Evolution of Reactive Power Market: A Systematic Review of Ancillary Service and Grid Support

With the large‐scale integration of distributed energy sources, considering their intermittent and volatile nature, grid voltage regulation has become more challenging than ever before. Issues such as voltage fluctuations and even two‐way over‐limit violations have become increasingly prominent. To achieve the optimized dispatch of reactive power and the stable operation of the grid voltage, a comprehensive review of the reactive power regulation device and related issues in the ancillary service market is conducted. Firstly, the development history and future trend of the reactive power market are systematically summarized, with a comparison of different power market architectures and their impact on reactive power regulation. Subsequently, the relevant mathematical theories of reactive power pricing are analysed, followed by typical optimization models of the reactive power market. Finally, the current deficiencies and challenges of the reactive power market are concluded. It is noted that research on the reactive power market, adapted to the context of high renewable energy integration, remains scarce, and the collaborative dispatch mechanism for distributed reactive power sources requires improvement. Future research directions are provided in the end.