【作者】 孟晓芳；

【导师】 朴在林；

【作者基本信息】 沈阳农业大学 ， 农业电气化与自动化， 2011， 博士

【摘要】 配电网直接给用户供电,与用户密切相关,对配电网进行科学合理的规划,可以降低配电系统的投资和运行费用,有助于电网的经济建设和运行,具有显著的经济和社会效益。农村电力网是配电网的重要部分,农网的建设关系到发展农业经济、提高农业生产、改善农民生活水平等许多问题,也关系到农网的可靠、经济、合理、高质量、低成本地运行。因此,做好农网规划工作非常重要。在系统地分析农网现状的基础上,提出了基于虚拟技术的农网规划新思想,确定了基于虚拟技术的农网规划应用系统的总体规划及实现方法。提出了构建农网规划虚拟系统的系统方法。根据农网的现状及发展趋势,建立了包括电源、电容器、线路、节点、负荷的图元库,完成虚拟系统的主界面、相关数据库的形成以及农网分析计算结果的显示。在虚拟系统的主界面建立虚拟运行系统,方便地进行农网的运行分析,实现对电气图编辑、绘制、数据的保存以及相关显示。并结合虚拟系统,分析了线路、电容器、负荷及PV节点在配电网潮流计算中的模型,给出了基于网络拓扑方法的配电网潮流计算方法。提出了基于虚拟系统的农网无功优化方法。针对农网无功优化问题,考虑了影响农网负荷统计的不确定因素,并且确定了不确定信息的数学模型。建立了无功优化模型,根据农网的运行特点以及历史数据,建立了三阶梯的负荷曲线。按照最大负荷时网络损耗最小确定补偿位置,然后以计算支出费用最少为目标确定无功补偿容量,并且提出了根据潮流分布确定主干线的方法。实现了农网无功优化结果在虚拟运行系统中的显示,可以直观地分析无功规划优化对不同负荷情况时农网节点电压、支路功率分布、支路损耗的影响,而且可以直观地观察无功补偿设备的位置和容量。提出了基于虚拟系统的分布式电源(DG)在农网中的优化配置方法。给出了适合农网应用的分布式电源类型,研究了农网中DG的配置问题。利用网络的节点优先度评价DG对节点电压、功率损耗以及短路电流的影响。在满足一定优先等级的前提下,根据年电能损失最小及年经济效益最高的原则确定配置DG的位置及容量。在安装DG总容量相同的情况下,将单点配置DG、两点配置DG及三点配置DG对节点电压的改善和电能损失减小的程度进行了计算和对比分析,并且将其显示在虚拟运行系统。借助农网DG规划优化结果在虚拟运行系统中的显示,更加直观地看出通过DG规划优化可以提高节点电压、改善支路功率的分布、减小支路的损耗,而且可以直观地观察DG的位置和容量。提出了农网现有网架结构更新的方法。结合虚拟系统,遵循满足电压质量、投资最小、损耗最低的原则,分析网络的薄弱环节,确定网络的更新方案。为了分析现有网架的薄弱环节,提出了适应度的模型,给出了不满足适应度路径的确定方法。在满足有功和无功功率的平衡、电压降落及电流限制的约束条件下,建立了以投资及损耗最小为目标函数的农网网架的更新模型。提出了根据最小、最大负荷增长率分析网络的适应度的方法,通过算例结果及比较分析,表明了方法的有效性。现有网架更新所需要的数据在虚拟系统的主界面输入,而且更新结果直观地显示在虚拟系统。提出了农网网架结构的规划优化方法。提出了供电区域分区的方法,确定了优化布线和可靠性分析的方法。在考虑地理条件、建筑物、节点电压和支路电流等条件的影响下,根据最短路径和最小负荷矩法优化规划配电网的网架,提出了确定主干线、连接负荷点、选择导线截面及线路拉手前后节点和支路的编号方法。提出了自动搜索连接负荷的交叉点(中间节点)以及相邻线路的联结点的方法,实现了相邻线路的拉手,实现了自动布线功能。为了保证正常运行,网架规划时必须根据拉手前后的潮流分布多次修正后确定网络结构参数。通过实例结果及比较分析,表明了方法的有效性。而且,结合虚拟系统,可以直观、方便地录入数据,自动布线,自动显示网架规划的相关结果。针对本文提出的配电网规划优化的各种方法,编制了相应的算法程序,并通过算例进行了测试和分析,结果验证了本文提出方法的有效性。更多还原

【Abstract】 Distribution network correlates closely to the customers, which can provide a stable long-term supply of electric power to the users. It is important to plan distribution systems scientifically, reasonably and accurately, which can make lower investment and operational costs, and can help to economic development and operation of power system, and can yield remarkable social and economic benefits. Rural distribution system is the important part of the distribution network. The development of rural distribution touches on a wide range of problems such as the development of rural economy, the purpose of raising the level of agricultural production, and the improvement of the peasants’ living standards, and also affects the reliable, economic, reasonable, low-budget and high-quality operation of the rural network. So, it is very important to make an overall plan on the rural distribution system.On the basis of systematically analyzing the the present state of the rural distribution, a new idea of rural power system planning is proposed based on virtual system, and the total planning and the methods are also presented on the same base.The systematic approach is put forward to found virtual system of the rural power network planning. According to the present conditions and its trend of the development in rural system, the elements included power source, capacitor, line, node and load are formed, and the main interface and databases related to the virtual system are completed, and also the relational analysising and computing results of are showed. Virtual system can be established on the main interface, which gets easy to analyze the operation of the rural power system, and easy to achieve the edit and drawing of electric map, and easy to save data, and easy to show the relational results. Combined with the virtual system, the models contained line, capacitor, load and PV node in the power flow of distribution system, and the method of power flow is given based on network topology analysis.Based on the virtual system, the systematic method of reactive power optimization is proposed in the rural power grid. In view of rural reactive power optimization, the load uncertainties are accounted in this paper, and the mathematical models of fuzzy information are determined. The model of rural reactive power optimization is formed. In accordance with operational chariacteristics and the historic data of the rural system, three load levels are given. According to the optimum of power losses at the maximum load to determine the reactive compensation positions, and then reactive power compensation capacity is calculated for the least accounting expenditure cost. On the basis of power flow analysis, the method to determine main line is presented in the rural. The results of reactive power optimization can be showed in the virtual system. And the effects to node voltage, branch power flow and branch power loss are analyzed for different load, and also the sitting and capacity of reactive compensation device can be observed intuitively.Based on the virtual system, the systematic method of distributed generation (DG) is proposed in the rural power network. The type of DG adapted to our rural network is given, and the problem to placing DG is advanced in rural distribution systems. The node priority is employed to describe the DG’s effect of node voltage, power network loss and short-circuit current. According to the annual minimum electric power loss and maximum economic benefit after placing DG, the sitting and sizing of DG is determined under certain node priority. Under the same total capacity, effects of electric power loss and node voltage are calculated and compared by single, double and three sites of DG, which can be showed in the virtual system. In virtue of the optimal results showed in the virtual system, the effects illustrated that the node voltage is greatly improved, the power flow is reformed, and the power loss is significantly reduced, and also the sitting and capacity of DG can be observed intuitively.Optimal approach on renewing framework of upgrading rural power network is proposed in the rural power network. On the basis of the virtual system, and in the light of the principle to satisfied voltage quality, minimum investment, and lowest power loss, the weak part of rural distribution is confirmed, and the renewal schemes of network analyzed is determined. In order to analyze the weak part, the model of adaptabilities is proposed, and the method to confirm paths with bad adaptability is found subsequently. On the basis of satisfied active and reactive power balance, voltage quality, and current limit, and lowest power loss, the renewal model is presented according to the object function of minimum investment and lowest power loss. According to the minimum and maximum load increasing rate respectively, the method is put forward to analyze the adaptabilities of the rural network. The method proposed is applied to a real grid example, and methods are valide by results analysis and comparison.The necessary data can be inputed in the main interface of the virtual system, and the renewal results can be showed in the virtual system.Optimal planning method for distribution network is proposed in the rural power network. The method to partition load area is presented, and the ways to routing optimal problem and analyzing reliability are determined. Under taking account of constraint conditions such as physical conditions, buildings, node voltage, branch current, and so on, and on the basis of the shortest path and minimum load moment algorithm, thn distribution network is optimized and planed, and the approaches are given to determine main line, to connect load node, to select section of the lines and to ordering technology of nodes and branches before and after the lines connected. The methods are given to automatically search the cross point (intermediate nodes) and adjacent join points between two lines, and two adjacent lines can be connected hand in hand. Finally the function of automatic routing is achieved between adjacent lines. In order to ensure nomal operation, the configuration parameters must be modified many times according to the power flow before and after the lines connected. The methods proposed are applied to a real grid example, and methods are valide by results analysis and comparison. Moreover, on the basis of the main interface of the virtual system, the data can be inputed easily, and the autimatic routing and planning results can be showed in the virtual system. In view of the proposed approaches in this paper, corresponding algorithms and programs are made, and those methods are tested on various example grids.The results shows the feasibility of the proposed methods.更多还原