Sanquhar II Wind Farm — Grid Code Compliance
250 MW Onshore Wind Farm, 132 kV SPT connection
The challenge
Sanquhar II is one of the largest onshore wind farm developments in the UK, at a scale that attracted close interest from both SPT and NESO. The site was unusually challenging because of the low system fault level, which created potential P28 compliance issues for voltage trips and array transformer energisation. A detailed insulation coordination study was also required to assess switching and lightning overvoltages and optimise surge arrester selection and location.
What Aurora did
We developed detailed DIgSILENT PowerFactory and PSCAD models of the wind farm and used them to support the Grid Code compliance evidence, including RMS and EMT studies. The low fault level made P28 RVC/SVC assessment particularly important, especially for site voltage trips and transformer energisation cases.
Alongside the compliance package, Aurora delivered G5.5 harmonics, TGN 288E insulation coordination, DRC schedules, protection coordination and a detailed CDEGS earthing study for the 132 kV and 33 kV infrastructure.
We also completed a detailed earthing study covering the 132 kV substation, the associated 33 kV substation and over 44 individual wind turbine locations. This included site EPR, touch and step voltages for local and transfer faults, and the full site layout earthing drawing for construction.