Connecting at 33 kV onto a Super Grid Transformer tertiary winding is unusual and brings its own complications. The tertiary is electrically very close to the transmission network which makes the system stiff and the protection coordination more sensitive than a typical distribution connection, while still being treated as a Grid Code site for compliance purposes.

Aurora delivered the full Grid Code compliance package, with RMS and EMT simulations to GC0141 and PC.A.9, P28 (RVC/SVC), G5.5 harmonics, TGN 288E insulation coordination and DRC schedules. The protection coordination study was carried out in detail because the proximity to the SGT made conventional rule-of-thumb settings unsuitable.