Gwynt y Môr is a 750-megawatt wind farm located 8 miles (13 kilometers) off the coast of North Wales. With 160 wind turbines, it is the second largest offshore wind farm in the world.
Mott MacDonald undertook a feasibility study for the electrical system, including studies of load flow, short circuits, fault ride-through, and grid connection. We developed several concept
designs for connecting wind farms to the grid.
Several high-voltage alternating current (HVAC) transmission voltage options and high-voltage direct current (HVDC) technologies were evaluated in terms of cost, maintenance, reliability, constructability, adaptability, and technology availability.
Mott MacDonald worked closely with HVDC technology suppliers to obtain data on active and reactive power control,
voltage control, and short circuit limitations.
Final commissioning for Gwynt y Môr was completed in June 2015. With an output of 1,950 gigawatt-hours per year, the wind farm can power around 400,000 homes.
Power transfer, transmission length, equipment layout, size, and weight were found to be the key parameters to determine where HVDC becomes cost-effective compared to HVAC systems.