一种基于改进总体经验模态分解与反向传播神经网络的短期负荷预测方法（英文）

目的:短期电力负荷预测是电力系统安全调度、经济运行的重要依据。研究处理非线性、非稳态电力负荷信号的新方法,建立短期负荷预测的混合模型,提高短期负荷预测的精确度。创新点:1.提出一种改进总体经验模态分解(EEMD)方法,抑制传统EEMD方法中的端点效应问题;2.提出一种基于改进EEMD和反向传播神经网络(BPNN)的短期负荷预测方法。方法:1.使用改进的EEMD方法将非稳态、非线性的电力负荷信号分解为一系列的内禀模态函数和一个趋势余量;2.移除所得的高频内禀模态函数;3.使用BPNN分别预测各内禀模态函数及趋势余量;4.使用BPNN组合各内禀模态函数及趋势余量预测结果,即为最终负荷预测结果。结论:1.所提出的改进EEMD方法能有效抑制传统EEMD方法中的端点效应问题;2.在相同条件下,所提出的基于改进EEMD和BPNN的短期负荷预测方法较BPNN、EMD-BPNN、EEMD-BPNN、SARIMA-BPNN、WTNNEA和WGMIPSO预测方法有更高的精确度。

An immune-tabu hybrid algorithm for thermal unit commitment of electric power systems

This paper presents a new method based on an immune-tabu hybrid algorithm to solve the thermal unit commitment （TUC） problem in power plant optimization. The mathematical model of the TUC problem is established by analyzing the generating units in modem power plants. A novel immune-tabu hybrid algorithm is proposed to solve this complex problem. In the algorithm, the objective function of the TUC problem is considered as an antigen and the solutions are considered as antibodies, which are determined by the affinity computation. The code length of an antibody is shortened by encoding the continuous operating time, and the optimum searching speed is improved. Each feasible individual in the immune algorithm （IA） is used as the initial solution of the tabu search （TS） algorithm after certain generations of IA iteration. As examples, the proposed method has been applied to several thermal unit systems for a period of 24 h. The computation results demonstrate the good global optimum searching performance of the proposed immune-tabu hybrid algorithm. The presented algorithm can also be used to solve other optimization problems in fields such as the chemical industry and the power industry.

基于Hamilton原理的双跨转子系统建模和转子动态特性分析(英文)

研究目的:研究双盘双跨转子/轴承/汽封系统在非线性油膜力和非线性汽封力共同作用下的动力学特性,分析了转子转速、密封力、油膜力和联轴器刚度等因素对转子稳定性的影响。创新要点:采用Hamilton原理和有限元方法建立双盘双跨转子/轴承/汽封系统模型,使得双跨多节点的转子系统数值求解更加容易。研究分析转子转速、非线性密封力、非线性油膜力和联轴器刚度等因素对转子稳定性的影响,为大型转子系统的设计提供理论基础。研究方法:采用Hamilton原理和有限元方法建立双盘双跨转子/轴承/汽封系统模型(图1和2)。应用四阶Runge-Kutta法进行数值求解,并采用轴承处、圆盘处的分岔图、时程图、庞加莱映射图、频率图和相轨迹图等来分析转子系统的动态特性。重要结论:1.通过数值计算分析,转子的转速、非线性汽封力、非线性油膜力和联轴器的刚度对双跨转子的稳定性有重要的影响作用。2.随着转速的上升,双跨转子系统从最初的稳定运动,到三倍周期运动,到准周期运动和多倍周期运动交替出现,运动特性相比单跨转子系统要更为复杂。