基于SOC调整的光伏电站储能系统调控策略

光伏（PV）发电输出功率具有波动幅度大和随机性强的特点，大规模并网光伏电站需要电池储能系统（BESS）对输出功率波动进行平滑抑制，以降低对电网的冲击。提出了一种衡量不同BESS控制策略抑制PV功率波动能力的评价指标，针对现有基本功率平滑控制策略的不足，提出基于电池荷电状态(SOC)调整输出的储能功率控制策略。通过调节BESS输出功率，对PV输出功率中较高频段波动成分进行补偿，并且在储能电池荷电状态（SOC）偏高/低时对输出功率加以自适应调整，在不削弱补偿效果的前提下，将SOC维持在正常范围内。仿真结果表明所提方法在光伏输出波动剧烈时仍有较好的平滑效果，并且对电池容量的需求较小。

Control strategy of battery energy storage system for large-scale PV system based on SOC adjustment

Output of PV generation system features large fluctuation and strong stochastic effect. Battery energy storage system (BESS) is integrated with large-scale PV system to mitigate the power shock to the grid by smoothing out the output power fluctuation. This paper first presents a method to evaluate the capability of different energy storage control strategies to smooth out PV power fluctuations. Then an energy storage control strategy based on state of charge (SOC) adjustment is brought out. In this approach, fluctuation components of PV output power in relatively high frequency domain is compensated by tuning the BESS output power. When the SOC of battery is too high or too low, the BESS output power is adjusted. Thus, the SOC of battery stays in safe zone while the effect of compensation is not deteriorated. Simulation has proved that the method works well even when the volatility of PV output is rather strong, and it does not need a large battery capacity.