An Adaptive Virtual Impedance Control for Voltage and Frequency Regulation of Islanded Distribution Networks Based on Multi-Agent Consensus

In the islanded operation of distribution networks, due to the mismatch of line impedance at the inverter output, conventional droop control leads to inaccurate power sharing according to capacity, resulting in voltage and frequency fluctuations under minor external disturbances. To address this issue, this paper introduces an enhanced scheme for power sharing and voltage-frequency control. First, to solve the power distribution problem, we propose an adaptive virtual impedance control based on multi-agent consensus, which allows for precise active and reactive power allocation without requiring feeder impedance knowledge. Moreover, a novel consensus-based voltage and frequency control is proposed to correct the voltage deviation inherent in droop control and virtual impedance methods. This strategy maintains voltage and frequency stability even during communication disruptions and enhances system robustness. Additionally, a small-signal model is established for system stability analysis, and the control parameters are optimized. Simulation results validate the effectiveness of the proposed control scheme.