Dorenell Wind Farm

Case study 15274

Name of Client and Location: Dorenell Windfarm, Glenfiddich Estate, A941 (South of Dufftown), Moray, AB55 4DT
Duration of the Project: 20 months
Services: Electrical Infrastructure, Grid Connection, Sub-Station
Market Sector: Renewable Energy
Powersystems Fact: Powersystems your high voltage specialist partners – Powersystems Renewable Energy team have connected 24% of all U.K. land based wind farm generation

Scope of work and major design considerations:

In May 2008 Infinergy Ltd applied to the Scottish Government, for planning permission for the construction of Dorenell Wind Farm. The wind farm was to occupy an area of land approximately 7km by 5km on the Glendfiddich Estate. This is approximately 8km South East of Dufftown and 2.2km from the boundary of the Cairngorms National Park.

The wind farm development:

  • Construction of 59 turbine bases and crane pads
  • Construction of 34km of new site roads, upgrading of 2.2km of forestry track and 5.3km of existing site tracks
  • Construction of a substation compound with a footprint of approximately 150m X 75m comprising 2 substation buildings
  • Construction of approximately 40km of cable trenches
  • Installation of 59 3MW turbines with a maximum tip height of 126m

    Generating power for homes

    The 177MW wind farm will generate sufficient energy to power approximately 109,112 homes. In addition, will also contribute to the Scottish Governments target; to ensure that 100% demand for Scotland’s electricity is to come from renewable energy sources by 2020.

    £8m to local community fund

    This project saw the installation of 59 Vestas V90 3.0MW turbines. With a tower height of 81m and hub diameter of 90m as well as a planned operating life of 25 years. EDF have committed to contribute over £8m, to the local community fund. This is over the life span of the windfarm, in addition to a range of improvements to regenerate the Cabrach area and strengthen tourism.

    Meeting household electricity needs

    The 59 3MW turbines generate at 33kV. These are arranged over 7 Arrays, which feed into the wind farm substation. The voltage is then increased to 132kV by 2 120MVA 33/132kV transformers, prior to connecting to the SHETL 132kV distribution network.

    Dorenell wind farm is connected to the SHETL distribution network, via 2 132kV overhead lines, approximately 22km in length, which  additionally connect to Blackhillock Primary substation on the outskirts of Keith, Moray.

    Dorenell Wind Farm Blue Sky

    Project Facts and Figures:

    • Number of turbines: 59
    • Wind turbine capacity: 3 MW
    • Totalled Installed capacity: 177MW
    • Connection Voltage: 132kV
    • Connection to Grid:  SHETL distribution network at Blackhillock primary.
    • Size of site: 35km²
    • Energy for 109,112 households *
    • Length of onsite access tracks: 42 km
    • Length of onsite 33kV cabling:240km

    *This figure is based on site specific data, using the following calculation: Maximum installed capacity of the Wind Farm (177MW). Then multiplied by the number of hours in a year (8766), multiplied by the output capacity of the wind farm as a percentage (30%) [Renewable UK]. Then divided by the amount of energy used, by each UK home on average per year (4,266 kWh) [DECC].

    Wind Farm project timings:

    Planning permission for the development was granted, after public consultation, by the Scottish Government in December 2011. In November 2015 the Dorenell wind farm development was acquired by EDF Renewables. EDF Renewables operate 35 onshore and offshore wind farms throughout the UK with a combined output of over 965MW.

    Onsite construction of Dorenell wind farm commenced in April 2017. The 132kV electrical connection to the site was energised in August 2018. The first turbines were erected and began generating in August 2018. The final 59th turbine was constructed in December 2018. The farm has been fully operational since 20 December 2018. All construction works were completed by the 31 December 2018.

    Dorenell Wind Farm Blade Transportation

    What the client wanted:

    EDF Renewables operates in more than 20 countries around the world. EDF develop, construct and operate wind farms, solar and battery storage projects, and have more than 25 years’ experience in delivering renewable energy generation. EDF Renewables is a joint venture between EDF Renewables Group (EDF’s global renewable business) and EDF Energy (EDF’s UK generation business).

    It is focused on the development, construction and operation of onshore and offshore wind farms. They already operate more than 965MW of wind farms within the UK, additionally, with a further 2.0GW consented or in planning and development.

    EDF are the UK’s largest producer of low-carbon electricity, the biggest supplier of electricity by volume in Great Britain and the largest supplier to British businesses. They form part of the EDF energy group and have over 13,000 employees within the UK.

    How Powersystems helped:

    Powersystems UK were appointed as the wind farm Balance of Plant (eBoP) contractor. With responsibility for the design, build, commissioning and energisation of the entire wind farm electrical infrastructure works. This included from the 132kV connection to the DNO. And then through to the final electrical and fibre optic terminations to the Vestas V90 turbines.

    We worked with EDF engineers to fine tune the employer’s concept designs and produce detailed general arrangements. As well as technical designs for all aspects of the project, after that, these were then taken through to construction.


    Dorenell Wind Farm Rear of Switchgear

    The list of responsibilities as the main electrical contractor are extensive for such a large project but can be summarised as follows:

    Design Works
    • 132kV Compound – produce 132kV compound equipment general arrangement drawings, produce 132kV equipment plinth details, provide 132kV support structures designs & 132kV overhead busbar layouts
    • Wind Farm Substation 33kV Switchgear – specification of 33kV switchgear and full design specifications for control and protection systems
    • Control Building – provision of equipment GA’s, small power & lighting layouts, fire and security layouts
    • STATCOM Compound – produce general arrangement drawings, equipment plinths designs, cable containment / ducting system layouts
    • 33kV Cable Arrays – design of the cable trenches (with respect to the track layouts), Array SLD’s, cable sizing and loss calculations, trench cross sections
    • 132kV and 33kV Earthing System Design – produce full earthing design studies (based on soil resistivity readings taken from site), produce earthing designs for the turbine foundations and substation compound
    • Protection Systems – design of the 132 and 33kV protection equipment schemes including the design of protection SLD’s, relay panels & schemes, protection coordination studies and relay settings / logic files
    • Control Cabling – design of all small power and equipment control wiring
    Installation Works:
    • 132kV Compound – installation of 132kV through wall bushings, 132kV busbar support structures and busbars, 132kv surge arrestors, 33kV AIS support structures and busbars, 33kV cable installation, control cabling between all 132kV equipment and SCADA / protection panels
    • STATCOM Compound – installation of 2 hybrid STATCOM systems comprising 2 STATCOMiInverter containers, 4 off 33/0.4kV 5MVA transformers, 4 off 12MVAr 33kV switched capacitors including offloading of the main components, 33Kv cable installation, control cabling between all components and 33kV switchgear, STATCOM control panels, SCADA panels
    • 33kV Switchgear – installation of 19 panel Schneider WS 33kV 2500A 31.5kA switchgear, installation of control cabling between switchgear and ancillary equipment / SCADA panels
    • Windfarm Ancilliary Equipment – installation of 132kV protection panels, AVR panels, Switchgear remote indication / operating panels, 110V battery chargers, auto changeover panels, STATCOM control panels, control cabling between substation equipment and control panels
    • Wind Farm Control Building – installation of small power & lighting, fire and security systems.
    • 33kV Cabling – installation of approximately 236km of 800/400/240mm Aluminium 33kV cables between the main substation and the 7 turbine arrays
    • Fibre Optic Infrastructure – installation, splicing and OTDR testing of 12km of 32/16F pre-ducted fibre optic cable between the man substation and 7 turbine arrays
    • HV Jointing – installation of 270 33kV single core straight joints, 51 Pfisterer 33kV Size 3XL terminations, 420 33kV bolted T connectors, 18 33kV outdoor terminations
    • Earthing – installation of 59 turbine base earth mats, 50km of horizontal 50mm bare coper earth conductor (installed with array cables), installation of the main substation earth mat comprising of approximately 6km of 50x4mm copper earth tape
    Dorenell Wind Fram Renewable Technology
    Commissioning Works:
    • 132kV Compound – Tan Delta Testing of the 132/33kV transformers and 132kV overhead busbars, functional testing of the 132/33kV Main transformers control systems, cooling systems, tap changers & trip / alarm testing to protection & SCADA panels.
    • Functional testing of the ABB PASS 132kV circuit breakers including CT testing, VT ratio testing, Interlocking and Trip / Alarm testing to Protection & SCADA panels
    • VLF testing of the 33kV cables between the main transformers and 33kV switchgear. Ductor testing of all overhead busbar connections. Ductor testing of all earth mat connections. Commissioning of Transformer bund pumps
    • 33kV switchgear – Full commissioning of the 33kV switchgear including connections / signals to external equipment & SCADA including AC pressure tests, ductor testing, VT and CT ratios, functional testing (including interlocking), relay testing, 61850 relay communications to SCADA
    • Protection / AVR panels – Full commissioning of the 132kV Transformer protection panels and voltage regulation panels including protection relay functional testing, secondary injection and 61850 interface testing to SCADA
    • Wind Farm Control Building – testing of the small power & lighting, fire & security systems
    • 33kV Cable Arrays – Sheath Testing, IR / VLF testing of all 33kV Array Cables to all turbines
    • FO Infrastructure – OTDR testing of the fibre optic infrastructure to all turbines
    • Earth Testing – Soil Resistivity and earth Resistance testing of the Main Substation compound and the 59 turbine bases followed by an overall site earth resistance test
    Energisation Works:
    • 132kV SAP to attend site meetings with the client and Scottish and Southern Electricity Networks (SSEN) Distribution Network Operator (DNO) to discuss and finalise the energisation program of works and produce energisation plans and switching schedules

    Watch a short film on the Dorenell Wind Farm Connection

    • Provision of 132kV SAP to attend site to provide supervision and undertake pre-energisation inspections and issue safety documentation prior to first energisation of the site. SAP attendance for energisation of the 132/33kV equipment
    •  33kV SAP for pre-energisation inspections and energisation / commissioning of the 33kV STATCOM components. Undertake HV switching / issue safety documentation as required by the STATCOM supplier
    • Supplying 33kV SAP for testing and energisation of the Array cables, pre-energisation inspections of the turbine 33kV switchgear and transformers and for energisation of the turbines
    • Provision of 132/33kV SAP to support the client and turbine supplier with HV switching works as required during the commissioning phase of the turbines through to handover to the clients appointed HV operations team

    The results:

    Dorenell Wind Farm was completed in December 2018, following a very short construction period for a project of its given size and complexity. The project was completed in line with the clients construction program with no delays.

    In conclusion the project is the EDF Renewables largest onshore wind farm constructed to date and signals a continued working partnership with Powersystems UK. 

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