There is serial compensation capacitor on the transmission lines which connects the north part of National Grid System and the south part of Scottish Power Transmission System. For preventing the risk of sub-synchronous oscillation which leads to unit damage by shaft torsional vibration, SIFANG supplied sub-synchronous oscillation protection systems on synchronous generating units integrating GPS Clock Synchronizer at Hunterston B/Torness Nuclear Generating Station. Besides providing the required protection systems, SIFANG also supplied the design & engineering, testing, commissioning, training, S-N curve calculation and project management for this project.