【作者】 刘巍；

【导师】 章健；

【作者基本信息】 郑州大学 ， 电力系统及其自动化， 2003， 硕士

【摘要】 本文分别研究了变电站站址优化和配网自动化开关设备优化配置与定位两个问题，具体内容和所作工作如下。 一、电网规划中变电站站址优化方法的研究 现代电网的复杂性、综合性和整体性都越来越高，因此对电网规划的要求也越来越高，合理的规划会有利于电网运行，节省投资，并且保证电网建设向着科学合理的方向发展。随着计算机技术的发展，电网优化规划有了更多的途径和方法。 电网规划包括很多方面，网架优化是其主要内容。而变电站选不同的地址，必将影响电网网架，因此本文在网架优化的基础上对变电站站址优选做了进一步的研究和分析，并通过计算机软件实现，应用于河南省某地区电网规划工作中，取得了较为满意的结果。 网架优化规划本质上是大规模动态非线性混合整数规划问题，实际中其求解规模和时间都受到很大限制，很难计算出最优解，因此重要对模型进行简化。本文通过线性化处理后将网架优化模型描述为一个最小费用最大流问题，虚拟一个源点和一个汇点，从源点到各变电站节点各引一条单向弧，弧容量为变电站允许的负荷值，弧费用为变电站单位负荷的费用。从所有负荷节点到汇点各引一条单向弧，弧容量为节点负荷值，弧费用为零。问题求解利用网络流中的最小费用最大流算法，既保证了必要的精度，又使得问题求解快速、简单。 变电站站址优化是在满足诸如负荷需求、线路容量、变电站容量等约束的情况下，寻优新建变电站的位置坐标，使某目标值(例如，年综合计算费用、线损等)达到最优。由于变电站位置坐标的寻优为一个非线性规划问题，难以得到目标函数关于决策变量导数的解析表达式，因此为简化问题，本文提出了一种在多约束条件下的变电站站址分层优化策略。内层优化结合最小费用最大流法给出了在变电站站址坐标给定时的最优网架算法；外层优化通过调用网架优化算法，运用非线性规划中的步长加速法实现变电站站址坐标的最优化。因此在确定变电站最优站址的同时，也能实现网架最优。 该方法虽然不一定保证得出全局范围内的最优解，但可以得出一定地理范围内的次最优解，且算法容易实现，同以往传统的选址方法相比较，消除了人为因素，确保了站址和网架的优化，是比较实用的方法。文中算例还从任意选取的不郑州大学工学硕士论文同点开始对最优站址进行探测，结果都收敛于同一个点，大大增加了这个点作为最优点的可能性。 二、配网开关设备优化配置与定位方法的研究 配电自动化是技术进步的必然结果。要求供电线路没有停电事故是不可能的，但应用配电自动化达到停电频数少、时间短、供电恢复快则是完全有可能的。保护用开关设备的作用就是为了隔离故障、限制故障范围、保证非故障部分正常供电，从而提高配网的供电可靠性;同时这些开关设备还担负着改变运行方式、实现经济运行、提高运行灵活性的重要作用，其配置方案不同，可靠性提高的程度及投资的经济性也不同，因此，配电网中开关设备的配置是配网规划与改造的重要内容之一。 本文在分析辐射式配电网结构特点的基础上，抽象提出了开关设备的保护区以及上下游保护区的概念，总结了配电网年停电损失的通用计算方法以及收益计算的方法和数学模型。若整个开关设备配置问题是一个复杂的组合优化问题，则收益就相当于其中的目标函数部分，在寻优过程中需反复对其计算比较，因此，它是研究开关设备定位问题的基础。 配电网开关设备的配置包括开关设备类型、数量、位置的确定，而其优化配置与定位就是从开关设备的备选位置集合中选择一最优方案，使停电收益最大，或开关设备的投入使停电损失的减少最大。本文中开关定位按照先主干后分支的原则进行。由于同时确定开关数量、开关类型和开关位置有很大的难度，主干线路按照断路器、重合器、分段器、熔断器的顺序来分别确定开关的类型和位置，即按照枚举法对每一个备选的开关位置，通过调用停电损失收益模块，停电损失最小的那个开关类型和开关位置即为最优的结果。而分支线路开关位置定位由于其本身的特点，也就是每条分支开关的安装对其他分支开关的停电损失收益没有影响，可以对每一条分支分别进行开关定位，这样减少了计算量，提高了计算速度。该方法用可视化语言通过软件实现，最后通过实例进行验证，得到了满意的结果。更多还原

【Abstract】 In this paper, methods of optimal substation positioning and optimal selection and location of switching devices in distribution power system are studied. Main works as following. 1. Method of optimal substation positioning in power network planningAs modern power system is becoming more highly complex and paying more attention on its performance as a whole, more reasonable power planning is required to achieve more secure and economic power network operation, and to ensure power network construction along a scientific and reasonable direction. With the development of computer technique, more methods appear in optimal planning of power network.The optimization of network configuration is the main content of power network planning. And location of substations will influence network structure. So in this paper optimal substation positioning is studied together with the network configuration optimization. A new method is proposed for those purposes and is realized by computer visual programming. Satisfactory results are obtained when applying the method to power network planning of one county in Henan province.In essence, optimal network planning is a cosmic, dynamic, nonlinear, mixed and integral planning. Because large system scale involved in and the consumed time for solutions are limited when applied to practical power system, and the difficulty to obtain the optimal solutions, it is required to simplify the model. In this article, after linearization, the original optimal model of network planning is simplified as a minimum cost and maximum flow model (MCMFM). The MCMFM is summarized as following. First, suppose a source point and a sink point. Second, draw a unilateral line from source point to every substation node. The line’s capacity is set as corresponding substation’s allowable load value and the line cost is set as the substation’s unit load cost. Third, draw a unilateral line from every load node to the sink point. The line’s capacity is the load value of the node and the cost is zero. Last, use the minimum cost and maximum flow method in graph theory to solve the problem. The result got is relatively accurate and the solving process is quite fast and simple.The problem of optimal substation position is finding the best geographical coordinates of substation to be built to optimize the objective function (e.g. annualsynthetical cost or power loss, etc.) with physical constraints, such as load demand, line’s capacity, substation’s capacity etc. As we know, it is difficult to get differential function of a nonlinear objective function, so for simplifying the problem, a layered optimal strategy for multi-constrained substation positioning is proposed. The inside arithmetic is for optimal network planning with given substation sites applying the minimum cost and maximum flow method. Based on the optimal network-planning arithmetic, the outside arithmetic is for the optimal coordinates of substation position by using one of the nonlinear optimization methods-direct optimization. Therefore, it can realize not only optimize substation position but also the network configuration.Though the method is not always to get the best solutions in the whole scope, it can always provide the secondary best solutions within certain range. Compared with the traditional location methods, it removes the people factors and ensures the result unification of optimal substation position and optimal network structure. So, it is simple and practical.2. Method of optimal selection and location of switching devices in distribution power systemDistribution automation is the inevitable result of technical advancement. It is impossible without any fault and blackout in power system, but it is absolutely possible to reduce the number and time of fault and restore the power supply quickly. The switchers can isolate the faulted branch, restrict the faulted scale and ensure the supply of non-interruptions such that the reliability of distribution power system is improved. At the same time, the switchers are更多还原