An optimized cascaded controller for frequency regulation of energy storage integrated microgrid considering communication delays

The unpredictable nature of renewable energy sources (RESs) and varying loading conditions, coupled with their inherent intermittency in output power, pose significant challenges to microgrid stability. These challenges manifest in hefty frequency fluctuations, which can compromise microgrid reliability. Battery Energy Storage Systems (BESS) emerge as a promising solution to mitigate uncertainties associated with RESs by dynamically adjusting their charging and discharging patterns in response to frequency fluctuations. However, individual BESS units often prove insufficient in regulating frequency within a microgrid. Consequently, BESS aggregation, either through physical grouping or virtual aggregation such as cloud energy storage (CES), becomes imperative. The operation and control of BESS aggregators rely on effective communication of monitoring and control signals. However, these communication signals experience communication delays, which are often overlooked in existing literature. To address this gap, this paper proposes a delay tolerant cascaded fractional order proportional resonant (PR) controller (CFO-(PR)2) for microgrid with ES aggregators. The proposed controller is tuned through a novel hybrid Beluga Whale Technique and Local Unimodal Sampling (hBWT-LUS) method, demonstrating superior performance compared to existing techniques. The IEC 61850 communication design for isolated microgrid (IMG) with ES aggregator is developed and realistic communication delays for frequency regulation are calculated. Performance comparison of the proposed controller with existing controllers in the presence of communication delays is presented. The results show the immunity in the performance of the proposed controller after including communication delays.