多时间尺度下基于相关系数的光伏电站出力特性分析

Analysis on the output characteristics of photovoltaic power station based on the correlation coefficient over multiple time scales

随着电力系统中光伏渗透率不断增加,其出力的随机性和波动性对电网运行的影响越来越大。为了研究光伏电站的出力特性,文中分析了光伏发电出力随机特性及光伏电站出力的相关性。首先,根据光照强度概率密度函数和光电转换特性,建立光伏出力概率密度函数,得到不同取值条件下Beta分布概率密度曲线;其次,根据光照强度概率密度函数和光电转换特性的相关关系的定义分析了相关系数的分类,并对比分析Person相关系数和协方差;最后,利用样本数据计算得出相关系数,估计整体相关系数。本研究以青海省海西蒙古族藏族自治州两座光伏电站的出力数据为例,分析了两座光伏电站在不同时间区间内的出力相关性,并通过统计分析的方法对相关系数进行显著性检验表明,两座光伏电站出力特性显著相关。

With the increasing of penetration rate of photovoltaic power system,the randomness and volatility of its output have a greater impact on the operation of power grid.In order to examine the output characteristics of photovoltaic power station,this paper analyzes the random characteristics of photovoltaic power output and the correlation of output of photovoltaic power station.Firstly,the probability density function of photovoltaic output is established according to the probability density function of light intensity and photoelectric conversion characteristics.And the probability density curve of the distribution of beta under different values is also obtained.Secondly,the classification of correlation coefficient is analyzed according to the definition of correlation,and the correlation coefficient of Person and covariance are compared and analyzed.Thirdly,the correlation coefficient is calculated by using the sample data to estimate the overall correlation coefficient.Taking the output data of two photovoltaic power stations in Haixi Mongolian and Tibetan Autonomous Prefecture of Qinghai Province as examples,this paper calculates the output correlation of two photovoltaic power stations in different time intervals and tests the significance of the correlation coefficient using the method of statistical analysis.It is found that the output characteristics of the two PV stations are significantly correlated.