一种考虑网络损耗及线路过负荷的火力发电机起停计划方法

以面向实际应用为目的，提出了一种考虑输电网络损耗及线路过负荷约束的火力发电机起停计划方法。首先用动态规划法建立一个不含约束条件的初始解，然后运用启发式方法对初始解进行修正使之逐个满足各约束条件得到运行可能解，并通过修改各发电机的起动优先顺序使此过程反复进行直至得到（准）最佳解。在此过程中引入最优潮流计算考虑输电网络损耗及线路过负荷等网络因素对发电机起停计划的影响成为可能，并提出一种调节发电机出力和改变发电机起停计划相结合的消除线路过负荷的方法。在一个8机44母线的测试系统上对提案方法进行了各种条件下的试算，验证了所提出的方法对解决考虑网络因素影响的发电机起停计划问题有效性。计算结果还表明：不仅线路过负荷起停计划问题的有效性。计算结果还表明：不公线路过负荷约束，网络损耗也对发电机起停 计划有较大影响。     

配电网络潮流计算实用算法

介绍了传统的电力系统潮流计算方法及配电网络潮流计算的难点,根据高压网和配电网潮流计算的特点,提出了配电网络潮流计算的实用算法,并以实例验证了该算法的可行性。     

一种机组优化组合问题的遗传算法

火力发电厂的发电机组优化组合问题具有高维数、非凸、离散、非线性、多约束的特点,增加了求解的复杂性。讨论了机组优化启停的遗传算法,通过可行性检查使初始解群中的所有个体都是可行解,也使求解过程中建立了一种从不可行解域到可行解域的映射关系,这样可以大大减少无效的遗传搜索过程。实例计算表明,该方法收敛性好,适应性强,计算速度快,能够使计算的结果更加有效地接近全局最优解。     

多电压级配电网络重构的实用算法

提出了多电压级配电网络重构的实用算法。通过把全国网络参数用标幺值表示,变压器用Ⅱ型等值电路,把接地支路看做负荷处理后,使得多电压级的网络在形式上与单一是压网络相似。在网络重构中考虑了电容补偿的投切和变比的选择。在具体求解方法上,把一个多环网的复杂网络重构问题分解为各个单环网的重构问题,通过递归算法协调,即在重构单环网的顺序选择上,使刚刚重构过的单环网也参加了选择,这就排除了各个单环网的开合顺序,保证整个网络重构的优化解。在单环网的重构中按电流经济分布时,将流过电流绝对值最小的且没有支路电流过载的开关作为断开开关。     

考虑输电线路动态增容的增强型安全约束最优潮流

在复杂内外部风险的影响下,输变电设备的随机故障已成为影响电网安全运行的重要因素。针对现有安全约束最优潮流存在的灵活性或安全性不足的问题,提出了一种增强型安全约束最优潮流(ESCOPF)模型,采用输电线路动态增容技术,保证电网在预想事故发生后至校正控制生效前的运行安全性。并给出了一种基于Benders分解的求解算法,将原问题分解为预防控制主问题、动态增容校验子问题和校正控制可行性校验子问题。通过不断向主问题返回Benders割修正机组发电计划,最终得到满足所有子问题校验的最优发电计划。算例分析结果表明,ESCOPF模型能够充分利用线路输电能力,扩大电网安全运行范围,从而提升系统运行的经济性。     

一种配电网的实用潮流算法

在分析配电网络结构特点和现有配电网潮流计算方法优缺点的基础上 ,提出一种有效的配电网潮流算法。该算法基于叠加原理 ,把网络节点电压看作是配电网根节点和配电网负荷共同作用的结果 ;把配电网作为一个整体形成节点导纳矩阵 ,适用于弱环网运行的配电网 ,算法简捷实用。算例证明了该文方法的有效性     

一种配电网的实用潮流算法

在分析配电网络结构特点和现有配电网潮流计算方法优缺点的基础上,提出一种有效的配电网潮流算法.该算法基于叠加原理,把网络节点电压看作是配电网根节点和配电网负荷共同作用的结果;把配电网作为一个整体形成节点导纳矩阵,适用于弱环网运行的配电网,算法简捷实用.算例证明了该文方法的有效性.     

一种计算低压系统中三相电力潮流和短路电流的实用算法

概括介绍了低压系统中计算三相电力潮流和不平衡短路电流的一种实用相坐标算法。该方法可以模拟不对称负荷、中性线和冲击电压,所以网络方程组中包含以相坐标形式表示的中性线和接地导线的参数,大量计算数据证明,这种对不换位电缆参数和不平衡负荷电流效应的模拟是可行的。相对于传统的对称分量法等常规方法,此种方法可以得到更精确的结果。     

一种后／前代法在配电网络再构方面的应用

文章通过数据存储方式的改进,提出了一种便于网络再构,不依赖于节点和支 编号顺序的树状网潮流计算算法,并充分利用原有树状网的算法和数据,实现了环网的经济潮流计算。     

Unit commitment scheduling by Lagrange relaxation method taking into account transmission losses

Since the application of the Lagrange relaxation method to the unit commitment scheduling by Muckstadt in 1979, many papers using this method have been published. The greatest advantage of applying the Lagrange relaxation method for the unit commitment problem is that it can relax (ignore) each generator's output dependency caused by the demand–supply balance constraint so that a unit commitment of each generator is determined independently by dynamic programming. However, when we introduce the transmission loss into the demand–supply balance constraint, we cannot decompose the problem into the partial problems in which each generator's unit commitment is determined independently and have to take some measures to obtain an optimal schedule by the Lagrange relaxation method directly. In this paper, we present an algorithm for the unit commitment schedule using the Lagrange relaxation method for the case of taking into account transmission losses. © 2005 Wiley Periodicals, Inc. Electr Eng Jpn, 152(4): 27–33, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20119     

A method for unit commitment with transmission losses and flow constraint

Researches on the unit commitment with transmission network have been reported recently. However, most of these researches mainly discussed the security constrained unit commitment, while the relationship between unit commitment and transmission losses was not considered. However, from the standpoint of operating reserve for ensuring power supply reliability, a unit commitment considering transmission losses is required. Further, under the deregulation and liberalization of the electric power industry, not only the line's security but also transmission losses are expected to play an important role in calculating the network access charge, and unit commitment taking into account transmission losses is also desired from this viewpoint. In this paper, a unit commitment approach with both transmission losses and line flow constraint is presented. Based on a heuristic iterative optimization method, first, an initial schedule is created by using a successively decommitting unit approach that is proposed in this paper. Then, we determine constraints included in the unit commitment schedule by a heuristic iterative optimization approach, in which an algorithm able to get rid of line overload by DC optimal power flow is developed. Through numerical simulations on two test power systems, the effectiveness of the proposed method is shown. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 142(4): 9–19, 2003; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10116     

Unit commitment taking into account reactive power

In this paper, the Voltage Magnitude Constrained OPF (VMC‐OPF) algorithm to determine the reactive power injection from compensating equipment to load bus is developed. By introducing the proposed VMC‐OPF to the real power related Unit Commitment (UC) [1], a novel daily UC method taking into account the reactive power to secure bus voltage magnitude is presented. The Transmission Access Charge (TAC) and Ancillary Services Charge (ASC) are included in the objective function for considering costs of using transmission network and supplying reactive power to maintain the voltage. Using the proposed UC, the difference between two schedules based on benefit maximization and cost minimization is also discussed. To ascertain the effectiveness of the proposed UC method, we demonstrate various simulation results for a model power system of IEEE‐118 bus system. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 162(3): 17–26, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20590     

A study of a unit commitment problem with transmission constraints

Unit commitment problem is an optimization problem to determine the start‐up and shut‐down schedule of thermal units while satisfying various constraints, for example, generation‐demand balance, unit minimum up/down time, system reserve, and so on. Since this problem involves a large number of 0–1 type variables that represent up/down status of the unit and continuous variables expressing generation output, it is a difficult combinatorial optimization problem to solve. The study at present concerns the method for requiring the suboptimum solution efficiently. Unit commitment method widely used solves the problem without consideration of voltage, reactive power, and transmission constraints. In this paper, we will propose a solution of unit commitment with voltage and transmission constraints, based on the unit decommitment procedure (UDP) method, heuristic method, and optimal power flow (OPF). In this method, initial unit status will be determined from random numbers and the feasibility will be checked for minimum start‐up/shut‐down time and demand‐generation balance. If the solution is infeasible, the initial solution will be regenerated until a feasible solution can be found. Next, OPF is applied for each time period with the temporary unit status. Then, the units that have less contribution to the cost are detected and will be shut down based on the unit decommitment rules. This process will be repeated until suboptimal solution is obtained. The proposed method has been applied to the IEEE 118‐bus test system with 36 generating units with successful result. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 144(3): 36–45, 2003; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10187     

基于群论的三峡电厂机组负荷分配算法研究

水电站厂内经济运行是一项提高水能利用效率的节能措施。厂内机组负荷分配以耗流量最小为准则,一般用动态规划方法求解。三峡电厂机组数目较多,承担负荷较大,采用动态规划求解易出现维数灾问题。本文提出基于群论的机组组合降维方法,将三峡电厂机组按运行特性分组,基于Burnside计数定理计算本质不同机组运行状态组合数及相应运行状态组合,降维后再采用动态规划法进行时间-空间优化求解。将该模型算法应用于三峡电厂厂内经济运行,结果表明,该方法能够有效降低计算量,快速响应水电系统运行工况。     

一种求解机组组合问题的内点半定规划GPU并行算法

针对内点法求解机组组合问题的半定规划(SDP)模型时大规模线性方程组计算时间太长的问题,提出一种基于图形处理器(GPU)的Krylov子空间并行算法.该算法采用预条件处理的拟最小残差法(QMR法),并以矩阵分块技术为基础,在CSR存储格式下使用GPU实现Incomplete Cholesky并行预处理矩阵的计算.通过对不同规模线性方程组的计算分析表明,与传统的Cholesky直接法相比,QMR并行算法具有速度和存储优势,可获得良好的并行加速比.10～100机6个系统的仿真结果也表明,该SDP并行内点法在减少计算时间的同时可求得近似最优解.     

机组组合问题的罚函数法

机组组合问题是一个大规模的非线性、0、1变量混合整数规划问题 ,是一个难问题。以罚函数方法解决0、1变量整数规划问题是一个新的尝试。文中考虑包括发电机爬坡约束和时间约束等动态约束在内的多种约束条件 ,对机组组合问题的 0、1变量进行松弛 ,并在目标函数中增加一个惩罚函数项 ,将问题变换成一个非线性连续变量的规划问题 ,以SQP法求解。本算法经过一个简单的算例检验 ,说明是行之有效的。     

基于改进的逆序排序法的机组组合优化算法

文章提出了改进的逆序排序法来求解机组组合优化问题.该算法从可用机组全投入运行这一可行解出发,在每次迭代过程中优化一台机组在整个调度周期内的开停状况,以最小化总生产成本或总购电成本,直到连续两次迭代的目标函数值不再减小为止.该方法的显著优点在于计算不会振荡,迭代不会发散,且每次迭代的结果均为可行解.该算法在单机组优化过程中,以机组的最小启停区间而不是单个时段为研究调度对象,缓解了组合爆炸问题,明显地加快了计算速度.     

考虑输配协同的电网机组组合与技改计划联合优化模型

进行考虑输配协同的电网机组组合与技改计划联合优化,对于提高输配整体新能源消纳率、保障系统中短期可靠经济运行具有重要意义。分别构建输电网、配电网的机组组合与技改计划联合优化模型。针对中短期优化中新能源随机性较大的问题,采用机会约束规划进行处理并将约束转化为确定性约束。分析输配分立式优化、集中式协同优化、分布式协同优化求解模型的可行性,综合比较后采用基于目标级联分析法的分布式协同优化算法实现模型的输配解耦与并行求解。算例分析表明,所提模型能够合理安排输配电网的机组启停机状态及技改项目的施工计划,并验证了目标级联分析法对于解决输配协同优化问题的有效性。