A Privacy-Preserving Distributed Control Strategy in Islanded AC Microgrids

As an effective method to improve the reliability, the advanced communication infrastructure also exposes the islanded AC microgrid (MG) to potential privacy threats. Although the existing differential-privacy based secondary controls provide the privacy protection through adding noise, the noise would bring about large harmonic components thereby degrading the power quality. To tackle with this problem, a novel integrated privacy-preserving distributed fixed-time (PDF) secondary control of the islanded AC MG is proposed for the accurate frequency restoration and active power sharing. The state decomposition strategy and the additional virtual proportional (AVP) coefficient are innovatively designed to achieve the privacy preservation, where the active power ratio of each DG is decomposed into several sub-states. The integrated PDF secondary control only requires each DG to transmit the first sub-state of active power ratio through communication network, which would not increase the communication burden. The designed privacy-preserving mechanism can protect the initial value and real-time running values simultaneously when the AVP coefficient is not disclosed to the external eavesdropper. The real-time simulations based on the NI-PXI real-time simulator are conducted to validate the effectiveness and advantages of the integrated PDF secondary control.