【作者】 李桂鑫；

【导师】 姜惠兰；

【作者基本信息】 天津大学 ， 电力系统及其自动化， 2007， 硕士

【摘要】 配电网线损作为电力系统的一项重要的技术经济指标,长期以来受到电力企业及相关部门的广泛重视。特别是电力的市场化改革以来,线损率己经直接与电价挂钩,影响着企业的经营效益。因此,准确而简便的线损计算,对于考核企业线损管理工作成效、制定各项有效地降损措施是极其重要的。本文首先对现有的理论线损计算方法进行了深入分析,指出了目前各种线损计算方法的局限性。并针对我国配电网具有元器件数量众多、分布复杂,自动化程度普遍较低,原始数据不易收集等特点,提出了一种基于遗传算法的RBF神经网络用于配电网线损计算的新方法。该方法通过RBF神经网络的空间拟合性和径向基函数的局部响应特性映射配电线路参数与配电网线损之间的非线性复杂关系,并针对传统的RBF网络学习方法中,隐含层与输出层结构参数的确定相互独立,输出层权重训练容易陷入局部最小等缺点,应用遗传算法对整个RBF网络进行优化,将RBF网络不同的中心和其对应的宽度及各个调节权重统一编码,加强了RBF网络隐含层和输出层的合作关系,并利用遗传算法全局搜索的功能特性,使得整个网络模型达到全局最优。此外,对遗传算法本身的遗传机制作出了相应的改进,使遗传操作更加完善。为了验证本文提出的方法的实用性和可行性,分别以某地区68条配电线路和天津滨海供电局67条配电线路的线路特征参数为样本,进行了线损的实例仿真计算。试验仿真结果表明以遗传算法优化的RBF网络,具有网络模型简单、训练速度快、计算精确度高等优点,并具有很强的实用性和推广性。利用神经网络的拟合能力合扩展能力,可以较为准确的记忆可获取的配电线路特征参数与线路线损之间的非线性映射关系,从而进行较为精确的线损计算。最后,本文以Borland C++ Builder 5.0作为软件开发平台,基于面向对象程序设计的思想,开发出一套适应于配电网线损计算的可视化软件。软件具有配电线路图绘制,元件运行数据录入,数据库管理,线损计算,报表输出等功能。人机界面友好,并提供了大量的快捷操作,具有国际标准软件界面风格,易于用户学习掌握。软件设计后期,进行了多次测试和使用,确保了软件的完整性、安全性和可靠性。更多还原

【Abstract】 The line losses of power distribution network, which had caught much attention of power enterprises and many related organizations, plays a very important role in evaluating the economics of a power system. Since the reform of the power industry, line losses has directly affected the power price, which is vital to the benefit of enterprises.Accurate and convenient methods of calculating the line losses is very important not only to the evaluation of line losses management, but also to the formulations of losses decreasing measurement.Firstly existing methods for calculation of the theoretical line losses is investigated in detail in this paper, and the limitation of them is also pointed out. According to the characteristics of power distribution system in our country, this paper presents a RBFNN based on Genetic Algorithm, which is applied in calculating the line losses of power distribution systems. The radial basis fuction (RBF) neural network, due to its nonlinear processing ability, is used to map complex nonlinear relationship between the line losses and the feature factors in power distribution systems. But in the traditional methods, the parameters of the hidden layer and the output layer are trained separately. The Genetic Algorithm (GA), a global optimization algorithm simulating organic evolution, is used to optimize the parameters of the RBF network. The coding method put all the parameters in one chromosome optimize them synchronously. It can strengthen the cooperation between the hidden layer and the output layer, and optimizes the neural work to avoid the network parameters suffering into partial minimum.In order to validate the practicability and feasibility of this method, this paper has two simulations respectively. A distribution network in some aera with 68 lines and the distribution network of Binhai power company with 67 lines are used as examples. The simulation recults show that the RBF neural network based on GA has so many advantages such as simple configuration, high convergence speed, high precision and so on. It can memory the complex nonlinear relationship between the line losses and the feature factors in distribution network accurately. So the method presented in this paper has good practicability and should be popularized in other areas.At last, based on the OOP (Object Oriented Programming) ideology, this paper developed visual software for distribution network losses calculation on C++ Builder platform. The proposed software has many fuctions including that circuit diagram painting, parameter input, data base management, distribution network losses calculation, report output and so on. It has better performances in software visualization and friendly interface. Provided many shortcuts, which are according to the international standard styles, it is easy for users to study and operate. After the designing phrase, the software was tested for many times in order to make sure the integrality, security and dependability.更多还原