基于潮流算法的静态电压稳定性分析方法研究

发布时间：2018-04-23 04:01

本文选题：电压稳定性 + PV曲线　；参考：《太原理工大学》2014年硕士论文

【摘要】：随着用户日益增长的电力需求和地域间电网互联程度的提高,局部电力系统已接近电压极限运行状态,电压稳定问题日益突出。由电压稳定性所引起的大面积停电事故不仅造成了巨大的经济损失,还给人们的正常生活带来极大不便。因此,电压稳定性分析问题越来越受到国内外专家的广泛关注。本文考虑负荷变动对系统静态电压稳定性的影响,研究基于潮流算法的静态电压稳定性分析方法。主要包括以下内容。 (1)研究静态电压稳定性分析方法和概率潮流算法。即从电压稳定性的概念出发,分析电压崩溃的起因等。详述近些年来静态电压稳定性分析方法的研究现状。介绍概率潮流算法的概念及其研究现状。 (2)利用改进连续潮流法(the Improved Continuation Power Flow, ICPF)分析静态电压稳定性。介绍了求解常规潮流方程的常用算法：牛顿-拉夫逊法,并将其作为本文静态电压稳定性分析的基础潮流算法；在此基础上详细介绍了用于静态电压稳定分析的连续潮流算法。并详细叙述对原有连续潮流算法所做的改进,改进后的连续潮流算法可分析系统在正常或是故障运行情况时单节点、多节点、随机节点增加等方式下的静态电压稳定性。 (3)利用改进二分搜索法(the Improved Bisection Searching Technique, IBST)分析静态电压稳定性。简要叙述二分搜索法的基本原理及其在数学和计算机中的应用,并结合二项搜索法在求解电力系统处于电压崩溃时的负荷增长比例、绘制PV曲线的上半分支、获取电压崩溃点信息等方面的应用,提出用改进的二分搜索法分析指定负荷增长模式下的静态电压稳定性。 (4)利用基于半不变量的概率潮流算法分析静态电压稳定性。计及发电机和负荷的不确定性,建立交流概率潮流的节点电压方程,得出节点电压的线性化交流概率模型；并结合半不变量和Gram-Charlier级数展开计算各节点电压概率密度函数(Probability Density Function, PDF)。据此可直接判断出各节点电压幅值是否处于在允许波动的范围内,定性分析系统网架结构应对负荷波动的能力。 (5)算例分析。将上述三种方法分别应用于IEEE-30节点和IEEE-14节点系统,并基于MATLAB软件平台编程计算。首先,将改进连续潮流算法和改进二分搜索法应用于IEEE-30节点系统,得到正常运行和线路故障状态时,多种负荷增长方式下系统达电压崩溃点的各节点电压幅值和电压变化率等指标,通过该指标分析各种情况下的静态电压稳定性。并将这两种算法计算结果加以对比。结果表明,改进二分搜索法在计算时间和算法收敛性方面优于改进的连续潮流算法。其次,将基于半不变量的的概率潮流算法应用于IEEE-14节点系统,描绘系统正常运行和线路断线故障状态下的节点电压概率密度函数图像,并利用该图像分析系统静态电压稳定性。最后,将基于半不变量的概率潮流算法与蒙特卡洛法的计算结果进行对比。结果表明,基于半不变量的概率潮流算法在计算速度、存储空间的方面都优于蒙特卡洛法。
[Abstract]:With the increasing power demand of users and the increase of inter - regional power grid interconnection , the local power system has approached the operational state of voltage limit , and the problem of voltage stability is increasingly prominent . The problem of large - area power failure caused by voltage stability not only causes huge economic loss , but also brings great inconvenience to the normal life of people . Therefore , the analysis of voltage stability is more and more attracted by experts at home and abroad . Considering the influence of load fluctuation on the static voltage stability of the system , the static voltage stability analysis method based on power flow algorithm is studied .

( 1 ) The static voltage stability analysis method and the probabilistic power flow algorithm are studied , which is based on the concept of voltage stability , analyzes the causes of voltage collapse , and details the current research status of static voltage stability analysis methods in recent years .

( 2 ) The static voltage stability is analyzed by using the improved continuous power flow ( ICPF ) method . A common algorithm for solving the conventional power flow equation is introduced : Newton - Raphson method , which is used as the basic power flow algorithm for static voltage stability analysis in this paper ;
On this basis , the continuous power flow algorithm for static voltage stability analysis is introduced in detail . The improvement of the original continuous power flow algorithm is described in detail . The improved continuous power flow algorithm can analyze the static voltage stability of the system under normal or fault conditions , such as single node , multi - node and random node .

( 3 ) The stability of static voltage is analyzed by improved bisection search technique ( IBST ) . The basic principle of binary search method and its application in mathematics and computer are briefly described , and the application of two - item search method in solving the load growth ratio of power system in voltage collapse is introduced , the upper half branch of PV curve is drawn , voltage collapse point information is obtained , and the static voltage stability in the specified load growth mode is analyzed by improved dichotomy search method .

( 4 ) analyzing the static voltage stability by using the probabilistic power flow algorithm based on the semi - invariant , and establishing a node voltage equation of the alternating current probability flow according to the uncertainty of the generator and the load , and obtaining a linearized AC probability model of the node voltage ;
Probability Density Function ( PDF ) is calculated by combining semi - invariant and Gram - Charlier series . In this way , it can be directly judged whether the voltage amplitude of each node is within the range of allowable fluctuation , and the network frame structure of the qualitative analysis system should be able to cope with the load fluctuation .

( 5 ) The three methods are applied to IEEE - 30 node and IEEE - 14 node system respectively , and are programmed and calculated on the basis of MATLAB software platform . First , the improved continuous power flow algorithm and improved dichotomy search method are applied to IEEE - 30 node system . The results show that the improved dichotomy search method is superior to the improved continuous power flow algorithm in terms of computing time and algorithm convergence . The results show that the improved dichotomy search method is superior to Monte Carlo method in computing speed and storage space .

【学位授予单位】：太原理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM712

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