含径流式小水电系统最小切负荷量的鲁棒优化方法研究

发布时间：2018-03-11 11:01

本文选题：盒式集合　切入点：随机变量分布信息　出处：《长沙理工大学》2014年硕士论文　论文类型：学位论文

【摘要】：考虑到大多数径流式小水电都具有无库容、调节能力差、出力大小由天然来水量决定的特征,而这些因素容易导致系统机组频繁的调节,使系统的运行方式发生变化。因此,合理计划并网径流式小水电系统的最小切负荷量问题,对正确制定含不确定因素的电网调度方案具有重要的意义。文章介绍了小水电的国内外研究发展状态、径流式小水电的出力特点,分析了其并网后对系统的影响。在综合对比分析处理不确定性因素的多种概率统计学方法的优缺点的基础上,针对不确定因素引入分别采用盒式不确定集、椭球式不确定集与基于随机变量分布信息的处理随机性问题的鲁棒线性优化方法,同时阐述了对模型化简的对偶理论；根据鲁棒线性优化方法无需提前已知不确定量的概率分布函数的优势,以径流式小水电站的出力作为随机变量,考虑以盒式不确定集描述径流式小水电出力的特征、利用随机变量分布信息描述径流式小水电系统出力的不确定性。将上述的不确定量转化为确定量,建立了在系统运行约束条件下的计及径流式小水电的电力系统的最小切负荷模型。为使模型便于求解,应用对偶理论将上述模型转化为一般线性规划模型。通过对径流式小水电系统接入某个46节点系统,应用对随机变量处理方式不同的基于盒式集合与基于随机变量分布信息的鲁棒线性优化方法进行仿真计算、分析比较。前者的仿真结果表明,径流式小水电系统出力的不确定性对系统最小切负荷量的存在明显影响；径流式小水电站出力估计值的扰动范围不同,其接入地点的差异等因素都会导致全网最小切负荷量的变化；在后者的仿真过程中设定了两种不同的方案,方案一结果表明,对不确定参数的处理方式不同会导致全网最小切负荷量的变化,该模型不仅可以得到最安全的切负荷方案,还能得到多个介于高经济性和强可靠性之间的切负荷方案,可以实行电网规划问题中的灵活决策。方案二结果表明,单独改变系统中某一节点的接入径流式小水电站容量的大小,由于不同节点敏感度的不同,可能会导致系统的最小切负荷的变化；但当扰动小时,改变节点接入的容量值,并不会使系统的最小切负荷量变化。因此,鲁棒线性优化理论能客观地权衡不同切负荷方案下系统规划方案的抉择,为输电网规划方案的选择提供了理论基础。
[Abstract]:Considering that most small runoff hydropower have the characteristics of no storage capacity, poor regulating capacity, and the output force is determined by the natural water quantity, these factors can easily lead to frequent regulation of the system units and make the operation mode of the system change. The problem of minimum load shedding of small hydropower system connected to grid by reasonable planning is of great significance for correctly formulating the power network dispatching scheme with uncertain factors. This paper introduces the research and development status of small hydropower at home and abroad. On the basis of comprehensive comparison and analysis of the advantages and disadvantages of various probabilistic statistical methods for dealing with uncertain factors, the characteristics of runoff small hydropower power generation and its influence on the system after being connected to the grid are analyzed. This paper introduces a robust linear optimization method to deal with stochastic problems based on the information of random variable distribution by using box-type uncertainty set ellipsoidal uncertainty set and stochastic variable distribution information respectively. At the same time the dual theory of model simplification is expounded. According to the advantage of robust linear optimization method which does not need to know the probability distribution function of uncertainty in advance, taking the output force of small runoff hydropower station as random variable, the boxed uncertainty set is considered to describe the characteristics of runoff type small hydropower output. The uncertainty of runoff small hydropower system is described by random variable distribution information. In this paper, a minimum load shedding model of power system with small runoff hydropower is established under the condition of system operation constraint. In order to make the model easy to solve, The above model is transformed into a general linear programming model by using duality theory. A 46 node system is connected to a runoff small hydropower system. The robust linear optimization method based on cassette set and random variable distribution information is simulated and compared with that of random variable processing. The simulation results of the former show that, The uncertainty of the output force of the runoff type small hydropower system has obvious influence on the minimum shedding load of the system, and the disturbance range of the estimated output value of the runoff type small hydropower station is different. The difference of access location and other factors will lead to the change of the minimum shedding load of the whole network, and two different schemes are set up in the simulation of the latter. The results of scheme one show that, Different processing methods of uncertain parameters will lead to the change of minimum shedding load in the whole network. The model can not only obtain the safest load shedding scheme, but also obtain several load shedding schemes between high economy and strong reliability. It is possible to implement flexible decision making in power network planning. The result of scheme two shows that the sensitivity of different nodes is different when changing the capacity of small hydropower station with access runoff of one node in the system alone. It may result in a change in the minimum shedding load of the system; however, when the disturbance is small, changing the value of the node access capacity does not change the minimum shedding load of the system. Robust linear optimization theory can objectively weigh the choice of system planning schemes under different load cutting schemes, which provides a theoretical basis for the selection of transmission network planning schemes.
【学位授予单位】：长沙理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TV747;TM715

【参考文献】