Adaptive state-of-charge limit based optimal configuration method of battery energy storage system for offshore isolated power grids considering wind uncertainty and frequency stability

Configuring BESS for OIPGs can reduce operational costs and improve the penetration level of wind power. However, OIPG with a high penetration level of wind power is more prone to frequency stability issues. Moreover, the uncertainty of wind power makes configuring the BESS a challenging task. Therefore, an adaptive SoC limit-based optimal configuration method of BESS for OIPGs considering wind uncertainty and frequency stability is proposed to address these challenges. First, the minimum PCS power of BESS is obtained with the frequency stability of OIPG taken into consideration. Second, a wind power processing framework based on GMM-K-means is proposed to eliminate the negative impact of wind power uncertainty. Third, an adaptive SoC limit-based two-layer optimal configuration model of BESS is established to achieve the minimum operational cost of OIPG. Fourth, the PCS power, the capacity, the lower SoC limit, and the operating plan of BESS are obtained through the proposed method. Finally, a case study is conducted to validate the effectiveness and correctness of the proposed method. The case study demonstrates that 1) the minimum PCS power constraint ensures that the configured BESS has enough power and energy to provide frequency support to improve the frequency stability of OIPG, 2) the proposed wind power processing framework has better clustering and cleaning effects compared with traditional methods, and 3) compared with traditional optimal configuration methods, the proposed adaptive SoC limit-based optimal configuration method can further reduce the daily costs of OIPG by approximately 1 %. • Two-layer optimal configuration model of BESS: Considering both economic operation and frequency stability of OIPG, a two-layer optimal configuration model to determine the optimal PCS power, capacity, lower SoC limit, and operating plan of BESS is proposed. • Wind power data processing framework: A comprehensive wind power processing framework based on GMM-K-means is proposed to address the wind uncertainty and enhance the reliability of the configured BESS. • Adaptive SoC limit strategy: the lower SoC limit of the BESS in the proposed optimal configuration model is treated as a decision variable, which can further reduce the operational cost compared with fixed SoC-based traditional optimal configuration methods.