在风电预测中,传统的经验模态分解法将风速信号分解为若干具有不同特征尺度的数据分量时,其所得分量可能存在模态混叠现象,影响风速预测的精度.为此,提出一种基于掩模经验模态分解法和遗传神经网络的风速预测组合模型.首先,通过掩膜信号法(masking signal,MS)对经验模态分解法进行改进,将风速信号分解为频率相对固定、更为平稳的分量.之后,利用遗传神经网络算法分别对这些分量进行预测,将各分量预测结果叠加后得到最终风速预测值.通过C++语言编程进行算法实现,采用实际风场数据进行仿真,其结果表明,所提方法计算时间较短,预测精度较高,特别适用于在线超短期(10 min)和短期(1 h)的风速预测,具有实际的工程应用价值.
As an indispensable precondilion, reasonable design of circulating water pump (CWP) intake pit plays a vital role ensuring the secure and ecomomic operation of CWP and eirculating water system in nuclear" power" plants (NPP). According to Froude similarily criteria. a test model with the scale ratio of 1:30 is designed and used in flow distribution test, free surface vortex test and submerged vortex lest for a certain coastal NPP phase one project. The flow distribution countermeasures and anti-vortex device are determined based on the, model test resuhs, which is of great practical significance for the project construetion such that solid foundations can be laid for the subsequent CWP intake pit design.