基于多重信息分解与时变权重组合的换流变压器振动状态参量综合预测方法

振动峰值与频谱复杂度变化趋势反映了换流变压器的内部机械状态,对振动状态参量预测可为换流变压器的状态评估提供有效支持,该文提出一种基于多重信息分解与时变权重组合的换流变压器振动状态参量综合预测方法。首先,根据不同模态划分方法,对原始振动状态参量进行经验小波变换与变分模态分解,得到多个具有趋势性与周期性的模态分量;然后,应用3种预测模型对模态分量预测,集成相加获得单分解单预测模型的预测结果;最后,兼顾主客观因素与逐点分配原则,采用模糊层次分析法与熵权法的时变权重组合方法对不同预测结果分配权重,依照权重结果计算综合预测值。算例分析表明:相比直接预测模型与单分解单预测模型,提出的综合预测方法具有更高的精确度与稳定性,为基于振动法对换流变压器状态监测与故障诊断提供了一种新的思路和有效手段。

基于时变权重组合与贝叶斯修正的中长期径流预报

高精度的中长期径流预报信息是水资源规划管理与水利工程经济运行的重要基础支撑。论文在组合预报与误差修正2类径流预报后处理方法串联应用的技术框架下,考虑径流的高度非平稳与非线性等特征,提出了基于时变权重组合和贝叶斯修正的中长期径流预报方法。应用该方法开展了云南龙江水库年、月入库径流预报的实例研究,结果表明时变权重组合平衡了已建立的随机森林与支持向量机模型在建模期与检验期预报性能的差异,经贝叶斯修正后的预报精度接近或优于两阶段各自的最优单一模型。根据年径流预报结果判断水文年型的正确率达到77.2%,月预报径流的确定性系数超过0.90。因此,该方法在提升中长期径流预报精度方面具有积极效果。

Nonlinear combined forecasting model based on fuzzy adaptive variable weight and its application

In order to enhance forecasting precision of problems about nonlinear time series in a complex industry system,a new nonlinear fuzzy adaptive variable weight combined forecasting model was established by using conceptions of the relative error,the change tendency of the forecasted object,gray basic weight and adaptive control coefficient on the basis of the method of fuzzy variable weight.Based on Visual Basic 6.0 platform,a fuzzy adaptive variable weight combined forecasting and management system was developed.The application results reveal that the forecasting precisions from the new nonlinear combined forecasting model are higher than those of other single combined forecasting models and the combined forecasting and management system is very powerful tool for the required decision in complex industry system.