Cooperative AC/DC Voltage Margin Control for Mitigating Voltage Violation of Rural Distribution Networks With Interconnected DC Link

Abstract

With the integration of high proportion of distributed generation (DG), voltage violation may occur at the point of common coupling (PCC) of feeders in rural lower voltage distribution networks (LVDN). The DC link, with its advantages of large capacity and low line losses, can connect two or more feeders, facilitating broad area power and voltage regulation. At present, the voltage violation solutions based on DC link can be divided into communication-dependent and communication-less scheme. Given the randomness, rapidity, and real-time nature of voltage violation, communication-dependent solutions typically require fast, real-time communication, leading to high costs and significant resource consumption. Existing communication-less solutions, such as the voltage consensus method, while solving voltage violation, incur substantial power losses due to the need for real-time power interactions. This paper proposes a cooperative AC / DC voltage margin control scheme, which takes the DC voltage information as the medium, and can mitigate the voltage violation of rural LVDN under different operation conditions by coordinating the voltage source converters (VSCs) at the end of the feeders and energy storage system (ESS) without communication. In addition, by reasonably setting different AC and DC voltage thresholds, it can avoid unnecessary power interaction between different feeders and reduce the power loss. Finally, the feasibility and effectiveness of the proposed control strategy are verified by simulation.