Vulnerability Assessment of AC State Estimation With Respect to False Data Injection Cyber-Attacks

Abstract

Abstract-This paper introduces new analytical techniques for performing vulnerability analysis of state estimation when it is subject to a hidden false data injection cyber-attack on a power grid's SCADA system. Specifically, we consider ac state estimation and describe how the physical properties of the system can be used as an advantage in protecting the power system from such an attack. We present an algorithm based on graph theory which allows determining how many and which measurement signals an attacker will attack in order to minimize his efforts in keeping the attack hidden from bad data detection. This provides guidance on which measurements are vulnerable and need increased protection. Hence, this paper provides insights into the vulnerabilities but also the inherent strengths provided by ac state estimation and network topology features such as buses without power injections.

Extended Distributed State Estimation: A Detection Method against Tolerable False Data Injection Attacks in Smart Grids

“…A high threshold may lead to a high false alarm rate. According to [4], p = 95% is an empirical value.…”

“…In this case, the hacker tries to reduce the measurement of active power on bus 5 . Then, a TFDI attack is launched and 60.96 MW of power load is moved from bus 5 to bus 4 . According to the current tariff published by the Pacific Gas & Electric Corporation [20], the electricity price is 0.18590$/kW h. If this attack lasts for one day, customers on bus 5 may see their costs unjustly lowered by $272,871.…”

“…The result shows that if the attack illustrated in Figure 1 is launched, the loads of bus 4 and bus 5 and the power flow on the line will change. The value of injected power on bus 5 is negative after the modification.…”

“…The value of injected power on bus 5 is negative after the modification. Thus bus 5 pretends to feed energy back to the power grid, and will mislead the control center to reduce the generation output on bus 1 , bus 2 and bus 3 and increase the generation output on bus 8 to meet the increased demand on bus 4 . Output of each generator will be adjusted to pursue the lowest generation cost [24].…”

“…While relatively effective against random noises, these detectors lack the ability to detect specialized and highly structured false data that conforms to the network topology and some particular physical laws. Recent works [4][5][6][7][8][9][10] have demonstrated that an adversary, armed with knowledge about the network's configuration, can successfully construct undetectable FDI attacks on SE avoiding detection. However, there are still some obstacles to launch such attacks.…”