一种不对称配电网三相潮流快速算法

为了适应在线潮流计算对速度的要求,阐述了一种配电网潮流快速算法,并通过增加内电势点对其作了一些改进,使其对实际运行中的各种三相网络不对称情况都能进行快速准确的计算。该方法只需要两个成熟的矩阵———母线注入到支路电流和支路电流到母线电压矩阵以及一个简单的矩阵乘法就能完成潮流的快速计算。用M atlab语言实现了该算法。并通过算例将其与牛顿法作了比较,测试结果证明了该算法的高效性和准确性。     

配电网三相潮流算法的研究

提出了配电系统三相潮流求解的一种新方法：直角坐标增广形式的牛顿法。为了包含尽可能多的线性方程，将节点方程和母线约束都加以保留，然后用牛顿法求解以节点电压和注入电流为状态变量的增广方程组。另外，提出了一种简单有效的初值配置方法。试验系统的计算结果表明了该方法是鲁棒和有效的。     

基于前推回代的配电网潮流改进算法

提出了一种新的基于前推回代的配电网络潮流算法。该算法能较好地处理弱环网接线方式。考虑了两种不同类型的环网接线方式。并且易于多馈线网络。采用戴维南敏感阻抗矩阵分析法把环网处理和PU节点的处理统一起来,简化了分析过程,使得该算法的计算效率大大提高。理论分析和实例证明该算法快速有效,符合配电网络的分析实际需要。     

配电网三相潮流计算

针对我国目前配电自动化实施情况和实际配电网中存在负荷严重不对称的特点，提出三相配电网络实时潮流计算方法。并对北京回龙观居民小区配电自动化系统中某10kV配电线路某时刻的实测数据作了实时计算，计算结果表明采用三相潮流计算比常规潮流计算更能反映网络的实际运行状态。     

一种新的配电网三相潮流算法

提出一种用于不平衡辐射状配电网的三相潮流计算方法。根据配电网的辐射状结构特点,将分支线作为配网结构的基本单元,把馈线分支首节点的电压、电流表示为分支末节点电压、电流的函数．重新建立潮流方程,使方程的数目与分支线数目成正比,大幅度减少方程式和变量的数目。并且根据配电网的特点近似简化雅可比矩阵．以实现解耦。建立了单相系统模型和三相系统模型,给出了潮流的解耦算法。相对于传统计算方法未知数正比于母线数目,可以大幅度减少方程数,缩短计算时间,特别适用于大规模配电系统。     

三相不平衡配电网的潮流故障统一分析方法

摘要： 针对配电网的辐射状和弱环网以及三相不平衡的特点，在前代回推的基础上，提出了一种利用多端口混合补偿技术的三相潮流和故障计算的统一分析方法。提出了对各种故障具有统一形式的故障端口补偿电路，并且该方法在电网的正常和故障两种情况下具有统一的计算公式和迭代步骤。因而，故障计算与普通潮流计算具有相同的收敛性。并且，计算模型中可以考虑详细的负荷模型，提高了故障电流计算值的精确度。数值算例表明该方法具有很高的效率和计算精度，完全可以应用于实时控制系统。     

复杂配电网潮流的降规模计算

为了减少大规模配电网潮流分析的计算量,探讨了电压降和线损的简化计算方法.文章证明了当流过馈线段的末梢节点的功率不为零时,用双方向等效电压降模型计算沿线电压降时能得到准确的结果,而用双方向等效线损模型计算时却不能得到准确的线损结果.因此提出了一种可有效地避免线损计算误差的方法.该方法是一种利用双方向等效电压降模型的计算结果进一步计算馈线沿线各负荷点的电压,并用递推方法计算该馈线段上各条支路的线损的方法.采用文中提出的方法可大大减少参与迭代计算的节点数,而且各负荷点的电压以及配电网的线损都不需要迭代就可以直接计算得到,从而精确得到整个配电网的线损.经对198节点的实际配电网的计算,验证了该方法的有效性和精确性,且比等效线损模型优越.     

一种含分布式发电系统的三相配电网潮流直接算法

提出一种基于道路矩阵的三相不平衡配电网潮流直接算法,该算法充分利用配电网络的结构特点,建立了节点电压与注入电流的关系矩阵,实现了潮流的直接计算。基于PV节点的特性,推导了PV节点网络的有功电流和无功电流关系,并提出了一种新的处理PV类型分布式发电的方法。将该方法引入到三相系统潮流计算中,保证了PV节点幅值为预设定值（假定无功功率没有越界）。6母线和69母线系统算例验证了该方法简单实用,潮流计算时间短和迭代次数少,具有很好的通用性。     

不对称三相潮流的对称分量分析法

本文提出了在对称分量坐标中不对称三相潮流的两种求解方法——隐式阻抗矩阵法和解耦—补偿法。这两种方法都能充分利用对称分量坐标中对称元件,诸如发电机、变压器等的解耦特性,提高三相潮流的解算速度。解耦—补偿法则进一步利用不对称输电线路三序之间的弱耦合特性,通过对三序间弱耦合的补偿,实现三序之间的解耦求解,该法还适合于并行计算。算例表明,本文提出的方法具有较快的计算速度和良好的收敛特性。     

配电系统不对称潮流计算的实用算法研究

根据配电系统的特点,推导出一种实用的配电系统三相不对称潮流计算方法,并详细分析了该算法的计算机实现过程。实例计算表明,该算法对配电网不对称潮流的计算有较好的收敛特性和较快的收敛速度。     

Consideration of input parameter uncertainties in load flow solution of three-phase unbalanced radial distribution system

In this paper, a technique based on interval arithmetic is presented for considering the uncertainties of the input parameters in the power flow solution of three-phase unbalanced radial distribution systems. The uncertainties in both the load demand and the feeder parameters have been considered. The results obtained from an interval arithmetic-based power flow solution have been compared with those obtained from repeated load flow simulations.     

A fast and efficient load flow technique for unbalanced distribution system

This paper presents a fast and efficient load flow technique for unbalanced distribution system. The proposed load flow technique is derived by promulgating the concept of conventional backward forward sweep (BFS) technique of power flow study for distribution system. The proposed technique employs a novel load-impedance matrix (LIM) to calculate the bus voltages in a single step unlike the conventional BFS approach which involves two separate steps (backward sweep and forward sweep) to perform the same and this improvement is claimed as the novelty of this work. This distinctive feature makes the proposed algorithm faster in operation. Nodal voltages, at any iteration, may be calculated, directly, from the values obtained in the previous iteration by utilizing LIM. A simple concept of set theory is adopted here to construct the LIM. Special treatments are also included in this method to analyze weakly meshed systems. The proposed technique is flexible enough to accommodate any sort of changes in the existing network topology through LIM. It is tested on different three-phase balanced and unbalanced radial distribution systems as well as weakly meshed networks for load flow study. A separate case study is also presented to check the validity of the proposed load flow technique for various transformer connections. The obtained results demonstrate the effectiveness of the proposed technique. Furthermore, performance comparison reveals that the proposed algorithm is, computationally, faster and robust than the conventional power flow techniques reported in the recent state-of-the-art literatures.     

Simplified three-phase lateral and feeder models for fast distribution system calculations

This paper introduces three simplified three-phase lateral models for fast distribution system calculations. The models can also be applied to model a feeder with short laterals, whose impedances are negligible. These models are formulated using three lumped individual phase loads to represent single-phase, three-phase unbalanced, and nonuniformly distributed loads along a lateral or feeder. Proposed voltage-drop and line-loss models are developed to accurately simulate the total series voltage drop at the end and the total copper loss of a given lateral, respectively. A hybrid model is then developed to simulate both voltage drop and line loss accurately. All of the proposed models are used to represent the unbalance features of a physical distribution system in which various transformer connections are presented. The proposed models are applied to a physical feeder of Taiwan Power Company (Taipower). The simulation results show that it is possible to simplify complicated laterals or feeders to simple equivalent models in the calculations of voltage profiles and line losses with negligible error, even if there are various transformer connection schemes in the lateral or feeder.     

A unified three-phase transformer model for distribution load flow calculations

This paper provides a unified method to model three-phase transformers for distribution system load flow calculations, especially when the matrix singularity caused by the transformer configuration arises. This paper shows that the singularity appears only in certain transformer admittance submatrices and only in certain transformer configurations. The unified method presented in this paper can solve the voltage/current equations in the forward/backward sweep algorithm for various types of transformer configurations, whether or not the corresponding admittance submatrices are singular. Comprehensive comparisons have been made between the proposed approach and other methods. Test results demonstrate the validity and effectiveness of the proposed method.     

一种新的保留二阶项的配电网快速潮流算法

在直角坐标系中,潮流方程是一个典型的多变量非线性二次型式的代数方程组.利用此特征并充分结合配电网的特点,提出了一种新的快速配电网潮流计算方法.该方法首先对二次型式的潮流方程进行严格的Taylor级数展开,然后利用Maclaurin.Newton方法,将上述非线性矩阵方程变换成常见的线性矩阵方程,从而最终求出配电网的潮流.利用IEEE 33节点、145节点配电系统,对导出的算法进行了验算和相关对比测试.结果表明,所提出的算法比已有的保留二阶项类算法具有更好的收敛特性,因而是一种较好的配电网潮流计算方法.     

基于坐标旋转变换的配电系统快速解耦潮流计算方法

配电系统中各支路的电阻与其电抗的比值较大,因此,经典的快速解耦潮流计算方法不适用于配电系统潮流计算。提出了一种坐标旋转变换方法,并将这种变换方法与经典的隐式Zbus高斯方法相结合,导出了配电系统的解耦潮流计算方法。以IEEE 33节点、IEEE 69节点和一个实际的145节点配电系统为例,对提出的解耦潮流算法进行了测试。结果表明,所提出的解耦方法不影响经典的隐式Zbus高斯方法的收敛性,因而是一种高效、实用的快速潮流计算方法。     

复杂配电网络三相实用潮流算法

基于配电网放射状结构、网络拓扑约束特点和戴维南多端口等值电路、高斯—赛德尔PV节点迭代等补偿技术 ,并结合拓扑扩展和矩阵增广的数值方法提出一种解决复杂配电网络的实用潮流计算方法。实验表明 ,本文算法是有效的。     

复杂配电网络三相实用潮流算法

基于配电网放射状结构、网络拓扑约束特点和戴维南多端口等值电路、高斯—赛德尔PV节点迭代等补偿技术,并结合拓扑扩展和矩阵增广的数值方法提出一种解决复杂配电网络的实用潮流计算方法。实验表明,本文算法是有效的。     

Application of quasi-Newton method to load flow studies and solution of load flow during three-phase fault

Newton's method, because of its quadratic convergence, is mathematically the most preferable of the several known methods for the solution of load flow problems. However, this method is not absolutely convergent for ill-conditioned problems. This paper presents a modification to Newton's method designed to reduce the number of function evaluations required in the solution of the load flow problem. It is a variation of Newton's method, in which the partial derivatives are replaced by difference equations, which is capable of giving significant improvement for routine load flow studies.In addition, an algorithm using the Freudenstein-Roth technique is incorporated in the program. This technique, which is essentially a parameter perturbation procedure, together with the quasi-Newton method, envisages a fast and accurate solution for load flow during a solid three-phase short-circuit.