Energy Storage Control and Capacity Optimization for Regenerative Braking Power Fluctuation Mitigation Under Port Renewable Energy Integration

ABSTRACT To solve the problems of power fluctuations, voltage violations, transformer overloading and restrictions on renewable energy consumption in ports, which are caused by fluctuation of renewables and regenerative braking power, an energy storage system (ESS) control strategy and a nested bi‐layer configuration method based on lithium titanate oxide (LTO) batteries are proposed to reduce power fluctuations of the ports main grid, enhancing the integration and utilization of renewable energy. The inner layer is the strategy of ESS to suppress power fluctuations in ports. First, with the goal of maximising the utilisation of regenerative energy of quay cranes, a multiple quay cranes collaborative optimisation operation model is established to reduce the total power fluctuation of ports. Then, an ESS coordinated strategy based on Pontryagin's minimum principle is proposed to reduce the fluctuating power of energy‐type ESS. The outer layer is the capacity configuration model of LTO. Based on the power fluctuation of energy‐type ESS, a capacity optimisation model is established with the goal of minimising the annual configuration cost of LTO during the project operation period. The inner and outer layers realise the iterative optimisation of energy storage operation strategy and capacity configuration through operation parameters and capacity parameters interaction. The case study results show that the average power fluctuation of each quay crane is reduced by 26.2% under the cooperative operation (three quay cranes). At the same time, the average power fluctuation of energy‐type ESS is reduced by 26.3% compared with the traditional adaptive first‐order filtering strategy. The average annual cost of LTO is decreased by 17.5% compared to the commonly used lithium iron phosphate battery.