Abstract: [Objectives]　The lack of grid support in offshore islands, significant seasonal variations in renewable energy output and load levels, and the absence of long-term energy storage methods result in large-scale wind and solar curtailment and high carbon emissions. Coordinating multiple flexible resources between different island microgrids via tie lines to achieve power sharing and economic operation has become a current challenge. To address this, a distributed coordination optimization strategy based on the locally adaptive alternating direction method of multipliers (LA-ADMM) is proposed.[Methods]　Firstly, the microturbine, battery energy storage, and flexible load within the island microgrid cluster are modeled. Secondly, an economic optimization model is established, considering operation and maintenance costs, environmental costs, power transaction costs, and network costs. Finally, the model is solved using LA-ADMM algorithm.[Results]　While ensuring the power supply-demand balance of the microgrids, when the flexible load, battery energy storage, and microturbine are individually integrated into the scheduling, the maximum reduction in the comprehensive operation costs of the island microgrids are 4.223%, 5.316%, and 6.326%, respectively. Additionally, the time required to solve the optimal operation strategy using the LA-ADMM algorithm is 41.38% faster than that using the ADMM algorithm.[Conclusions]　The proposed method can not only accelerate the solution speed of the distributed optimization strategy, but also achieve the economic operation of the system.

Key words: microgrid, island, microgrid cluster, distributed coordination optimization, locally adaptive alternating direction method of multipliers (LA-ADMM), power sharing, multiple flexible resources