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.

Due to the high R/X ratio and mismatched feeder impedance of low-voltage microgrids, conventional droop method is no longer able to decouple the active and reactive power of distributed generators and the powersharing accuracy is degraded. In this article, a virtual complex impedance based P - V̇ droop method is proposed to decouple the powers and improve the power-sharing accuracy among DGs. With the virtual impedance method, the equivalent impedance between virtual power source and point of common coupling is shaped to be purely resistive. Then, a P - V̇ strategy is adopted to alleviate the effect of mismatched line impedance, where the virtual powers rather than the ordinary P/Q are used in the droop equation. In case the output voltage violates the operation code, a restoration mechanism is proposed to reset V̇ to zero. Compared with existing virtual impedance and Q - V̇ droop methods, the proposed method combines the advantages of both. Besides, a modified P - V̇ strategy is also presented to accelerate the restoration process and improve the active power-sharing accuracy at the same time. Simulation results validate the effectiveness of the proposed method.

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.