With the rising proportion of renewable energy in power systems, electricity markets are confronting escalating challenges driven by the accumulation of imbalance funds, especially in high renewable penetration sending-end grids with large-scale high voltage direct current (HVDC) transmission. Existing studies have not fully addressed the impact of renewable energy volatility and HVDC plan deviations on imbalance settlement, and lack an optimization framework that balances market fairness and system security constraints. This paper takes the electricity market of a northwestern province in China as the research object, first identifies the main sources of imbalance funds, and then develops a multi-objective settlement optimization model centered on minimizing imbalance funds, which integrates system power balance, nodal voltage limits, generation plan deviation, and HVDC transmission constraints. A responsibility attribution-based imbalance fund allocation mechanism is further proposed to improve market fairness. Empirical analysis based on actual market data shows that the optimized settlement mechanism reduces imbalance funds by an average of 28.9% under typical scenarios, and significantly improves market operational efficiency. This study provides a practical solution for the sustainable development of high renewable penetration electricity markets.
Fang et al. (2026) studied this question.