Wind farm power systems studies, Ireland

TNEI supported multiple involved parties, including the developer, contractor, manufacturer and TSO EirGrid, through power system studies for Galway 110kV wind farm cluster and Knockranny substation in Ireland. Galway cluster (Uggool 66MW and Cloosh 108MW) is fed from Knockranny switching substation which is connected to the transmission grid via more than 30km of 110kV cable.

As part of this project, TNEI provided the following services:

  • Design studies, involving multiple turbines to help the developer choose the optimal WTG. Load flow studies to determine losses, thermal ratings and any further reactive compensation requirements.
  • Fault level study to determine the minimum switchgear ratings.
  • Flicker, voltage step change and energisation inrush studies to ascertain compliance with TSO requirements.
  • Comprehensive harmonic studies to assess compliance based on TSO impedance loci (using over 1000 points per area) and site-specific incremental limits.
  • Transient stability studies, such as fault-ride through and dynamic voltage control studies (including parameter modifications) to verify compliance against the Grid Code requirements.
  • Detailed 110kV harmonic filter design studies for the TSO EirGrid to manage low order harmonic background amplification across the wider network due to the long cables. Full 30MVAr C-type harmonic filter specification and individual component tolerances were established.
  • A complete set of insulation coordination studies in PSCAD to determine whether the wind farm and the filter components were adequately rated for transient events. Studies established the surge arrestor characteristics, taking into account switching, temporary and lightning overvoltages as well as the response during internal and external faults.

TNEI carried out system studies at wind farm and transmission level to optimise the reactive compensation, harmonic filter solution and insulation coordination issues, leading to the successful design of the largest onshore wind farm in Ireland.