用于能量调度的风–储混合系统运行策略及容量优化

Capacity Optimization and Operational Strategy of the Wind-Energy Storage Hybrid Systems for Energy Dispatching

随着风力发电渗透率的日益提高,风电波动给电网带来了大量的负面影响。采用超级电容–蓄电池混合储能系统平衡风功率和风电场计划出力之间的偏差。首先,采用经验模态分解技术(empirical mode decomposition,EMD)将电网中的计划出力与原始风功率之间的不平衡功率(unbalanced power,UP)分解成若干固有模态函数(intrinsic mode functions,IMFs)。其次,以各固有模态函数之间能量混叠最少为原则确定"划分频率",将不平衡功率分解成为高频分量和低频分量,并分别采用超级电容和蓄电池对其进行平抑。最后,以风电场实际出力数据为基础,设计了同时考虑投资成本与调度效果的混合储能系统(hybrid storage system,HSS),计算结果验证了所提方法的有效性。

Wind power output fluctuation brings a lot of negative influences on utility grid as a result of increasing penetration level of wind power. A supercapacitor-battery hybrid storage system is proposed to balance the wind power and planned export power of the wind farm. Firstly, using empirical mode decomposition（EMD）, the difference between planned export power and the original wind power（unbalanced power, UP） is analyzed to obtain the intrinsic mode functions（IMFs）. Secondly, a mathematic method is then developed to confirm a so-called gap frequency to decompose the unbalanced power into high and low frequency components based on the concept of minimum overlap energy. Unbalanced power smoothing is then achieved by dispatching the powers of supercapatiors and batteries to compensate the high- and low-frequency IMFs according to the characteristics of supercapacitor and batteries respectively. Finally, based on a set of data acquired from an existing wind farm, a hybrid storage system（HSS） is designed aiming at minimizing the capital cost and also can make wind power approach the planned export power of the wind farm in a great extent, numerical analysis verifies the efficiency of the developed method.