Saturation Defense Method of a Power Cyber-physical System Based on Active Cut Set

Several large-scale blackouts have shown that coordinated attacks on the power cyber-physical system can lead to the rapid spread of grid failures and even system collapse. Focusing on the emergency in which system faults cannot be eliminated in a short time and has the trend of rapid diffusion, this paper adopts the idea of saturation defense and proposes a novel method of saturation defense method based on an active cut set. The algorithm employs the improved weighted GN splitting algorithm to search for the feasible domain of cyber cut surfaces. Then by taking the constraint of generators coherence, power balance, and the minimum active power flow impact, a feasible scheme for partition is optimized. Therefore, while ensuring the minimum loss of cyber performance and satisfying the stability constraints of the physical system, a unified cyber and physical active cut surface is found. It actively splits threat sub-area with the minimum performance loss, prevents the expansion of attack damage, and maintains the stable operation of security main area. Simulation studies with the improved IEEE-39 bus system show that the proposed method has a strong capability in attack blocking and an advantage in low loss of load probability under different attack intensities.