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Concerns about the cybersecurity and resilience of power systems have heightened in electric utilities and regulatory agencies over the past decade mainly because of the unpredictable target, location and scale of cyberattacks and the potential severity of consequences. The cybersecurity of pilot protection is paramount in bulk power systems considering their prevalence and the crucial role they play in protecting critical assets and preventing large system disturbances and major blackouts. This paper investigates the resilience of pilot protection using a co-simulation platform based on OPAL-RT simulator and Riverbed Modeler. It is demonstrated that software-defined networking for operational technology (OT SDN) significantly improves the resilience of pilot protection to false data injection (FDI) attacks compared to traditional networks. Moreover, the resilience of OT SDN based pilot protection to denial of service (DoS) attack against the SDN controller is investigated both in the proactive and reactive modes of operation. The simulation results verified the resilience of OT SDN controller in OT SDN based pilot protection to DoS attacks in the proactive mode of operation. [ABSTRACT FROM AUTHOR]

Synchronization systems play a vital role in the day-to-day operation of power systems and their restoration after cascading failures. Hence, their resilience to cyberattacks is imperative. In this paper, we demonstrate that a well-planned false data injection attack against the synchronization system of a generator is capable of causing tripping subsequently leading to instability and blackout. We present an analytical framework behind the design and implementation of the proposed cyberattack. Moreover, we derive and discuss the conditions for which a cyberattack interfering with a synchronizing signal can be successful. Effective physical mitigation strategies are then proposed to improve the cyber-resilience of synchronization systems. The proposed cyberattack model and mitigation strategies are verified for a microgrid test system using an OPAL-RT real-time simulator. [ABSTRACT FROM AUTHOR]

In this paper, we consider a distributed energy storage system (ESS)-based control paradigm for transient stability of power systems. Utilizing a multi-agent control framework, we propose an effective virtual inertia measure for cyber-physical agents that includes both traditional synchronous generators and actuated ESSs. We derive the effective virtual inertia analytically for the case of general ESS-based control. We further consider the case of parametric feedback linearization control (PFL) as an application and investigate the proposed inertia measures after applying the PFL control. The utility of the proposed inertia measures is studied using the IEEE 68-bus test power system. Numerical results demonstrate the impact of storage limits, control scheme aggressiveness, and delay on the proposed inertia measures during a disturbance in the power system. [ABSTRACT FROM AUTHOR]

This work presents a new class of cyber-physical switching attacks that targets power transmission systems. The proposed approach relies on exciting inter-area oscillation modes in a coordinated manner to drive groups of system generators out of step. Our paradigm targets inter-area oscillations by switching a relatively small part (in the order of 2%) of the system load at a (low) frequency that resonates with one of the inter-area oscillation modes observed in the power system. The switching frequency of the targeted mode is chosen through measurement-based analysis of the frequency deviation at a select bus that is observable by the adversary. The inter-area switching attack is implemented as single-load switching and coordinated multi-load switching and is studied with a variety of switching signals. Numerical results show the potential and characteristics of the proposed switching exploitation when applied to the four-machine two-area power system and the Northeast Power Coordinating Council 68-bus system. [ABSTRACT FROM AUTHOR]

A novel framework for the distributed control is proposed in this paper for transient stability of smart power transmission systems in the face of disturbances. The proposed framework seamlessly integrates the traditional governor-based power control with energy storage system (ESS)-based controls. The design objectives also address practical challenges unaccounted for in former work, including limited ESS capacity and availability, and absent, delayed, or corrupt sensor measurements. The IEEE 68-bus test power system is used to demonstrate the merits of the control strategy in enhancing the transient stability of power systems. The results of this paper suggest that integrating different types of control can lead to an enhanced transient stabilization process in the face of different practical limitations. [ABSTRACT FROM AUTHOR]

Denial of service attacks and communication latency pose challenges for the operation of control systems within power systems. Specifically, excessive delay between sensors and controllers can substantially worsen the performance of distributed control schemes. In this paper, we propose a framework for delay-resilient cyber-physical control of smart grid systems for transient stability applications. The proposed control scheme adapts its structure depending on the value of the latency. As an example, we consider a parametric feedback linearization (PFL) control paradigm and make it “cyber-aware.” A delay-adaptive design that capitalizes on the features of PFL control is presented to enhance the time-delay tolerance of the power system. Depending on the information latency present in the smart grid, the parameters and the structure of the PFL controller are adapted accordingly to optimize performance. The improved resilience is demonstrated by applying the PFL controller to the New England 39-bus and WECC 9-bus test power systems following the occurrence of physical and cyber disturbances. Numerical results show that the proposed cyber-physical controller can tolerate substantial delays without noticeable performance degradation. [ABSTRACT FROM PUBLISHER]

Security of smart power systems is a sound concern as more cyber elements are added to the power grid. In this paper, we focus on cyber attacks that target data integrity in smart grid systems. We specifically investigate the impact of false data injection (FDI) attacks on distributed transient stability control schemes. As an example, we focus on the parametric feedback linearization (PFL) controller, and we derive closed-form expressions for the errors in rotors’ speed and angle as a result of cyber attacks on data integrity. Furthermore, we investigate adaptive control strategies to eliminate or minimize the impact of FDI attacks on system dynamics. The IEEE 68-bus test power system is used to numerically evaluate the impact of example attacks and to draw valuable insights. [ABSTRACT FROM PUBLISHER]

In this paper, we study a distributed control strategy that harnesses the highly granular data available in future power systems in order to improve system resilience to disturbances. Specifically, we investigate the role of external energy storage systems (ESSs) in stabilizing the dynamics of power systems during periods of disruption. We consider an information-rich multiagent framework and focus on ESS output control via linear feedback optimal (LFO) control to achieve transient stability. The LFO control scheme relies on receiving timely state information to actuate distributed ESSs in order to drive the synchronous generators to stability. We evaluate the performance of the LFO control on the 39-bus 10-generator New England test power system in the presence of ideal and nonideal conditions including communication latency, finite sampling rate, and sensor noise. The LFO controller is found to have a simple structure, be tunable, and to have fast response to achieving transient stability while being sensitive to information latency and data rate. [ABSTRACT FROM PUBLISHER]

A parametric controller is proposed for transient stability of synchronous generators after the occurrence of a disturbance in the power grid. The proposed controller based on feedback linearization control theory relies on receiving timely phasor measurement unit (PMU) information from selected parts of the power grid to employ fast acting flywheels that are situated near synchronous generators. The local storage devices aim to balance a swing equation model of the synchronous generator to drive the associated rotor speed to stability. The advantages of the proposed controller include that it is tunable and integrates well with existing governor controls in contrast to other forms of PMU-based control. Further, a comparison is drawn between the proposed controller and recently proposed nonlinear controllers for transient stabilization. Numerical results show the effectiveness and robustness of the proposed controller when applied to the 39-bus 10-generator New England power system. [ABSTRACT FROM PUBLISHER]

We propose a framework for the analysis of cyber switching attacks and control-based mitigation in cyber-enabled power systems. Our model of the switching attack is simple, only requiring knowledge of the sign of the local relative rotor speed, which may be estimated. The controller is modeled to be resource constrained, choosing to act only during select intervals of time. We make use of an iterated game-theoretic formulation to describe the interactions of the parties and its effect on system stability. Analytic results indicate the potential of the constrained controller to achieve transient stabilization over time using zero-determinant strategies. Numerical results of the New England 39-bus power system demonstrate the potential for such a controller to increase system resilience during cyber-attacks. [ABSTRACT FROM PUBLISHER]

Information and communication infrastructure will be extensively deployed to monitor and control electric power delivery components of today’s power grid. While these cyber elements enhance a utility’s ability to maintain physical stability, if a subset are compromised by adversaries, disruption may occur. In this paper, a novel framework based on the principles of differential games is proposed that demonstrates stealthy worst-case strategies for attackers to disrupt transient stability by leveraging control over distributed energy resources. We demonstrate that if the electric power utility is able to identify uncompromised components, countermeasures can exist that effectively reduce the impact of attack for a fixed time interval. Based on our results, we develop insights to construct safety margin recommendations for cyber-physical smart grid actuation elements that promote system resilience during a cyber attack. [ABSTRACT FROM PUBLISHER]

We present goal-seeking obstacle and collision evasion, an approach to resilient multicast routing for smart grid applications based on principles from robust flocking theory. We assert that analogies exist between the flocking principles of goal seeking, obstacle evasion, collision avoidance and behavioral transitions, and the routing goals of low latency, buffer overflow management, and adaptability in the presence of changing network conditions. Our multicast routing framework employs an underlying dynamical systems model convenient for integration with representations of power system dynamics to produce an overall cyber-physical smart grid description. Through simulations and comparisons with prior art we demonstrate how our approach provides insight on effective multicast routing principles to promote resilience in faulted power systems in the presence of congestion and denial-of-service attacks on communications infrastructure. [ABSTRACT FROM PUBLISHER]

Generator coherency identification is establishing itself as an important task to aid in the resistance of cascading failures within wide-area power systems and as a necessary preprocessing stage in real-time control for transient stability. Inspired by flocking behavior in nature, we propose a novel multiflock-based technique to identify generator coherence rapidly within a short observation window. Our measurement-based approach transforms generator data from the observation space to an information space, whereby the generator frequencies and phases characterize the movement and dynamics of boids within multiple flocks. Analysis of the boids’ trajectories enables the discrimination of multiple flocks corresponding to coherent generator clusters. We demonstrate the effectiveness of our technique to identify generator coherency rapidly while exhibiting robustness to environmental noise and cyber attack on the 39-bus New England test system and a modified IEEE 118-Bus test system. [ABSTRACT FROM PUBLISHER]

It is well known that information will play an important role in enhancing emerging smart grid system operation. Therefore, questions naturally arise as to when the increased data-dependence may be considered excessive. Two practical considerations emerge: 1) communications and computational overhead, in which redundant and irrelevant information acquisition and use results in heavy computational burden with limited performance return; and 2) increasing risks of power system disruption due to information delay from communication congestion or cyber attack. One strategy to improve smart grid resilience is to determine the appropriate degree of dependence on cyber information to balance performance with overhead and risk. In this paper, we present a hierarchical cyber-physical multiagent model of smart grid system operation based on flocking theory in the context of the transient stability problem. Through this model, we study strategies that harness a selective degree of cyber technology by leveraging physical couplings. Our formulation enables the identification of large-scale distributed control strategies for robust and resilient power grid operation. We demonstrate the potential performance improvements of our findings on the New England 39-bus power system for case studies involving a variety of system faults and communication delays. [ABSTRACT FROM PUBLISHER]