小阻抗支路对潮流计算收敛性的影响和处理

常规潮流算法在应用于含小阻抗支路电网的计算中存在有收敛性问题.通过对含小阻抗支路电网算例的试算分析发现,在当前普通个人计算机性能条件下,使用双精度类型变量,利用高斯赛德尔法迭代两次选取初值后再使用牛顿拉夫逊法,不需要附加处理就可以解决含小阻抗支路电网潮流计算收敛性问题.将该方法应用于三个地区级电网能量管理系统的调度员潮流计算模块,表明所提方法对于解决实际问题的可行性和有效性.     

小阻抗支路对牛顿法潮流的影响及其处理方法

在分析小阻抗支路对牛顿法潮流影响的基础上,结合电力系统的网络的特点,提出了一种选取牛顿法潮流电压初值的新方法－－小阻抗支路零功率法。分析与计算结果表明,中所提方法能够较好地解决牛顿法在计算含有小阻抗支路系统的潮流收敛性问题。     

网络分析中零阻抗支路的处理

在潮流、状态估计等网络分析程序中为区分负荷类型和确定某些开关中的潮流需设置零阻抗支路。通常的处理方式是用小阻抗支路代替零阻抗支路,经验表明在大多数情况下是允许的,但在某些情况下会加大计算误差和使收敛性变坏。因此,高质量的网络分析程序对零阻抗支路需采用专门的处理算法:一是合并其两端的母线,得到状态量后再设法分开母线;二是针对零阻抗支路列出方程和状态量,加入到网络方程中一起求解。这样处理零阻抗支路,既不降低计算精度也不影响收敛性。在华北、华中和华东的160～340母线系统的潮流和状态估计的模拟计算中取得了良好的效果。     

PQ分解法潮流求解含有小阻抗支路系统的收敛性分析

从潮流计算的基本方程出发,通过对迭代过程中小阻抗支路两端电压的幅值和相角的变化规律的分析,得出了PQ分解法潮流计算含有小阻抗支路的系统能够很好收敛的原因.从理论上为求解这类问题找到了快速、可靠的算法.     

PQ分解法潮流求解含有小阻抗支路系统的收敛性分析

从潮流计算的基本方程出发 ,通过对迭代过程中小阻抗支路两端电压的幅值和相角的变化规律的分析 ,得出了PQ分解法潮流计算含有小阻抗支路的系统能够很好收敛的原因。从理论上为求解这类问题找到了快速、可靠的算法     

配电网潮流计算的回路阻抗法

由Ｓ．Ｋ．Ｇｏｗｓａｍｉ等人提出的回路阻抗法是配电网潮流计算的一种有效方法,它处理网处能力较强,收敛性较好,但其节占和支路编号处理复杂。本文研究提出了一种简单可行的节点和支路编号方法,并对其求解过程进行了有效改进,显著提高了其计算速度。     

利用特殊的数据结构和支路电流迭代法计算配电网潮流

本文针对配电网存在的辐射状拓扑结构,Ｒ／Ｘ值较高,ＰＶ节点少等特点引起的牛顿一拉失逊法及ＰＱ分解法不易收敛的问题,提出了利用以支路电流迭代为核心的新算法,并建立了一套适合于配电网的数据结构,提高了计算效率。     

随州EMS系统中对零阻抗支路的改进处理方法

为有效利用母联开关上配备的有功和无功量测,电力系统中的母联开关被抽象成连接在两个母线节点间的零阻抗支路;另外,在有些三绕组变压器的等值模型中,由于中压侧阻抗很小带来计算过程中的数值不稳定性,也可使用零阻抗支路的改进处理方法。深入分析了与零支路相关的各类量测,采用了一种新思路来列写偏导方程,从而在状态估计和潮流计算的处理中根据零支路两侧的相关数据建立对应的雅克比矩阵行。实践证明,该方法提高了数值稳定性,计算结果也更合理。     

一种牛顿潮流算法收敛性定理的应用研究

牛顿拉夫逊(NR)潮流算法是电力系统潮流计算最常用的算法之一,由于NR法具有平方收敛的特性,收敛速度较快,但它对初值选取的要求较高,初值选取对NR法的收敛性能有很大的影响.针对这一问题,分析了一种牛顿潮流算法的收敛性定理,运用此定理可解决因为初值选取不当而造成的潮流发散问题.此外,该定理可进一步评估选择的初值能否保证N...     

Fast computation and stable convergence technique for unbalanced load flow calculation in large‐scale systems

This paper presents a new method of unbalanced load flow calculation to improve complexity by the method of advanced symmetrical coordinates. Usually, the electric power system has been calculated only by the positive phase sequence component on the assumption that three‐phase transmission lines and loads are balanced. However, many ultrahigh‐voltage transmission lines are not transposed, and therefore mutual inductances cause negative sequence currents in the trunk transmission system. Negative sequence currents cause heating of generators and transformers, and therefore the three‐phase sequence component should be calculated accurately. We examined the fast computation and good convergence performance of unbalanced load flow calculation by models of three‐phase transmission lines, transformers, and loads. The proposed method is not the phase coordinate system but the method of symmetrical coordinates. This technique decreases numerical complexity by the use of a simplified Jacobian matrix. The convergence performance of this method is inferior to that of the usual Newton–Raphson method. As a consequence, the problem of poor convergence performance is alleviated by a technique for the newly developed deceleration Newton method. © 2010 Wiley Periodicals, Inc. Electr Eng Jpn, 174(1): 17–24, 2011; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.21034     

多平衡机潮流计算在调度员潮流中的应用

在调度员潮流中。多平衡机潮流计算比常规潮流计算更加符合电力系统的实际情况。计算结果更为准确。围绕系统不平衡功率的计算,提出了多平衡机潮流计算的三种算法：静态法、准动态法和基于动态潮流理论的动态法。并对每一种算法进行了详细介绍。平衡机群中各平衡发电机进行不平衡功率的分配可以采取多种分配方式。且需要考虑发电机有功出力的限制。对照IEEE14节点标准系统的测试结果表明本文的计算方法是有效、可行的。     

浅谈用FOXPR08．0开发电力系统潮流计算教学软件

以牛顿-拉夫逊法为例，说明了使用Visual Foxpr08．0制作电力系统潮流计算软件的过程，从而实现了电力系统潮流计算微机化。最后给出了一个算例，并将计算结果与PSASP计算结果进行对比，说明此潮流计算软件可用于教学实践与科学研究中，具有一定的实际意义。     

Elimination of floating nodes for load flow calculation

Most approaches aiming at reduction of the power flow computation time approximate the Jacobian matrix. Thus, the convergence is degraded compared to the conventional Newton method. This paper proposes a new approach for reducing the processing time by considering the fact that half of the nodes in real power systems are floating nodes that can be removed. In the conventional reduced matrix approach where the floating nodes are removed, the sparsity is lost. The method in this paper does not remove all of the floating nodes but keeps some nodes by using an optimal criterion for keeping the sparsity. The criterion is to indicate the minimum number of elements in the reduced matrix. This method has been applied to a 1000‐node test system. It was verified that the number of elements of the Jacobian has been reduced to about one‐half that of the conventional matrix. And computation time has been remarkably improved without sacrificing the convergence characteristics for the power flow computation. © 1999 Scripta Technica, Electr Eng Jpn, 129(2): 22–30, 1999     

基于Copula函数及Rosenblatt变换的含相关性概率潮流计算

随着风电渗透率的增加,在考虑风电出力随机性和间歇性对配电网影响的同时,风电场间风速的相关性应予以考虑。将Rosenblatt变换与Copula函数相结合以处理风电场间复杂的非线性关系,提出一种基于Copula函数及Rosenblatt变换的概率潮流半不变量算法。所提方法能准确捕捉到输入变量间的非线性相关关系,且具备半不变量法计算效率高的优点。以IEEE33节点网络接入风电场对所提方法进行测试。结果证明了所提方法的有效性、准确性和实用性,所提方法计算结果较考虑线性相关性算法的计算结果更接近实际运行情况。     

考虑电源与负荷间存在非正定相关性的概率潮流计算方法研究

随着电动汽车等新型电力系统负荷类型的出现,电源和负荷间的相关性日趋复杂,针对利用Cholesky分解完成概率潮流计算会受电力系统电源和电力系统负荷之间相关矩阵影响的问题,即随着相关矩阵维度的增加相关矩阵变为非正定,最终导致潮流计算无法进行的问题。文章提出一种新颖的处理相关性矩阵非正定的半不变量法,将修正Barzilai-Borwein梯度法与Nataf变换相结合,解决变量间相关矩阵非正定问题,并在IEEE-33节点系统中分析新型电力系统各类电源和负荷相关性对计算结果的影响,验证文章所提方法准确性。     

Visualization of results of load flow calculation and dynamic simulation

This paper proposes graphical representation methods of static and dynamic characteristics of power systems. The methods use the computed results of load flow calculation and dynamic stability calculation. This work develops three kinds of representation methods using maps and animation which are sequential graphical representation of maps based on dynamic stability calculation. Conventionally the results of load flow calculation and dynamic stability calculation are represented and comprehended using load flow maps or dynamic swing curve. However, quick and effective comprehension of power system characteristics by such conventional representation methods is becoming more difficult as power systems to be analyzed are becoming larger and more complicated, especially in power systems with many loops or grids. Graphical representation using the proposed methods makes it easy to understand the static and dynamic characteristics of power systems quickly and comprehensively. In addition to these methods, this paper proposes a heuristic logic that makes it possible to draw maps automatically. It is very convenient to apply these methods to arbitrary power systems even if their constitutions or characteristics are not well known.     

潮流计算收敛性问题研究综述

阐述了研究电力系统潮流不收敛问题的重要意义,分析了潮流计算不收敛的两种可能性:潮流病态和潮流无解,然后分别从这两个方面进行了综述。文中通过对已有研究方法的比较,总结了其中的不足,并提出几点建议完善潮流计算不收敛问题的研究,最后指出了以后的研究重点。