False Data Injection Attacks on Hybrid AC/HVDC Interconnected Systems With Virtual Inertia—Vulnerability, Impact and Detection

Abstract

Power systems are moving towards hybrid AC/DC grids with the integration of HVDC links, renewable resources and energy storage modules. The load frequency control (LFC) of tomorrow has to consider the complex interactions between these components. Meanwhile, more attention should be paid to cyber security concerns as the LFC loop highly depends on data communications which may be exposed to cyber attacks. In this regard, this article aims to analyze the false data injection (FDI) attacks on the AC/DC interconnected LFC system with inertia emulation and develop advanced diagnosis tools to reveal their occurrence. We build an optimization-based framework for the purpose of vulnerability analysis. Considering the attack impact on frequency stability, it is shown that the multi-area LFC system with parallel AC/DC links and emulated inertia by storage devices is more vulnerable to FDI attacks, compared to the one without inertia emulation and the normal AC system. We then propose a detection approach to detect and isolate each FDI intrusion with a sufficient fast response, and even recover the attack value. In addition to theoretical results, the effectiveness of the proposed method is validated through simulations on the two-area AC/DC interconnected LFC system with inertia emulation capabilities. INDEX TERMS AC/DC system, load frequency control, inertia emulation, false data injection attacks

Effects of Cyber Attacks on AC and High-Voltage DC Interconnected Power Systems with Emulated Inertia

“…Then next we study FDI attacks on the test LFC system in the hybrid AC/DC grid with virtual inertia. We extend our previous work [32] to include both stationary and dynamic FDI attacks in this article. Particularly, we show a specific type of dynamic FDI attack that can remain stealthy with respect to an arbitrary anomaly detector, while in the mean time cause severe damages to system frequency stability.…”

“…The work in [31] has interpreted the effects of FDI attacks on the LFC of a low-inertia power system. Our recent work in [32] aims to propose a comprehensive framework for vulnerability and impact analysis of stationary FDI attacks on the hybrid AC/DC grid. To conclude, research efforts are still needed to evaluate the effects of different types of data integrity and availability attacks on the LFC system with new elements of HVDC link and also ESS for virtual inertia.…”

“…Two major types of data availability and integrity attacks-DoS and FDI attacks-are introduced and explored. The FDI attack scenario has been introduced in our previous work [32], where only the stationary FDI attack is considered. In this article, we move a step forward to include the dynamic (time-variant) FDI attack.…”

“…The selection of control gain J em i is based on an iterating tuning approach where the frequency deviations are minimized; we refer to the work in [34] for details. Considering that the derivative control loop could be sensitive to the noise, one may add a low-pass filter to the model to eliminate the effects of noise [32] (here we consider the filter's effects through the time constant T ESS i ). The storage part of ESS will remain charged during normal operation, and it starts to help the system once contingencies occur.…”

“…The attack values which reflect the attack targets on impact and undetectability are taken from the set F := { f ∈ R n f : b min ≤ F f f ≤ b max } where the vectors b min , b max ∈ R n b and the matrix F f ∈ R n b ×n f are scenario-specific and should be taken based on the criterion reflected in different national grid codes. For instance, to be disruptive of attack impact, the (absolute) MFD value should reach 0.8 Hz, as a possible load shedding scheme could be triggered when the frequency decreases to 59.2 Hz; we refer to our previous work in [32] for a detailed discussion on the selections of b min , b max and F f . In (31), f (i) denotes the i-th FDI on the measurement that the attacker has already been able to compromise; this constraint is to make (31) feasible [37].…”