【作者】 邱威；

【导师】 张建华；

【作者基本信息】 华北电力大学 ， 电力系统及其自动化， 2012， 博士

【摘要】 有功优化调度是保证电力系统安全、经济、节能、高效运行的重要环节。近年来,能源危机和环境污染问题日益严峻,电网大停电事故频繁发生,传统的以提高经济效益为单一目标的有功优化调度已经不能满足新形势下电网调度运行的需求。在此背景下,本文针对考虑间歇性能源接入和电网运行安全的多目标有功优化调度问题展开研究,主要工作归纳如下。建立了求解电力系统多目标优化问题的一般框架。求解过程分为两个阶段,在第1阶段,提出一种自适应多目标差分进化算法来获取问题的帕累托(Pareto)最优解集,为各目标函数之间的权衡提供丰富的信息；在第2阶段,若Pareto最优解的数量较多,则首先采用聚类方法对Pareto最优解集进行分类,进而根据电力系统运行特性或应用多属性决策方法辅助决策者选择出折中方案。针对大规模风电接入对电力系统运行带来的不确定性因素,建立了基于机会约束规划的含风电场环境经济调度的随机优化模型。该模型采用威布尔分布描述风电出力的概率特性,以降低燃料成本和污染气体排放量为目标函数,引入正、负旋转备用约束以应对风电出力预测误差给系统调度带来的影响。利用风电出力的分布函数将随机模型转化为确定性模型进行求解。算例结果表明,所提环境经济调度策略可实现风电并网系统运行的经济性和清洁性综合最优。为避免电动汽车规模化应用后给系统运行带来的负面影响,建立了计及插电式混合动力汽车(Plug-in Hybrid Electric Vehicles,PHEVs)接入的动态优化调度模型。该模型将调度周期内各时段的PHEVs充电功率和燃煤机组出力作为决策变量,以降低燃料成本和日负荷曲线方差为目标函数,并引入考虑PHEVs行驶特性的约束条件。10机测试系统的计算结果表明,PHEVs有序充电可起到削峰填谷的作用。此外,算例中还探讨了PHEVs接入后的电力系统节能减排措施。针对电网运行中面临的随机故障以及传统确定性安全准则的缺点,将风险理论引入到有功优化调度中。从支路过载和节点电压越限的角度定义运行风险指标,采用效用函数度量故障后果以反映不同故障间的相对严重程度。以此为基础,建立了基于运行风险的经济调度模型。该模型以降低燃料成本和运行风险为目标函数,以系统N安全准则为运行约束条件,并在预想故障集中考虑了发生概率极小、后果却十分严重的多重故障。IEEE RTS-79测试系统的计算结果表明所提调度方法能给出全面的关于系统运行风险水平的量化信息,并且可辨识出电网中的薄弱环节。鉴于继电保护的不正确动作是导致电压崩溃的重要因素,建立了考虑距离保护动作特性的电压稳定约束最优潮流模型。该模型以降低燃料成本、有功网损和提高静态电压稳定裕度为目标函数,并计及距离Ⅲ段保护动作裕度约束。IEEE30节点测试系统的计算结果表明所提控制策略可有效降低重载网络中距离Ⅲ段保护不正确动作的风险。更多还原

【Abstract】 Active power dispatch is one of the most important parts to ensure the security, economy, energy conservation, and high efficiency of power system operation. In recent years, energy crisis and environmental pollution are growing concerns, many blackouts happened around the world. The traditional optimal active power dispatch method which only considers minimizing the total fuel cost can not meet the requirements of power grid dispatching operation in the new situation. Therefore, multi-objective optimal active power dispatch with intermittent energy integration and operation security is analyzed in this dissertation.A general framework for solving power system multi-objective optimization problems is proposed. The solving process involves two stages. At the first stage, a self-adaptive multi-objective differential evolution algorithm is proposed to obtain the Pareto front, the valuable tradeoff information between objectives can be provided. At the second stage, if the Pareto-optimal set is large, the data clustering method is applied first to classify the Pareto optimal solutions into several clusters with similar properties. Then, within each cluster, the compromise solution is selected according to the operation characteristics of power system or through using multiple attribute decision making theory.Integrating the power generated by large-scale wind farm into power grid introduces an extra factor of uncertainties for power system operation. Based on chance-constrained programming, an environmental/economic dispatch model is formulated for the system incorporating wind farm. In this model, Weibull distribution is used to describe the stochastic behavior of wind power, minimizing both the fuel cost and emission of atmospheric pollutants of thermal generators are considered as objective functions, the up spinning reserve and the down spinning reserve constraints are introduced to deal with the influence of wind power on economic dispatch. According to the cumulative distribution function of wind power, the stochastic optimization problem is transformed to a deterministic one. Numerical experiments demonstrate the effectiveness of the proposed dispatching approach.The widespread adoption of plug-in hybrid electric vehicles (PHEVs) will bring new challenges to the secure and economical operation of power systems. A multi-objective dynamic economic dispatch model with large-scale PHEVs penetration is formulated to minimize the fuel cost and to improve the load characteristic. In this model, the PHEVs charging loads and the generator outputs of each time period are selected as decision variables, the driving behavior of PHEVs is taken into account. To demonstrate the effectiveness of the proposed method, the generation scheduling problem is performed on the ten-unit system. At last, the emission-reduction strategies of PHEVs-penetrated power systems are discussed.In view of the uncertainties exist in the operation of power grid and the drawback of traditional deterministic security criterion, the risk theory is introduced into the optimal generation dispatch. The operation risk index is defined based on branch overload and bus voltage violation, the utility function is employed to measure the severity in order to reflect relative severity between different contingencies. Risk-based multi-objective economic dispatch model is formulated, minimizing both the operation risk and fuel cost are considered as objective functions, and the normal state constraints are taken into account. In addition, the post-contingency set comprises both single fault and multiple faults. The proposed generation dispatch approach is tested on IEEE RTS-79test system, the results obtained show that the quantitative index that reflects security level can be provided, and vulnerable parts of power grid can be identified.Since undesirable protective relay operation played a major role in voltage collapse, a voltage stability constrained optimal power flow model considering the operation characteristics of distance protection is formulated. Minimizing the fuel cost, active power loss and maximizing the static voltage stability margin are selected as objective functions. Operation margin of zone3impedance relay constraint is included in the model. Numerical results on IEEE30-bus test system are provided to validate the accuracy of the proposed model, the risk of mal-operation can be reduced in stressed power systems.更多还原