Power utilities implement cyber-security defence with a philosophy of defence in-depth. Firewall and air-gapped systems are widely used to harden cybersecurity defence of critical power system infrastructure. However, cyber-attack, such as global positioning system (GPS) spoofing, that can compromise the air-gap system has not been investigated thoroughly. As a geographically dispersed cyber-physical system, the power system relies heavily on the GPS to keep time synchronisation of different parts with high precision. GPS spoofing-based time synchronisation attack (TSA) could induce disorder i...
