同伦—连续方法在大规模电网分析中的算法及应用

发布时间：2018-06-06 20:26

本文选题：配电系统 + 同伦-连续方法　；参考：《天津大学》2014年博士论文

【摘要】：近年来，，分布式发电的开发和布署呈现快速增长的趋势，加上新型分布式发电技术的涌现，给传统的配电系统分析、设计和控制带来了深刻的变化。因此，发展综合型分析工具评估大量分布式发电接入对配电系统的影响，进而通过协调控制消除负面的影响具有非常重要的意义。同伦－连续方法是一种鲁棒的数值方法，成功应用于求解物理和工程领域的多种问题，常用于克服牛顿－拉夫逊法等迭代方法的局部收敛性。本文采用三阶段的同伦增强框架，开发了可扩展的同伦－连续算法库，发展了同伦增强的配电牛顿潮流和同伦增强的输电潮流，并分别提出了相应的简单问题构造方法，既发挥牛顿－拉夫逊法在轻度或中度负载情况下二次收敛的优势，也能有效克服初值问题、病态或奇异引起的不收敛，提高了潮流计算整体的收敛性。分布式电源、特别是可再生分布式电源接入后，配电网的非线性行为变得更加复杂。由于分布式电源给配电三相潮流方程引入许多PV节点，除了传统的鞍结点分岔以外，另外一种特殊的分岔－结构诱导分岔也可能在配电系统中出现。本文对配电网中的局部分岔机理进行了研究，并提出了相应的分岔计算方法。连续方法是追踪一个或多个参数变化下解曲线的有效方法。本文提出一种称为CDFLOW（Continuation Distribution Power Flow）的分析工具，它可以快速、可靠的计算参数变化下的解曲线和精确分岔点，帮助运行人员充分挖掘现有配电网络的送电潜力，以便消纳更多分布式发电和给更多负荷供电，从而提高配电网资产利用率。各种分布式电源的集成给配电网的运行带来巨大挑战，特别是可再生能源分布式发电，由于它们一般在气候适宜地区就地接入配电网，容易在局部电网引起配电线路和变压器的过载、电压越限和电压稳定问题。本文提出了考虑电压极限、热极限和电压稳定极限的配电网可用送到能力（AvailableDelivery Capability，ADC）问题的数学模型，并提出了精确计算ADC的数值方法。然而，确定性的可用送电能力评估忽略了配电系统中的不确定因素，例如分布式发电和负荷的随机波动，本文基于分布式发电功率预测误差随不同时间尺度、不同风速/光强变化的特点，提出一种依据误差分布确定可信采样区间的场景生成方法，使得场景的生成更精细、更有效。向前看和日前的概率ADC评估可以给出电压越限ADC、热极限ADC和电压崩溃ADC的置信区间，并识别网络中潜在的薄弱节点和支路，相对单个数值，信息更加完整。
[Abstract]:In recent years, the development and deployment of distributed power generation has shown a rapid growth trend, coupled with the emergence of new distributed generation technology, to the traditional distribution system analysis, design and control brought profound changes. Therefore, it is of great significance to develop a comprehensive analysis tool to evaluate the impact of a large number of distributed generation access on the distribution system, and then to eliminate the negative effects through coordinated control. The homotopy continuous method is a robust numerical method. It has been successfully applied to solve various problems in physics and engineering, and is often used to overcome the local convergence of iterative methods such as Newton-Raphson method. In this paper, an extensible homotopy continuous algorithm library is developed by using a three stage homotopy enhancement framework. The homotopy enhanced distribution Newtonian power flow and homotopy enhanced transmission power flow are developed, and the corresponding simple problem construction methods are presented respectively. Newton-Raphson method can not only give play to the advantage of Newton-Raphson method in the case of mild or moderate load, but also effectively overcome the initial value problem, sick or singular caused by non-convergence, and improve the global convergence of power flow calculation. Especially, the nonlinear behavior of distribution network becomes more complicated after the renewable distributed generation is connected. In addition to the traditional saddle node bifurcation, a special kind of bifurcation, structure-induced bifurcation, may also occur in the distribution system because of the introduction of many PV nodes to the three-phase power flow equation of the distribution system by distributed power generation. In this paper, the mechanism of local bifurcation in distribution network is studied, and the corresponding bifurcation calculation method is put forward. The continuous method is an effective method to trace the solution curve of one or more parameter changes. In this paper, an analytical tool called CDFLOWN continuous Distribution Power flow (CDFLOWN) is proposed. It can quickly and reliably calculate the solution curves and exact bifurcation points under the change of parameters, and help operators to fully exploit the power transmission potential of existing distribution networks. In order to absorb more distributed generation and to supply more loads, thus increasing the utilization rate of distribution network assets. The integration of various distributed power sources poses great challenges to the operation of the distribution network, especially renewable energy distributed generation, Because they are connected to the distribution network in the suitable climate area, it is easy to cause overload of distribution lines and transformers, voltage overruns and voltage stability problems in local power networks. In this paper, a mathematical model for the availability of available delivery capability (ADCC) of distribution network considering voltage limit, thermal limit and voltage stability limit is presented, and a numerical method for accurate calculation of ADC is presented. However, deterministic assessment of available power transmission capacity ignores uncertainties in distribution systems, such as random fluctuations in distributed generation and load. In this paper, the prediction error of distributed generation power varies with different time scales. Based on the characteristics of different wind speed / light intensity, a scene generation method based on the error distribution to determine the trusted sampling interval is proposed, which makes the scene generation more precise and effective. Looking forward and the probabilistic ADC evaluation before the day can give the confidence intervals of voltage overrun ADC thermal limit ADC and voltage collapse ADC and identify the potential weak nodes and branches in the network. The information is more complete than a single value.
【学位授予单位】：天津大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TM744

【参考文献】