平滑可再生能源发电系统输出波动的储能系统容量优化方法

光伏、风力发电等可再生能源(renewable energysources,RESs)具有随机性、间歇性等特点。为了抑制RESs输出波动对电网的不利影响,提出了用于平滑RESs发电系统功率输出的储能系统(energy storage system,ESS)容量优化确定方法。利用离散傅里叶变换(discrete Fouriertransform,DFT)对RESs输出功率进行频谱分析,基于频谱分析结果,考虑ESS充放电效率、荷电状态(state of charge,SOC)及RESs发电系统目标功率输出波动率的约束,确定所需ESS最小容量。采用美国华盛顿州实际观测风速数据及日本东北电力公司风电场接入电网20min有功功率波动规范(最大波动率为10%),在一风力发电系统中对该方法进行了验证。算例结果表明采用该方法能够以较小的容量将风机输出最大波动率由61.7%降到9.9%。

Sizing of Energy Storage Systems for Output Smoothing of Renewable Energy Systems

Renewable energy sources(RESs),such as photovoltaic(PV) and wind power generation,have the characteristics of random fluctuation and intermittence.A capacity determination method of energy storage system(ESS) was presented to inhibit the adverse effects of RESs fluctuations on the power grid.The spectrum analysis results of RESs output were obtained through discrete Fourier transform(DFT).The minimum power and energy capacity of ESS can be determined based on the spectrum analysis results.The determined capacity of ESS can satisfy the constraints of charge-discharge efficiency,state of charge(SOC) of ESS and the upper fluctuation rate limit of RESs target output.The proposed method was verified on a wind power generation system based on historical wind speed data of Washington,USA and grid-connected wind farm 20 minutes active power fluctuation standard(upper power fluctuation rate limit is 10%) of Tohoku Electric Power.The results show the maximum 20 minutes active power fluctuation rate of wind power output can be reduced from 61.7% to 9.9% by a relatively small capacity of ESS determined by the presented method.