farm Project Timings:

Construction of Clocaenog Forest wind farm began in late March 2018 with mobilisation on site which involved preparing the ground for construction activity. Turbine component deliveries commenced in Jan 2019. Electrical work is planned to continue until September 2019.


Specification of equipment:

  • UK Grid Solutions Ltd – 2 x 145kV Dead Tank CB’s for POW switching
  • UK Grid Solutions Ltd – 4 x 145kV Double Break Disconnectors
  • Kelvin Power Structures – Complete set of 132kV Structures
  • Schneider Electric Ltd – 2 x 33kV WS Switchboards
  • Schneider Electric Ltd – 2 x 200kVA Auxiliary Earthing Transformers
  • Batt Cables plc – Wind Farm 33kV Cables
  • Premier Cables – Fibre Optic Cables
  • Arteche – 3 x 145kV Combined CT/VT
  • GE Grid Solutions – MiCOM P643 and MiCOM P14N relays for Grid Transformer Protection
  • Schneider Electric – P849 Relays for HV Scada Interface Panel
  • Visimax – SynchroTeq Plus Point on Wave Controllers
  • Cleveland Cables – 70mm2 earth cable for Wind Farm and Turbine Base Earthing
  • Centriforce – Tape Tile for Wind Farm Cabling
  • Earthmet – Cadweld+ equipment for Sub-Station / Compound and Wind Farm Earth connections. Also earth tape for compound / building
  • Cable Jointing Solutions – 33kV Cable joints
  • PE Systems Ltd – 2 x 110V Battery Charger Systems
  • R & M Electrical Group Ltd – Compound Lighting fittings and columns
  • GPS – LVAC Changeover Panel

How Powersystems have helped:

  • Electrical design
  • Switchgear supply, installation and commissioning
  • Transformer supply, installation and commissioning
  • Cables supply and installation
  • 132KV Busbar System and support structures design and install
  • Cable jointing
  • HV testing
  • SAP provision
  • Panel fabrication
  • Generator supply

The results

The work is still work in progress.  Powersystems are in the commissioning stage of 132kV compound. Turbines are still being delivered / erected.  Approx. 90% of the wind farm cabling is installed in trenches.

Environmental Benefits

Clocaenog wind farm will generate enough clean/green energy for the equivalent domestic needs of up to 63,800 average UK households . The project will play a significant role towards helping Wales to meet its renewable energy targets.

Economic Benefits

Announced in March 2021 RWE’s Clocaenog Forest onshore wind farm in North Wales has officially launched its £19million community fund and announced the first successful applicants from the surrounding communities.


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