【作者】 戴博；

【导师】 张建华；

【作者基本信息】 华北电力大学（北京） ， 电力系统及其自动化， 2009， 博士

【摘要】 电压稳定边界由局部分岔点所构成的边界组成,这些局部分岔点的类型包括以下三种:鞍点分岔(Saddle-Node Bifurcation),Hopf分岔和奇异诱导分岔(Singularity-InducedBifurcation)。寻找最近的局部分岔点及相应控制参数变化轨迹对正确确定系统电压稳定边界具有十分重要的意义,为电网的安全经济运行,合理制定发电计划提供可靠的依据。本文应用非线性动力学的分岔理论,充分考虑电力系统发电机和励磁的动态特性,重点研究了动态电力系统电压稳定分析中的动态局部分岔现象,更明确地说,深入研究了由于负荷增长导致系统发生鞍点及Hopf分岔的原因及其导致系统发生这些分岔的最危险的负荷增长模式;提出了求取最近鞍点及Hopf分岔点的通用算法及其计算电压稳定边界(VSM)灵敏度指标,并针对大规模电力系统的特性提出了寻找对控制变量最灵敏的关键特征值计算方法,并将之应用于大规模电力系统的稳定分析中。本文工作主要包括以下几个方面:1)考虑不同的负荷增长方式对电压稳定裕度的影响,本论文应用分岔理论对动态电力系统电压稳定进行分析。将负荷增长做为控制参数,寻找系统鞍点分岔点。并根据分岔超平面的连续且凸的特性,在发生分岔的超平面求取分岔点的法向量,通过所求法向量计算求取更新的负荷增长方式,采用迭代的方法修正负荷增长方式,进而求取发生最近鞍点分岔点的最危险的负荷增长方式。2)电压失稳包括单调型和振荡型失稳两种类型。所以电压稳定边界亦由鞍点和Hopf两类分岔类型所决定。因此在本论文中,在多维参数空间下,将稳定边界推广到鞍点和Hopf分岔点构成的混合稳定边界,探索性寻求Hopf分岔超平面的法向量,采用迭代算法求取系统发生最近振荡型电压失稳的负荷增长方式。本论文并且讨论了由于负荷模型以及发电机无功出力极限对稳定边界的影响。3)本文以系统从初始运行点到最近分岔点的负荷有功的几何距离做为电压稳定裕度。考虑到电力市场下的输电堵塞,以系统满足必需的电压稳定裕度作为电压稳定约束,结合系统经济调度其他约束条件,采用二次规划优化算法对系统实施预防和校验控制,对发电机的有功出力再调整和必要的负荷削减,以提高系统运行的稳定性和经济性。4)局部分岔分析离不开求解矩阵特征值。针对大规模电力系统求取特征值的困难性,本论文采用改进的隐式重启Arnoldi算法实现了距离虚轴最近的特征值的求取。考虑到大规模电力系统特征值分布的成簇性,本文将求取对控制参数最敏感特征值的算法加入到改进的隐式重启Arnoldi算法中,实现了大规模电力系统的对控制变量最敏感的关键特征值的计算。更多还原

【Abstract】 Power system stability boundary is constrained by three kinds of local bifurcations: Saddle-Node bifurcation,Hopf bifurcation and Singularity-Induced bifurcation.The determination of local bifurcation points and the trajectories of corresponding control parameters are very important for the power system stability evaluation,safe and economic operation as well as reliable generation scheduling.This thesis focuses on the local bifurcation occurance phenomenon,based on bifurcation theory of nonlinear dynamic system, with the dynamic characteristics of generators and excitation systems consideration.More explicitly speaking,this thesis mainly studied the reason which causes The work and attribute of the thesis is shown below:1) Dynamic voltage stability is deeply studied based on the local bifurcation theory with load increase pattern consideration.Load increase pattern is regarded as control parameters which lead the dynamic system to the stability boundary.Saddle-node bifurcation points are found with a given load increase pattern and the closest Saddle-node bifurcation point is found through the proposed iterative method,followed with the most dangerous load increase pattern obtained.2) There are two types of voltage instabilities:monotonic voltage instability and oscillatory one.The oscillatory voltage instability corresponds to the Hopf bifurcation.In this thesis,the voltage stability boundary is the combined boundary which correspond to Saddle-node bifurcations and Hopf bifurcations.The closest Hopf bifurcation point is found through the proposed iterative method under the assumption that the Hopf hypersurface is continuous and convex.The most dangerous load increase pattern is alos obtained.3) Voltage stability margin(VSM) is the smallest geographic distance of the current load level to the load level where bifurcation occurs.Nonlinear planning optimization algorithm is adopted in this thesis to reschedule the active power output of generators and shed load to satisfy the VSM requirement of power system operations.4) Eigenvalue calculation is the most important part in local bifurcation studies.To solve the difficulties in large scale power system eigenvalue calculation and obstacles eigenvalue analysis in large scale state matrix,modified implicit restared Arnoldi method is adopted with the sparse matrix technology usage.Math library IMSL and the open sourse math library Arpack are combined in this thesis to realized the above mentioned technologies.The most sensitive eigenvalue to the control parameters is selected by employing SPA method and the critical eigenvalue is determined based on the calculated eigenvalue.更多还原