The Study Of Capacity Optimization Of Energy Storage System In Wind Farm Considering Reliability

Wind power is random and intermittent, so in order to stabilize the volatility of wind power, we usually need to install energy storage system in the wind farm, and the battery energy storage system is most commonly used. In general, battery energy storage system can be divided into storage battery module, power conversion system and filter. The failure rate of energy storage battery module and power conversion system is relatively high. When a fault occurs in battery energy storage unit, it will not only influence the output power of battery energy storage system, but also may lead to the unbalanced state of charge of different battery cells, which may reduce the life of battery. In addition, the outage of power conversion system will also lead to the outage of storage system.To analyze the effect of battery energy storage system’s reliability on the capacity optimization of energy storage system in wind farm. The paper firstly establishes the reliability model of the battery storage module and the power conversion system, and then analyses the problem of capacity optimization of energy storage system. The main contents can be summarized as follows:1) The reliability model of battery energy storage system is established based on the reliability model of traditional series-parallel system. Considering the series-parallel structure of storage battery module, the paper takes series-parallel battery pack as an example to establish the reliability model of storage battery and then simulates the operation status of storage battery module.2)The general structure of power conversion system is introduced and the reliability model of power conversion system is established. Considering the electrolytic capacitor’s impact on reliability of power conversion system is greatest, the paper mainly focuses on the effect of electrolytic capacitor’failure and simulates the operating state of power conversion system.3) The paper introduces the charge and discharge characteristic parameters of battery energy storage system. And the paper discusses respectively the charge and discharge characteristics of energy-type battery and power-type battery.4) The paper optimizes the storage capacity of battery energy storage system after considering the reliability of battery energy storage system. Firstly, the paper simulates the operating state of battery energy storage system according to the reliability model of battery energy storage system. Then it gives some corresponding strategies for the charge imbalance problem caused by the failure of energy storage battery module. Finally, it establishes the objective function of minimizing the total value of abandon wind cost, energy loss cost, inherent investment cost and battery maintenance cost, and then uses particle swarm optimization algorithm to optimize the storage capacity of battery energy storage system after considering the reliability of battery energy storage system.