This study proposes an active defense strategy against denial-of-service (DoS) attacks to address the secure event-triggered control of multiarea load frequency control (LFC) systems. A novel interval secure event-triggered mechanism (ISETM) is introduced, integrating event-triggered control with cybersecurity mechanisms under the software defined network (SDN) framework. ISETM generates not only a triggering instant but also a secure triggering interval (STI) simultaneously. The STI sent to the SDN control plane is an estimation time interval generated by the Taylor expansion and model-based prediction method. During this interval, the SDN control plane programs OpenFlow switches to filter attack traffics, ensuring delayed but secure triggering transmission. Under ISETM conditions represented by two systems of inequalities, a multiarea LFC system is modeled as a delay system incorporating a triggering error based on the Taylor expansion. To achieve performance of the established LFC system, a criterion is derived using the Lyapunov-Krasovskii functional method. A codesign approach is provided to solve the proposed ISETM control (ISETC) gains through linear matrix inequality (LMI) techniques. Finally, simulations validate the effectiveness and advantages of our proposed method.

An indirect–direct secure control (IDSC) method is proposed for load frequency control (LFC) of multi-area power system under false data injection attacks. In the indirect secure control, based on the inherent local security of primary frequency control, an estimation system in power plant is established to reconstruct LFC commands. In the direct secure control, PI-based LFC scheme is adopted with a new robust performance index. Thus, a complementary secure strategy realized by IDSC is developed from combining resilience to cyber-physical disturbances and elimination of attack intrusion. We adopt mixed$H_{\infty }/H_{2}$control method to formulate and design interconnected IDSC and decentralized IDSC. Simulations of the three-area power systems are carried out to verify the validness of our proposed IDSC method.

Secure frequency control of multi-area hybrid power systems with wind power is a research problem involving active defense, vulnerability, and resilience. Considering the scenario that Denial-of-Service (DoS) attack intrude into the control channels of thermal power and wind farm, the hybrid power system is modeled by a switched system with four subsystems. Then, the exponential stability of hybrid power system is studied under arbitrary DoS attack. An active defense scheme is proposed to design switched control gains by Lie algebra method achieved by a distributed consensus method. Furthermore, following the resulted exponential stability, the load disturbance attenuant performance of frequency control is studied by the proposed concepts of vulnerability point and resilience point. Under a class of event-DoS attack model, the estimation method of vulnerability point and resilience point is given. Finally, simulations of a three-area hybrid power system and NE39bus test system are carried out to verify our theories.

Resilient distributed coordination control is studied on multiarea power systems with low inertia under hybrid attacks, including denial-of-service (DoS) attack and deception attack. The communication among various areas under the DoS attack is deteriorated to switching residual topologies whose time characteristic is modeled by model-dependent average dwell time (MDADT). Deception attack with malicious strategy targeting at negative feedback control is modeled by a sign function. To obtain resilience performance of the power system under low inertia and hybrid attacks, resilient distributed scheme combining load-frequency control (LFC) with virtual inertia control (VIC) is proposed. Then, resilient frequency control problem of the studied power system is converted to$H_{\infty }$control of the switched nonlinear system. By employing the Lyapunov stability theory and switched system method, the resilient conditions are given by the lower bound of the average dwell time of each residual topology and the upper bound of deception attacks. Furthermore, a linear matrix inequality (LMI) technique is used to design the distributed resilient control gains of the LFC-VIC scheme. Finally, a simulation of four-area power systems is carried out to verify the validness of our theory.

This article is concerned with the problem of observer-based dynamic event-triggered control for a networked control system (NCS) under a class of power-constrained denial-of-service (DoS) attacks that aim at impeding the network communication from time to time. First, by carefully modeling such DoS attacks as aperiodic pulse-width-modulated (PWM) jamming signals, a switching observer, adapting to the DoS attacks, is delicately constructed to deal with the unavailability of full-state information. Second, to economize the limited bandwidth resources, a dynamic event-triggered communication scheme is designed under the aperiodic DoS jamming attacks, whose duration and frequency are assumed to be restricted. Third, a switching system model with artificial state delay is formulated, which characterizes the effects of the aperiodic DoS attacks and event-triggered communication scheme in a unified framework. Then, the asymptotic stability analysis and controller/observer synthesis conditions of the resulting switching system are obtained by using a piecewise Lyapunov-Krasovskii functional approach. Furthermore, a co-design method of the dynamic triggering parameters, controller, and observer gains is presented. Finally, an example is employed to verify the effectiveness of the obtained results.

This note is concerned with bandwidth allocation-based switched dynamic triggering control under DoS attacks and time delay. To prevent DoS attacks from causing open-loop unstable operation of the system with single-channel transmission, we present a primary-redundancy (PR) communication structure on the basis of limited bandwidth allocation; the correlation of communication delay bound between PR channels is introduced. To save the limited bandwidth, we propose a dynamic the event-triggered mechanism (DETM). Then, a switched delay system model is established to describe system dynamic driven by primary channel control, redundancy channel control, and unstable operation under DoS attacks. Further, by using the convex combination method, a switching law for PR channel is designed with the aim of keeping the concealment of the redundancy channel. With the switching law, a criterion of exponential stability is obtained by using piecewise Lyapunov-Krasovskii functional method. A co-design method is proposed to obtain feedback control gains, DETM parameters and switching law parameters. Finally, two simulation examples are illustrated to verify the validness of our proposed method.

This paper focuses on the resilient H∞filter design for event-triggered networked systems subject to nonperiodic denial-of-service (DoS) jamming attacks. In this paper, a new resilient event-triggered transmission strategy is first proposed to improve the efficiency of network resource utilization while counteracting the nonperiodic DoS jamming attacks. Then, by using a time-delay approach, the filtering error system is modeled as a switched system, which characterizes the effects of the event-triggering scheme and nonperiodic DoS jamming attacks simultaneously. Based on the established model, by using the piecewise Lyapunov-Krasovskii functional method, linear matrix inequality (LMI)-based sufficient conditions are formulated to achieve the globally exponential stability as well as the weighted H∞performance of the resulting switched system under the DoS jamming attacks. Consequently, the co-design method for the desired filter parameters and event-triggering parameters can be formulated provided that the above LMIs are feasible. Finally, the effectiveness of the proposed method is demonstrated by a practical example.

This paper is concerned with the problem of load frequency control for multi-area power systems with renewable energy sources penetration which increase the instability of the interconnected power system because of system inertia reduction. In order to tackle this problem, by using the virtual inertia control technique, a new load frequency control model has been proposed to improve frequency stability of the interconnected power system due to the negative impact causing by renewable energy sources. Firstly, load frequency scheme with network induced delays is formulated for multi-area power systems. Secondly, by using the Lyapunov theory and linear matrix inequalities (LMIs) technique, stabilization criteria and H∞controller for the multi-area power systems are derived. Finally, a case study demonstrates the effectiveness and merits of the present method.

This paper is concerned with resilient H∞ triggering control for discrete-time networked control system with parameter uncertainty and aperiodic DoS attacks. First, a switched time delay system model in discrete domain is established to describe the dynamic of discrete triggering control system subjected to DoS attacks. To analyze the H∞ performance of the switched delay system, we combine discrete piecewise Lyapunov-Krasovskii functional method and average dwell time (ADT) based switch system method. Then, the weighted H∞ performance would be preserved if the derived sufficient conditions were satisfied. The main conclusion is a criterion that the allowable margin of the duration and frequency of DoS attacks can be estimated explicitly. Under the criterion, the static output feedback control law can be solved by using LMIs techniques. Finally, we apply our method to design the resilient load frequency control (LFC) scheme of a three-area power system.