Assessment of Security Index for SCADA Systems in Smart Grids

Abstract

This paper focuses on the security of state estimation in supervisory control and data acquisition (SCADA) system in smart grids. The security index has been wildly studied to evaluate the vulnerability of SCADA systems under various types of cyber attacks, e.g., the false data injection (FDI) attack and distributed denial of service (DDoS) attack. However, it is shown that the calculation of security index is an NP-hard problem. Therefore, we propose an algebraic polynomial-time algorithm to calculate the security indices iteratively based on the orthogonal projection technique. Since existing modeling methods of security index only consider the attack overhead, without considering the impact of cyber attacks on the system performance, a novel hybrid security index is constructed. In the hybrid security index, the overheads of FDI attacks, DDoS attacks, and the impact of attack on the estimation error are considered simultaneously. Numerical results show that the protection of some critical measurements can enhance the overall security of SCADA systems.