Distributed Secondary Resilient Controller Design for Islanded AC Microgrids Under Stealthy Frequency Sensor Attack

In this paper, the optimal power allocation and frequency restoration problem for islanded alternating-current (AC) microgrids (MGs) is addressed under false data injection (FDI) frequency sensor attacks. Firstly, a distributed proportional and integral secondary controller is developed without considering the FDI attack. In addition to the advantages of the traditional distributed structure, this controller also has more advantages, such as simple tuning and robustness to external disturbances. Also, the theoretical analysis proves that the developed controller can drive the system frequency to the reference value, while the optimal power distribution is realized. Then, a distributed intermediate-estimate-based resilient secondary control strategy is further designed to enhance the resilience of cyber-physical AC MG to FDI attacks on frequency sensors. Compared to most of existing resilient control strategies, our proposed controller can not only maintain the frequency stability, but also ensure the accuracy of optimal power sharing among distributed generators (DGs). Finally, an islanded AC MG test system is built on a real-time testing platform to illustrate and verify the effectiveness of the developed methods.