A resilience-based recovery scheme for smart grid restoration following cyberattacks to substations

Abstract

The recent surge of interest towards deploying cyber systems in power grids exposes the resulted Smart Grids (SGs) to cyberattacks, and consequently resilience degradation. Among different possible remedies, i.e., prevention, mitigation, and recovery, developing a well-crafted recovery scheme following these cyberattacks can noticeably improve the system resilience. However, an appropriate resilience-based optimization problem with a metric to capture the system resilience during each step of recovery is needed to be solved and enhance it by the right decisions. To address such a concern, this paper proposes an innovative recovery framework based on a novel metric that captures the resilience posture of SGs against cyberattacks. The developed metric captures (i) Power-side Resilience (PsR) including load, available reserve capacity, available line capacity, and reliability, of which the last three are traditionally overlooked in resilience literature, and (ii) Cyber-side Resilience (CsR) considering the maximum possible implication of attacks on the power grid. PsR will calculate the physical side resilience based on immediate damage and CsR measure the cyber-side resilience e based on possible damage to the system. The SG is fully recovered from an attack when the proposed scheme brought back all the cyber and physical aspects to the proximity of the pre-disturbance conditions. For practical feasibility, we have incorporated different SG capabilities and limitations including generator Automatic Generation Control (AGC) capability and ramp rate, load variations during the recovery phase, transient stability, and multi-stage attacks. Moreover, an AC multi-island load flow is utilized to check the power balance, voltage boundaries, and transmission lines limitations in each recovery step. The proposed framework is evaluated on the 39-bus New England test system to demonstrate its effectiveness and also applied to the IEEE 30-bus test case to compare the results of the proposed approach with those of existing works. The comparisons show that the proposed approach can enhance the overall system resilience by 22% in comparison to existing works.