电力系统区域间最大功率交换量计算

本文介绍了一种以连续型潮流计算方法为基础的电力系统区域间最大功率交换量计算方法,该方法可以计及线路过负荷、节点电压赵界及潮流解鞍点分叉等静态安全性约束条件的影响,虽计算速度尚不能满足在线应用的要求,但可以作为区域系统间功率交换能力离线分析的有效手段。     

电力系统区域间功率交换能力的研究（二）最大交换功率的模型与算法

以连续型潮流计算方法为基础,建立了描述互联电力系统区域间功率交换能力的数学模型,介绍了计算区域间最大功率交换量的方法。这种方法既可以考虑诸如电压水平、线路及设备过负荷等静态安全性约束条件,也可以考虑由于潮流方程解的鞍型分叉导致的电压稳定性约束,同时还可以考虑动态约束条件的影响,因而具有重要的实用价值。     

电力系统区域间功率交换能力的研究（二）：——最大交换功率的模型？…

以连续型潮流计算方法为基础,建立了描述互联电力系统区域间功率交换能力的数学模型,好计算区域间最大功率交换量的方法,这种方法既可以考虑诸如电压水平、线路及设备过负荷等静态安全性约束条件,也可以考虑由于潮流方程解的鞍型分叉导致的电压稳定性约束,同时还可以考虑动态约束条件的影响,因而具有重要的实用价值。     

电力系统区域间功率交换能力的研究（二）最大交换功率的模型与算法

以连续型潮流计算方法为基础,建立了描述互联电力系统区域间功率交换能力的数 学模型,介绍了计算区域间最大功率交换量的方法。这种方法既可以考虑诸如电压水平、线 路及设备过负荷等静态安全性约束条件,也可以考虑由于潮流方程解的鞍型分叉导致的电压 稳定性约束,同时还可以考虑动态约束条件的影响,因而具有重要的实用价值。     

考虑ULTC和SVC等影响的功率交换能力的分析与计算

建立了计及发电机无功功率限制、有载调压变压器(ULTC)和无功补偿装置(SVC)对电力系统区域间功率交换能力影响的系统分析数学模型,提出了计及发电机无功功率极限、ULTC和SVC等影响的区域间功率交换能力的分析与计算方法,并以实际系统为例进行了大量的仿真分析计算.计算结果表明:当只计及发电机无功限制,或只计及ULTC时,区域间功率交换能力将下降;当同时计及上述3种影响因素的影响时,将有利于提高区域间功率交换能力.这为探索提高系统区域间功率交换能力的措施提供了分析方法和决策依据.     

基于多重约束的“三华”特高压电网功率交换极限评估

随着特高压交/直流混合电网的逐步建成,大区电网间必将存在大功率传输。为了确保电网在其安全稳定极限内正常运行,提出基于多重约束条件下的大区电网间功率交换极限计算方法。该方法采用基于改变的区间交换功率下的频率响应特性分析、静态电压稳定分析、以及暂态能量函数分析对系统功率交换能力进行评估,对比满足各个约束条件的功率交换极限,确定约束系统断面功率交换能力的决定因素,得到多重约束条件下的功率交换极限,并以此来指导区间功率分配方案的制定与优化。对"三华"电网的仿真分析表明,该研究所提方法能在考虑多重约束条件前提下快速准确地计算出电网的功率交换极限,计算结果误差均<6%,满足工程实际的精度要求,且该规划模型在最大交换功率下其特高压输电线路的输送功率在热稳定限制以内。     

基于最优潮流并计及静态电压稳定性约束的区域间可用输电能力计算

可用输电能力(ATC)是衡量电力系统在安全稳定运行的前提下区域间功率交换能力的指标。文中基于最优潮流(OPF)方法，建立起符合电力市场交易机制的ATC计算模型，其中考虑到输电线路故障对系统静态电压稳定性的影响，加入线路N-1故障时广义参数化形式的潮流方程及相应的不等式约束条件，使系统在故障时仍有负荷裕度，以保持电压稳定；以支路功率和系统负荷裕度之间的灵敏度指标进行预想故障选择，并用原对偶内点法计算得到输电线路N-1安全约束下的区域间可用输电能力。IEEE30和IEEE118节点系统算例表明该模型和算法的正确性与有效性。     

电力系统区域间功率交换能力的研究（一）：连续型方法的基本理？…

格为电力系统区域间功率交换能力研究的基础，重点介绍了连续型潮流计算方法的数学理论，即非线性系统分析中的参数化连续数值方法。     

电力系统区域间功率交换能力的研究(一):连续型方法的基本理论及应用

作为电力系统区域间功率交换能力研究的基础,重点介绍了连续型潮流计算方法的数学理论,即非线性系统分析中的参数化连续型数值方法.总结了该方法的原理、算法及其在电力系统中的应用.连续型潮流计算方法与常规潮流计算方法相比,其最大的优点就是可以克服在潮流解曲线鞍型分叉点处由于常规雅可比矩阵奇异而导致的计算困难,这一方法特别适用于最大功率交换能力的求解.     

高比例风电电力系统考虑频率安全约束的机组组合

高比例风电接入电力系统导致转动惯量和一次调频能力降低,功率扰动下的频率安全问题凸显,机组组合中需要考虑频率安全约束。首先提出了一种简单实用的频率安全约束条件,当系统满足该约束条件时,给定功率扰动下的最大频率偏差将保持在设定限值内。将该约束条件纳入机组组合模型,同时考虑风电出力为预测区间上下限值时系统仍能够承受给定的功率扰动,建立了考虑风电功率不确定性与频率安全约束的机组组合模型。仿真结果证明,所提出的机组组合模型考虑了风电功率的不确定性,同时也能满足系统发生大功率扰动下的频率安全需要。     

An evaluation method for power transfer capability enhanced by lightning countermeasures

Various countermeasures are taken against lightning faults in power transmission lines to decrease their occurrence and improve transmission reliability. However, how much they enhance the power transfer capability has not yet been quantitatively evaluated. The conventional deterministic approach, which is widely used in power system planning methodology, is inadequate to deal with this issue. This paper proposes a new method for numerically defining the power transfer capability enhanced by countermeasures against lightning. The proposed method is based on a probabilistic approach in which several fault patterns are taken into consideration with their occurrence frequency and maximum transferable power. This paper also gives an example application of the proposed method to a model trunk transmission system. The effect of a third overhead ground wire on the increase of transfer capability of a 500 kV transmission line has been quantitatively evaluated.     

Two-point estimate method for quantifying transfer capability uncertainty

A two-point estimate method is proposed in this paper to assess the power transfer capability uncertainty. This paper assumes that the uncertainty of the line parameters and bus injections involved in transfer capability calculations can be estimated or measured and shows how to estimate the corresponding uncertainty in the transfer capability. Instead of using a large number of simulations as required in the Monte Carlo approach, for a system with n uncertain parameters, the two-point estimate method uses 2n calculations of transfer capability to quantify the uncertainty. The proposed method uses a numerical method to calculate the moments of the transfer capability. The moments are then used in the probability distribution fitting. Using the obtained transfer capability uncertainty information and a desired level of reliability, an adequate transmission reliability margin can be determined for each transmission service. The proposed method can be used directly with a deterministic computer program and it does not require derivatives of the transfer capability. Test results of the proposed method are compared with those obtained from the Monte Carlo simulations and a truncated Taylor series expansion method.     

Probabilistic approach to available transfer capability calculation

This paper suggests a probabilistic approach to calculate available transfer capability in the interconnected network. Calculation of available transfer capability is complicated because it involves determination of total transfer capability, transmission reliability margin and capacity benefit margin.In the suggested available transfer capability quantification method, total transfer capability is determined by the continuation power flow process. Transmission reliability margin and capacity benefit margin are evaluated by probabilistic load flow and Monte Carlo simulation, respectively.Proposed method is applied to a modified IEEE 72-bus 3-area system to calculate available transfer capability on two different time spans. Results of the case study show that suggested probabilistic approach can offer operational flexibility for system operators to consider system and market uncertainties.     

含有风电发电机组可用输电能力新算法的研究

阐述了含有风电发电机组的潮流计算模型,提出将改进蚁群算法、变邻域搜索算法和差分进化算法相结合应用到可用输电能力研究中,该算法克服了陷入局部最优解的缺点,并提高了寻优的效率、全局的寻优能力和结果 的稳定性.以IEEE30节点标准系统作为算例对输电网可用输电能力进行仿真计算,计算结果表明本文提出的算法具有合理性和可靠性.     

Sensitivity of transfer capability margins with a fast formula

Bulk power transfers in electric power systems are limited by transmission network security. Transfer capability measures the maximum power transfer permissible under certain assumptions. Once a transfer capability has been computed for one set of assumptions, it is useful to quickly estimate the effect on the transfer capability of modifying those assumptions. This paper presents a computationally efficient formula for the first order sensitivity of the transfer capability with respect to the variation of any parameters. The sensitivity formula is very fast to evaluate. The approach is consistent with the current industrial practice of using DC load flow models and significantly generalizes that practice to more detailed AC power system models that include voltage and reive power limits. The computation is illustrated and tested on a 3357 bus power system     

基于输配全局的城市电网供电能力研究

提出一种基于输配全局的城市电网供电能力分析模型。采用基于直流潮流的线性规划模型对城市电网输电网络供电能力进行求解并将其作为系统上层约束;将传统配电网模型细化至中压馈线,分别构建高、中压配电网供电能力模型;计算N-1安全约束下高压配电线路、中压配电变压器及中压配电线路在不同转供方式下对应的最大供电能力,选取其中最小值作为系统最大供电能力。算例结果表明：基于输配全局的分析方法可以有效量化输电网对城市电网供电能力的影响,同时根据不同转供方式下的供电能力差异能够直观地对变压器故障情况下的负荷转移方式做出选择,验证了所提模型的有效性。     

电压型ICPT系统功率传输特性的分析与优化

针对感应耦合电能传输(ICPT)系统功率传输能力和效率优化问题,对电压型ICPT的功率传输特性进行了分析.通常认为提高系统的谐振频率能提高系统的功率传输能力,但通过本文的研究发现,对于采用SS拓扑的ICPT系统,谐振频率的选取存在一个优化的取值,而对于采用SP拓扑结构的ICPT系统,在一定的频率带上,谐振频率的增加对系...     

New two chamber transfer switch for 6500 A commutation current

HVDC transfer switches are used in different locations in electrode lines of HVDC transmission systems for their reconfigurations. They have to carry and commutate currents to the overload currents of HVDC transmission systems, which increased to 6,400 A in the past years. Common designs of transfer switches use combinations of several switching units connected in series and parallel. This paper describes the design and development of a new DC commutation switch with two switching units only, but it is able to carry currents up to 10,000 A and has an actual tested commutation capability of 6,500 A.