Switch-adaptive secondary control against FDI attacks in AC microgrids

In this paper, a switch-adaptive secondary control(SASC) is devised to counteract the adverse impacts of false data injection(FDI) attacks on AC microgrids(MGs). Firstly, an FDI observer is established to adjust the secondary control compensation coefficients based on whether the detected FDI surpasses a threshold value, thereby reducing the effect of FDI attacks on the AC MG. Then the system is adaptively controlled according to the frequency-voltage error, which is more accurate compared to a single switch control. Adaptive virtual impedance is used to ensure accurate and proportional distribution of reactive power and to achieve effective harmonic suppression, thus reducing the impact of FDI attacks on reactive power distribution. Contrasted with the conventional virtual impedance control, SASC does not need to consider the line impedance. Finally, simulations and FPGA in the loop experiments verify that the proposed SASC method can defend against FDI attacks in an AC MG.