摘要
针对并网情况下光伏出力预测精度低和稳定性差问题,提出了一种基于灰色关联分析(GRA)结合BP神经网络(GRA-BPNN)的变权重系数组合预测模型。首先,利用3种单一预测模型对光伏出力分别进行预测,然后,利用GRA-BPNN模型对3个单一模型不同时刻的权重系数进行预测,最后,根据权重系数计算出预测结果。文章利用武汉某并网光伏电站的实测数据对GRA-BPNN变权重组合预测模型预测结果的准确性进行检验。分析结果表明:GRA-BPNN变权重组合预测模型的相对均方根误差和相对平均误差均低于单一模型和等权重组合模型;根据各预测模型的残差直方图可知,GRA-BPNN变权重组合预测模型预测结果中出现较大残差的概率很小,有效地解决了单一模型预测结果不稳定的问题。
In view of forecast accuracy and stability of grid-connected photovoltaic(PV) power, a variable-weight combination forecast model(GRA-BPNN) based on gray relational analysis(GRA)and BP neural network(BPNN) is proposed. Based on the predicting results of three single forecast models, GRA-BPNN model is used to predict the weight coefficient of the three single forecast model,and then the obtained weighting coefficients is applied to calculate the final forecasting value. The measured data from a PV grid-connected power station in Wuhan is used to test the accuracy of the calculation results of GRA-BPNN variable-weight combination forecast model in this paper. The results show that GRA-BPNN variable-weight combination forecast model performs better than any single model and equal weight combination model with smallest values of the average relative error and relative root mean square error. The histogram of residual errors of forecast model are analyzed, finding out that the probability of the larger residual error of GRA-BPNN variable-weight combination forecast model is small. It can effectively solve the unstable problem of the single predicting model.
引文
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