在线暂态安全稳定评估的分类滚动故障筛选方法

为满足在线暂态安全稳定评估对计算时间的要求,提出了基于模式和裕度估算的在线暂态安全稳定故障筛选方法。分别基于上一轮在线暂态安全稳定评估结果中各个预想故障的暂态功角稳定、暂态电压跌落安全、暂态电压稳定和暂态频率偏移安全的裕度及模式信息,并结合各个故障安全稳定模式中相关元件的潮流变化和投/退等信息,估算出新一轮在线暂态安全稳定评估所对应的运行状态下各个故障的暂态安全稳定裕度,并确定其相应的安全稳定模式,从而筛选出本轮在线暂态安全稳定评估需详细计算的预想故障子集。通过对实际电网在线数据的仿真分析,验证了所述方法的有效性和实用性。     

基于历史数据聚类分析的暂态功角稳定故障筛选

大电网中有上千个暂态稳定故障,若对每个故障分别进行暂态评估,难以满足在线评估对时间的要求。为了满足电网在线暂态安全稳定评估快速性的要求,提出了一种基于电网运行历史数据聚类分析的暂态功角稳定故障筛选方法。基于历史数据中的电网运行方式和暂态功角稳定评估结果,提取关键特征量,通过计及稳定模式的矢量量化方法确定聚类数和初始聚类中心,采用K中心点算法对聚类中心进行优化。针对分类后暂态功角稳定的考察故障快速估算其暂态功角裕度,最后得到包含暂态功角失稳和估算裕度低于门槛值的故障组成的用于暂态稳定分析计算的严重故障集。通过对实际省级电网运行历史数据的聚类分析,验证了所述方法的有效性和实用性。     

暂态稳定断面功率极限区间和关联度指标计算

针对日益复杂的运行情况和系统对安全经济运行的要求,提出了暂态稳定断面功率极限区间和关联度指标计算方法。基于暂态安全稳定量化分析方法获得的预想故障下安全稳定裕度、模式和元件的参与因子,结合功率对输电断面功率的灵敏度计算发电机和负荷对断面功率极限的影响因子,通过发电机、负荷功率调整计算出功率极限的最大值和最小值。基于安全稳定裕度筛选得到输电断面关键故障,采用裕度为权重的加权平均计算发电机和监视母线的综合参与因子,通过发电机和母线参与因子的相关性分析计算两个输电断面的关联度指标。所提出的方法能够为调度运行人员快速掌握当前运行方式下各个输电断面的暂态安全稳定水平,以及彼此之间的交互影响程度提供技术手段,四川电网的算例分析验证了方法的实用性和有效性。     

在线多预想故障静态电压崩溃预防控制

提出在线多预想故障静态电压崩溃预防控制问题的数学模型及相应的数值计算方法。该模型以最小控制代价为目标,综合考虑了预防控制后正常运行点的可行性及多预想故障条件下的静态电压稳定裕度要求。对于多预想故障静态电压崩溃预防控制问题的求解,借鉴规划领域积极约束集策略的思想,在裕度扫描的基础上确定关键预想故障集,根据关键预想故障集计算预防控制策略,而后对预防控制后的电网进行裕度扫描,确定新的关键预想故障集,循环执行直至所有预想故障条件下的静态电压稳定裕度都得到满足。通过福建电网的数字仿真验证了模型的正确性及算法的有效性。     

N-2组合故障集的暂态功角稳定在线快速评估

大电网中N-2组合故障数目巨大,若对每个组合故障分别进行暂态功角稳定评估,难以满足在线评估的时间要求。基于N-2组合故障中第一个元件故障的暂态功角稳定在线评估结果(裕度和主导群发电机的参与因子),结合第一个元件故障的暂态功角稳定主导群中发电机的有功功率对第二个开断元件有功功率的灵敏度,计算出N-2组合故障的暂态功角稳定严重程度排序指标。通过优先对排序在前位的组合故障进行基于详细模型时域仿真的暂态功角稳定量化评估,直至排序号连续的多个组合故障的暂态功角稳定裕度都大于0,则直接判定排序在其后的所有组合故障均是暂态功角稳定的,从而满足N-2组合故障集暂态功角稳定在线评估对计算速度的要求。实际电网算例验证了该方法的有效性。     

基于支持向量机的在线暂态稳定故障筛选

为了满足在线暂态稳定评估计算时效性要求,基于历史大数据提出了一种采用支持向量机的暂态稳定预想故障筛选方法。结合扩展等面积准则暂态稳定量化评估方法,基于系统功角稳定模式和机组参与因子选择特征量,按照关键特征量将历史运行方式聚类,针对失稳样本分布分别采用分类和回归2种预测方法,在预测模型适用性判别和模型匹配基础上获得稳定裕度预测值、分类稳定预测结果和可信度量测,采用交互式并行计算进行在线暂态稳定故障筛选,可以在较大程度上避免SVM暂态稳定评估方法固有的误判情况。基于某实际电网的算例验证了所提方法有效性。     

大电网在线暂态稳定分析与控制系统研究综述

针对大电网在线暂态稳定分析与控制系统在计算速度和计算结果准确性方面的问题，介绍了大电网在线暂态稳定分析与控制系统的计算流程，从预想故障筛选、稳定评估、确定控制措施、工程应用等方面阐述了国内外的研究现状，并总结归纳了在线暂态稳定分析与控制领域的研究动态和发展趋势。     

台风天气条件下的电网暂态稳定风险评估

基于风险的分析方法可以定量地评估灾害条件下电网的短期安全稳定水平,并为电网的安全预警提供支持。提出了一种台风天气条件下的电网暂态稳定风险评估方法。该方法考虑了台风天气条件对输电线路运行可靠性的影响,并根据故障概率建立电网风险评估的预想故障集。对于预想故障集中不满足暂态稳定或静态安全的故障,建立了该故障下的最优紧急控制模型,并以紧急控制代价来衡量各预想故障的后果。最后通过新英格兰测试系统初步验证了所提出方法的有效性。     

考虑暂态稳定约束的最大输电能力计算

基于最优潮流技术和稳定性量化分析理论的扩展等面积准则(EEAC),提出了在预想故障集下求解互联电力系统暂态稳定约束下的最大输电能力计算方法。基于最优潮流技术建立了最大输电能力的数学模型,采用EEAC量化分析算法获取预想故障集的暂态稳定裕度,针对不安全的预想故障,采用基于安全稳定模式的预防控制技术将非线性的暂态稳定约束转化成临界群机组出力的线性约束,并最终通过内点算法求解。广东电网仿真算例验证了算法的有效性和实用性。     

电力系统预想故障分析GPU并行和图并行计算的比较研究

为保障电力系统安全运行,考虑预想故障的静态安全分析在调度运行中被广泛采用.随着系统规模不断扩大和预想故障集的不断增加,对在线实时预想故障分析的要求越来越高,高性能计算是实现在线实时预想故障分析的关键.图形处理器(graphics processing unit,GPU)和图计算高效的并行特性为实现大规模电网实时预想故障...     

基于统计学习的模糊暂态稳定事故筛选与排序

暂态稳定事故筛选与排序的目的是针对一组预想事故集合挑选出严重事故或滤除掉无害事故,以减少待分析的预想事故数目,满足在线动态安全分析的需要.文中提出一种基于统计学习的模糊暂态稳定事故筛选与排序方法,该方法采用了反映事故严重程度的10个性能指标,并通过样本学习,在每个指标集合上具体定义了系统稳定性的模糊隶属度函数;然后综合运用这10个性能指标的稳定性模糊隶属度得到的平均稳定性模糊隶属度,对预想事故集合按严重性进行了排序;接着根据排序结果,结合所设定的稳定阈值,将无害事故过滤掉.最后,用新英格兰10机39节点网络验证了该方法的有效性.     

An Improved On-line Contingency Screening for Power System Transient Stability Assessment

This paper presents a contingency screening method and a framework for its on-line implementation. The proposed method carries out contingency screening and on-line stability assessment with respect to first-swing transient stability. For that purpose, it utilizes the single machine equivalent method and aims at improving the prior developed contingency screening approaches. In order to determine vulnerability of the system with respect to a particular contingency, only one time-domain simulation needs to be performed. An early stop criteria is proposed so that in a majority of the cases the simulation can be terminated after a few hundred milliseconds of simulated system response. The method’s outcome is an assessment of the system’s stability and a classification of each considered contingency. The contingencies are categorized by exploiting parameters of an equivalent one machine infinite bus system. A novel island detection approach, appropriate for an on-line application since it utilizes efficient algorithms from graph theory and enables stability assessment of individual islands, is also introduced. The New England and New York system as well as the large-scale model of the Continental-European interconnected system are used to test the proposed method with respect to assessment accuracy and computation time.     

在线电压安全评估在北京电网中的应用

北京电网是京津唐(北京-天津-唐山)电网的枢纽,而且从区外受电比例过高,因而在线监测和分析北京电网的电压稳定问题显得尤其迫切.文中应用DSA PowerTools软件建立了在线电压安全评估系统对北京电网进行在线电压安全评估.它具有电压安全评估、故障筛选、确定预防控制措施、离线分析等电压安全评估功能,在此基础上开发了一个面向北京电网的数据接口程序和系统计算结果的Web浏览功能.北京电网的实际投运情况表明,整个系统的运行情况良好,实现了全部电压安全评估功能,还可通过数据接口程序实现用户交互故障设置和输入数据文件编辑等功能,并可利用Web更快速、直观地浏览计算分析结果.     

Power system probabilistic security assessment using Bayes classifier

This paper presents a method for power system security assessment based on the Bayes classifier. This method can be applied to calculate probabilistic security indices as well as on-line security assessment. In general, the determination of security breach is a cumbersome and time-consuming process due to dynamic and steady-state effects. These effects can be incorporated by considering transient stability, satisfaction of system load without violation of constraints, and voltage stability studies. The variation of the system load, as well as contingencies, may cause system transition to a different operating state. It is impractical if not impossible to evaluate all these situations, such as contingencies resulting from load variation. The straightforward Monte Carlo simulation, one of the possible methods in power system reliability analysis, requires the evaluation of a system operating state for each sampled state and is computation-intensive. In the proposed method, first the joint probability density of feature vectors has been obtained by using some training data. Once this joint distribution is obtained, the Bayes classifier provides the assessment of system security without complicated contingency analyses and can reduce the computational burden. Security status of a given feature vector can be determined by a posteriori probability rule called Bayes rule, which can be implemented in on-line security assessment or power system reliability studies.     

A composite electromechanical distance approach to transientstability

To offset the heavy computations involved in power system transient stability studies, the authors decompose the system into internal and external areas and reduce the latter. The identification of these areas relies upon a composite electromechanical distance, designed to assess propagation of transient phenomena relating to a given contingency. To encompass a set of contingencies, a combined composite distance is devised on the basis of the concept of correlation between composite distances. Also, to encompass a set of operating conditions, a similar technique is proposed. A composite distance handling both sets of contingencies and of operating conditions is developed. Overall, the approach attempts to comply with any method of transient stability assessment and to provide a tool for online applications. This network deals with its fundamentals. Essential features such as flexibility, efficiency and reliability are tested and illustrated by means of numerous simulations performed on a 31-machine system     

模糊子集和Taylor级数相结合的快速事故筛选方法

为避免在暂态稳定分析中稳定与不稳定状态的漏报,文中结合模糊子集理论和高阶Taylor级数,提出了一种用于在线暂态安全分析的快速事故筛选方法。该方法首先定义了7种 反映事故严重程度的性能指标,并把它们作为模糊隶属函数的组合特征输入量,然后通过多 元 多变量的模糊隶属函数,产生一个能够指示相对稳定裕度的连续分布的暂态稳定指标。基于这个连续分布的稳定指标,可为运行人员提供3条带,即“绝对”稳定带（稳定指标大）、“绝 对 ”不稳定带（稳定指标小）、“模糊”带（稳定指标处于中间值,即稳定与不稳定边界地带 ）,有了这3条带,就可对预想事故进行快速的暂态稳定识别。计算仿真结果表明了该方法 的快速性、可靠性和有效性。     

暂态稳定混合控制的优化:（二）不同失稳模式的故障集

改善某个失稳模式(UM)故障稳定性的预防控制可能损害其他UM故障的稳定性，因此在研究单一UM故障约束的混合控制优化的基础上，必须妥善协调不同UM故障约束的混合控制。文中通过在出力成本中引入紧急控制代价的途径，将该协调问题转换为不同出力成本机群间的经济调度问题。各UM之间的拓扑关系可能非常复杂，但“解耦迭代(局部优化)，聚合协调(全局优化)”的思路却相同，因此，构造了不同UM的故障约束下混合控制的协调模型及其寻优算法，通过算例验证了该算法的有效性。     

A unified approach to transient stability contingency filtering,ranking and assessment

This paper proposes a unified approach to contingency filtering, ranking and assessment in power system transient stability studies. The approach consists of two-block techniques in which the first block selects from a list of contingencies the a priori “interesting” ones, that the second block ranks and assesses. This filtering, ranking and assessment (FILTRA) approach relies on SIME (for Single Machine Equivalent). SIME is a hybrid direct-time-domain stability method which combines accuracy and flexibility skills of time-domain methods with sound additional possibilities of direct methods. The FILTRA approach is fully general: it may adapt itself to the specifics of any power system (modeling, protection characteristics, etc.), any contingency scenario and mode of (in)stability (first- or multi-swing, local or inter-area mode) and any application context (planning, operation planning and real-time operation). The approach is illustrated on two EHV power systems, having different structures, control and protective devices. The adequacy of its filtering and ranking capabilities is illustrated in terms of performance criteria such as reliability (ability to consistently capture all dangerous contingencies), effectiveness (ability to avoid false alarms) and computational efficiency (ability to comply with real-time requirements). Further, the assessment task is shown to provide the operator with sound information and effective means of control     

基于最优乘子潮流估计的故障筛选与排序

提出了一种用于电压稳定安全评估的快速故障筛选和排序方法。该方法从故障前的临界点出发,通过最优乘子潮流法计算得到的故障后边界点来估计故障后临界点,当初始点接近临界点,通过一次迭代即可满足所需的计算精度,从而快速地识别出非严重故障。对于严重故障和某些特殊情况的故障进行了分析并提出了解决办法,保证了对严重故障的估计精度。通过某一实际703节点系统算例验证了该方法的有效性。