Date of Completion: July 2017 to April 2019

OVERVIEW

Ballycumber Wind Farm (WF) is located near Tinahealy, Co. Wicklow. The WF includes six Siemens SWT 101 3.2MW Wind Energy Converters (WEC’S) with a maximum installed capacity of 19.2MW and a maximum export capacity of 18MW. Each WEC is capable of a maximum output of 3.2MW via a turbine transformer. The WTGs are connected at 38kV to the ESBN distribution network at the point of connection via the grid transformer located at the WF substation (Ballycumber). Ballycumber WF was contestably built Substation.

SCOPE OF SUPPLY OF CONTESTABLE WORKS

Mainline completed the substation contestable works in accordance with the ESBN functional specifications, designs and material specifications and drawings issued by the Utility Company. The Contestable Works consisted of the design, supply, installation, testing and pre-commissioning of the following equipment:

38kV external substation works, including:

• • Incoming cable terminations and support structures
  • 38kV surge arrestors
  • 38kV disconnectors
  • 38kV circuit breaker
  • Combined revenue metering CT/VT’s
  • CT’s for the protection and metering systems
  • Post insulators, busbars, and connectors to complete the substation and connection to the WF substation side
  • Lightning protection system in accordance with the design requirements
  • Telecommunications equipment and links

38kV internal substation works, including:

• • • LV AC and DC auxiliary power supplies and distribution
    • Protection and control panels, including EGIP protection relays
    • Communications panels, RTU’s etc.

• All LV, control and communications wiring
• Earthing system and connections to all equipment, fencing, gates, and building structures
• Internal and external building services
• Testing and pre-commissioning of the completed works to Utility Company requirements for handover to the commissioning engineer, and detailed liaison with ESBN in this regard.

SCOPE OF SUPPLY OF WIND FARM ELECTRICAL WORKS

Mainline Power were responsible for all electrical works between the WF grid connection point and the WTG 20kV switchgear including the electrical works associated with the wind farm collector cabling system. Mainline coordinated with ESBN, and the Employer as necessary, to ensure the works were designed and installed to the appropriate standards.

The WTG transformers were installed by the WTG Supplier under a separate contract. The termination points were defined as the WTG 20kV switchgear terminals. Mainline provided the power cable termination kits as per the WTG supplier specification and terminated and tested the same.

The Wind Farm Electrical Works consisted of the design, supply, installation, testing and commissioning of the following:

• 38/20kV – 20/25MVA  – ONAF on load tap changer grid transformer including the tap changer control panel, remote control panel (AVR), differential protection relay and associated CTs
• 20kV external substation works, including:
  • Neutral earthing resistor (NER) with CT’s for REF and SBEF protection
  • 20kV/0.4kV auxiliary services transformer with primary fusing and secondary MCCB’s
• 20kV substation switchboard including:
  • 1 no. incoming circuit breaker complete with automatic reclose facility, surge arresters and incoming cable earth switch
  • Wind farm radial circuit breakers – each with wind farm cable earth switch
  • All protection and metering class CT’s and VT’s, including provision of current and voltage to WTG supplier SCADA system
  • Overcurrent and earth fault protection on all circuit breakers
• HV cabling within the substation
  • 38kV Cabling between IPP and ESBN Substation
  • 20kV NER Cabling
  • 20kV HoT Cabling
  • 20kV Cabling between Switchgear and Grid Transformer
• Mimic, protection and control panels for remote monitoring and operation of the WF electrical system including:
  • Grid transformer voltage control (AVR) and differential/restricted earth fault protection
  • ION 7650 Power Quality meter and associated software for remote interrogation
  • Mimic and remote control, indication and instrumentation for the 38/MV system, including passive graphic of the Utility Company 38kV side with CB open/closed indication
• Suitable DC power supply system with 24-hour battery and dual battery charger for the WF substation equipment
• LV AC distribution board fitted with manual changeover facilities and an external 3 phase plug/socket for the connection of a temporary diesel generator set on loss of supply from the auxiliary transformer
• All LV, control and communications cabling
• Earthing system for the entire wind farm site
• Lightning protection system for the WF substation and each WTG’s as required by the design study
• Testing and commissioning of the complete electrical systems and work
• Energisation of the works, including all liaising with the Utility Company prior to energisation, snagging, installing safe systems work, certification of equipment and provision of the Declaration of Fitness (DOF), as required by the Utility Company
• Operation of the works until takeover
• Provision of a full telecommunications solution at the wind farm in accordance with the requirements included in the ESB functional specification, the Employers Requirements and the relevant codes and standards for wind farms connecting to the distribution network

WIND FARM ELECTRICAL WORKS

Mainline were responsible for the following in relation to the wind farm site:

• The Design, Supply, Installation, Testing and Commissioning of the 20kV wind farm collector cabling including designing the ducting and associated trenching within the wind farm site.
• 20kV Cable Jointing and Terminating in the WTG’s and Substation including End to End testing. Testing included the following
• After installation and termination, but prior to connection to the respective items of equipment, Mainline performed a 5kV Megger insulation resistance test between conductors and screen on each length of cable for the duration of 1 minute and recorded all results including confirmation of cable phasing. Resistance values greater than 10GOhm were deemed acceptable.
• Cable sheath tests were carried out in accordance IEC 60229. Where cables were supplied with an outer semi-conductive coating, sheath tests were be carried out on all cable drums prior to installation.
• After all 20kV cables were terminated, Mainline performed Very Low Frequency (VLF) tests between conductors and screens (which were all earthed) for 60 minutes at a voltage of 3 times phase voltage and 0.1Hz on the complete 20kV system including the wind farm site installations for each part of the wind farm. Following each high voltage test, verification took place to make sure that all equipment and cables were adequately discharged to safe voltage levels.
• The Design, Supply, Installation, Testing and Commissioning of the wind farm earthing system wind farm site.
• The Design, Supply, Installation, Testing and Commissioning of the internal Fibre Optic communication cabling within the wind farm site.

38KV GRID CONNECTION ELECTRICAL WORKS

Mainline were responsible for the following in relation to the 38kV Grid Connection:

• The Design, Supply, Installation, Testing and Pre-Commissioning of the 38kV Grid connection cabling including designing the ducting and associated trenching within the wind farm site.
• 38kV Cable Jointing and Terminating along the Grid Route including End to End testing.
• The Gird Route was 25km in length and consisted of 24 Joint Bays in total. This compromised of:
  • 12 Straight Through Joints
  • 12 Sheath Break Joints
  • Terminations in Kilmagig 38kV Substation
  • Terminations in Mangans 38kV Substation
• The Supply, Installation, Testing and Commissioning of the 38kV Fiber Optic communication cabling along the Grid Route. This included:
• • 8 Splice Joints
  • OTDR Testing End to End Testing

CBOP Works (Substation / Wind Farm /Grid Connection and Delivery route)

The Civil Balance of Plant (CBoP) Contract consisted of the design, supply and construction, both temporary and permanent of:

• Reinstatement of Turbine Delivery Route Temporary Accommodation Works on public roads / third party lands,
• Final surfacing on sections of public road along Turbine Delivery Route (Rathshanmore South),
• Final grading (Post Turbine Delivery) of internal wind farm roads,
• Completion of all minor civil works on site (including but not confined to Substation & Compound and Turbine access),
• Completion of all drainage associated with the Works within the Site,
• Completion of site fencing including site entrance works & permanent access barrier,
• Completion of Wind Farm 20kV internal circuit installation and testing,
• Completion of 38kV grid connection cable trenching, ducting and cabling (Site Sub-station to Kilmagig Sub-station), testing, energisation and all associated permanent road reinstatement.