随机生产模拟及其应用

随机生产模拟是研究现代电力系统运营的一个重要工具，能够提供系统在最优运行方式下生产成本的期望值以及可靠性指标。文中在对随机生产模拟方法进行简单综述的基础上，重点介绍了等效电量函数法的原理与计算流程，并阐述了有能量限制的发电厂的模型和算法。在随机生产模拟的应用方面，主要讨论了与电力系统可靠性评估密切相关的问题，以及电力市场环境下的电价预测与风险预报等问题。     

Comparison of probabilistic production cost simulation methods

The authors present the results of an investigation of the relative computational speeds and solution qualities of six different probabilistic production cost simulation methods for power systems. The six methods are: the piecewise linear approximation (PLA), segmentation, equivalent energy function (EEF), cumulant, mixture of normal approximation (MONA), and fast Fourier transform (FFT) methods. For energy calculations, considering both speed and accuracy, it is concluded that if accuracy is paramount then the EEF method with the MW interval chosen to be the maximum common divisor of the block capacities is preferred. If speed is paramount, then either MONA or cumulants is preferred     

基于等效电量函数法的互联电力系统随机生产模拟

本文把等效电量函数法推广到互联电力系统的随机生产模拟中，严格地处理了发电机组支援容量和联络线输送容量的随机性质，更精确地反映了互联系统之间的电能交换过程。数字算例表明，该方法具有很高的精确度和较高的模拟速度。     

基于拉格朗日插值法的概率建模方法及其在概率潮流分析中的应用

大规模可再生能源并网给电力系统带来大量概率不确定源,这会极大地增加电力系统概率潮流分析中对不确定源概率建模的计算负担。Nataf变换能够有效完成对皮尔森相关随机变量的概率建模,其关键在于标准正态分布域的相关系数求解。然而传统的基于辛普森数值积分法和二分法的相关系数求解法,使Nataf变换的过程耗时严重,难以达到实时计算的要求。为此,采用拉格朗日插值法和简化牛顿法实现相关系数的高效计算,以加快概率建模的过程,提高概率潮流分析的效率。基于改进的IEEE 118节点算例,测试了所提相关系数求解法的计算精度与速度,并进一步测试了其误差对整个概率潮流计算结果精度的影响。结果表明,所提方法能够高效而精确地完成Nataf变换中标准正态分布域相关系数的求解,从而在保证概率潮流结果精度前提下,提高概率潮流分析的效率。     

An efficient algorithm for optimal reservoir utilization inprobabilistic production costing

An efficient and accurate algorithm is presented which determines optimal storage reservoir utilization (pumped hydro) in probabilistic production cost models with multiple storage, thermal, and limited-energy units. The algorithm exploits the special nature of the production cost function, which is piecewise linear with respect to the reservoir utilization levels. It achieves the same accuracy as previously developed, less efficient, approaches which require multiple production cost calculations. The proposed algorithm is also more efficient as well as more accurate than heuristic reservoir utilization algorithms, which are prone to inaccuracies when multiple storage units are considered     

电动汽车充电站的概率负荷建模

电动汽车充电站负荷的随机性特征,使相关建立具有通用性负荷模型的研究存在一定的困难,针对三类典型电动汽车充电站,即电池更换站、居民区充电站、公共场所充电站,提出了一种以充电方式、地理位置、出行特征为基础的概率负荷建模方法,通过全面研究充电站负荷建模的影响因素,采用蒙特卡洛模拟与概率统计分析规律相结合的方法综合建立三类典型充电站的概率负荷模型。在此基础上,运用粒子群算法优化得到了填谷效应最优的三类典型充电站的优化配置方案,验证了所建立的概率负荷模型的有效性和实用性。     

Reliability Assessment of Micromachined Fixed–Fixed Beam Based on FE Simulation and Probabilistic Sampling

Recent trends in structural mechanics applications of finite-element methods (FEM) show an increasing demand for efficient analysis tools. This paper presents a realistic approach for modeling a fixed–fixed beam structure used in microelectromechanical systems based on finite-element analysis (FEA). The use of probabilistic methods to assess the electromechanical behavior of the beam under the presence of micromachine manufacturing and process uncertainties is also presented. The finite-element model of the beam is constructed using the commercial code ANSYS (10.0). In the standard approach of modeling, existing literature assumes deterministic values for design parameters. However, fabrication of the device introduces some amount of variation in these parameters. In this paper, the probabilistic approach is discussed to account for the variability in fabrication. FEA guides the design of fixed–fixed beam to achieve a robust and reliable design in a most efficient way. From the probabilistic analysis, it was observed that the changes in length and thickness tend to be the most influencing parameters, which need to be tightly controlled.      

发电系统中多蓄能电站的建模

针对电力系统中蓄能电站数目不断增多的情况 ,在单个抽水蓄能电站建模的基础上 ,建立了发电系统中多蓄能电站的随机生产模拟模型。该模型考虑了各蓄能电站的个体特征 ,因而与通常的将多个蓄能电站合并为一个蓄能电站的方法相比 ,文中提出的新模型有利于更细致地模拟系统运行状况 ,程序可确定各蓄能电站的最优发电量和发电位置 ,从而能够更精确地评估电力系统的可靠性和经济性。通过算例验证了模型的有效性。利用该算法开发的软件可用于包含多个蓄能电站的实际电力系统的效益评估 ,亦可用于多蓄能电站的优化运行调度     

基于反卷积波束形成算法的干式变压器异响故障识别技术

针对常规波束形成算法定位精度不高的问题,将基于反卷积变换的波束形成算法应用于干式变压器异响故障识别,分析了反卷积变换的波束形成算法基本原理及其用于干式变压器异响故障识别的可行性;研究了一种采用异响精准定位联合声纹图谱特征识别的干式变压器异响故障识别方法;提出了"高频特征峰能量比"的概念,用于量化机械异响严重程度;最后通...     

考虑综合能源站用电需求不确定性的配电网变电站机会约束规划

在能源互联网的发展背景下，综合能源站成为了高效清洁的终端用能载体。针对综合能源站用电需求的不确定性，提出了一种基于机会约束规划的配电网变电站规划方法。首先，基于综合能源站的各组成部分，分析了综合能源站作为能源配置中心在配电网中的多能互补特性和用电需求的不确定性；其次，构建了考虑综合能源站用电需求概率分布的配电网变电站机会约束规划模型，并给出了变电站规划中机会约束的检验方法；然后，采用层次性改进的加权Voronoi图算法对变电站规划模型进行求解；最后，通过算例分析验证了所提方法的实用性。     

Probabilistic transient stability assessment for on-line applications

The increasing need to improve security monitoring of networks by system operators is the main motivation of the work described in this paper. The paper provides an algorithm for the on-line probabilistic transient stability assessment of existing or forecasted operating conditions. The proposed algorithm is an analytical method making use of two types of information: (i) transient stability assessment tool, and (ii) probabilistic factors. The corrected transient energy margin (CTEM), which is a hybrid method, is used to on-line transient stability assessment. The probabilistic factors of the conditional probability theorem were included in our method. Hence, our algorithm calculates the probability of the transient instability through using the CTEM and probabilistic factors in the transient stability in an on-line manner for exciting or forecasted operation condition for short term operation condition (e.g., next 1 h period). The implementation of the proposed method to New England 39-bus test system showed the ability and good performance of the method for the probabilistic assessment of the transient stability. Also, the method provides the system operator with a profound insight into the system stability conditions. The results retrieved again with changed operation conditions; therefore, the system operator can sometimes improve the system stability condition through making little changes in the power output of generators.     

基于风场景识别的动态风电功率概率预测方法

传统风电功率预测是确定的、静态的、非条件性的,无法代表不同外部状态的发电过程,缺失预测误差的概率性信息。针对上述问题,提出了一种动态的基于风场景识别的风电功率概率预测方法。首先建立基于K means的风场景识别模型,根据风速和风向识别自然风特征,据此划分风电场风况类别。然后针对各风况类别建立基于相关向量机的概率预测模型。在实际预测中,根据实时风况动态调整概率预测模型参数。以中国西北某风电场为例进行验证,结果表明,该方法提高了单点预测精度、概率预测可靠性和技术分数、运行效率,为预测细化建模提供新的解决思路。     

基于古诺博弈的容量补偿与容量持留比较

首先利用电力系统随机生产模拟技术,从理论上阐明了英国早期电力市场和当量电价的容量补偿基本原理。基于成本的分析表明,英国式的容量补偿主要考虑了机组强迫停运所引起的可靠性的容量价值补偿,而这一部分价值没有体现在能量市场规则中,所以补偿是必须的;当量电价除了补偿这部分价值外还包括了规模经济性依然存在所需要的补偿。然后构造了发电厂商采用容量持留策略的智能代理仿真模型,其中包括了能量主市场和备用辅助服务市场,进一步检验并比较了在寡头市场条件下这2种都具有容量补偿功能的市场运行特点。结果表明,在当量电价机制下,发电厂商没有实施容量持留行为的策略空间,并能引导出既自愿又充足的申报容量,且能维持市场电价的稳定。而在英国早期的电力市场中,发电厂商可以利用持留容量获得超额利润,同时造成申报容量的不足和市场电价的飞升,而且越是备用容量不足,发电厂商的这种市场力就越大。而造成这种结果的真正原因是统一出清电价本身,容量补偿方法对于激励或抑制发电商市场力的作用都相当有限。因此,在通常的寡头竞争市场,基于统一出清的英国容量补偿方法不具有市场的有效性和稳健性,而当量电价方法既能给予充分的容量回报,又具有良好的市场有效性和稳健性。     

PSO 优化的最大峭度熵反褶积齿轮箱故障诊断

考虑到最小熵反褶积只对单一的异常振动信号很敏感,而且,滤波器的长度需要人工调控,提出了一种最大峭度熵反褶积方法,并将其应用于轴承故障诊断。考虑峭度熵具有突出连续冲击振荡的优点,选择峭度熵作为反褶积的目标函数。同时,利用峭度熵作为改进的局部粒子群优化算法的适应度函数,利用局部粒子群优化滤波器长度,使最大峭度熵反褶积在解卷积时自适应地调整滤波器长度,从而能够准确地提取出连续的脉冲信号。实验分析结果验证了该方法能够更加有效的提取连续脉冲信号的能力,提升了故障诊断的精度。     

负荷建模的多目标优化

改进了传统负荷参数辨识的目标函数,将现有负荷模型参数辨识的单目标优化问题转化成多目标优化问题,并在改进强度Pareto进化算法的基础上引入并行遗传算法的思想,进行多目标参数辨识,力求克服目前困扰负荷建模及其参数辨识中收敛速度慢、易发散等问题。解决了以前算法只能辨识出一组参数的问题,便于决策者根据不同侧重进行参数选取。高效、高精度的并行算法为网格平台下的负荷建模做了前期准备。最后,对上海地区的负荷进行实测建模,结果表明所述建模策略的可行性。     

Statistical distribution for wind power forecast error and its application to determine optimal size of energy storage system

Accurate wind power forecast is an important tool for wind farm to participate in day-ahead or hours-ahead energy markets. However, forecast errors with any methodology are so large that they cannot be neglected. The forecast error needs to be analyzed individually for single wind farm to estimate the impact of this error on trading wind energy in electricity market. Although forecast error is always assumed as normal distribution, it can be demonstrated that it is not proper with a simple statistical analysis. In this paper, a mixed distribution is proposed based on laplace and normal distribution to model forecast errors associated with persistence forecast for single wind farm over multiple timescales. Then the proposed distribution is used to estimate the penalties for prediction errors in the electricity market. Energy storage system (ESS) can smooth the wind power output and make wind power more “dispatchable”. A probabilistic method is proposed to determine optimal size of ESS for wind farm in electricity markets. The results indicate that the proposed distribution and probabilistic method is efficient to find optimal size of ESS.     

考虑输出功率相关性的光伏电站典型场景生成方法研究

含光伏的传统概率潮流计算常使用Beta、Weibull等分布模型,但这些模型难以精确体现不同场景下输出功率特性的变化。针对此问题,文中提出一种光伏输出功率多场景生成方法。该方法将多个光伏电站输出功率的相关性以及相关性跟随外界条件的变化纳入考量范围,可实现多个光伏电站输出功率的精确建模。首先,对光伏电站历史输出功率数据进行基于密度中心的聚类处理,产生的多个聚类中心作为输出功率场景;其次,对不同场景进行核密度估计,建立Copula函数以描述多个输出功率的概率分布;然后,对生成的多场景概率分布模型进行拉丁超立方采样,利用生成的样本进行概率潮流计算,评估含光伏的配电网运行状态;最后,分析算法的稳定性,讨论采样规模对计算结果的影响。结果表明,文中提出的多场景生成方法有助于提升光伏输出功率的建模精度和概率潮流计算精度。     

Fixed‐order optimal deconvolution filter with irregular missing data

In general, the reconstruction performance of the conventional deconvolution filter is deteriorated by the missing data. In this paper, a fixed‐order deconvolution filter design method is proposed for the signal reconstruction from received signal with irregular missing data. The missing data model is based on a probabilistic structure. The probability of occurrence of missing data is unknown a prior. In this situation, the deconvolution filter design problem becomes a complicated nonlinear estimation problem. In this study, a design method based on genetic algorithms is proposed to treat the signal reconstruction design problem with irregular missing data. Finally, two examples are given to illustrate the simulation results of the proposed deconvolution filter. The results show that the reconstruction performance is improved significantly if the missing probability is considered in the deconvolution filter design procedure. Copyright © 2009 John Wiley & Sons, Ltd.     

改进的概率稳定评估方法及其应用

针对概率稳定评估方法中存在的计算复杂性问题，提出了基于改进故障枚举法的分区概率稳定评估模型。并将其应用于总元件数达324个的实际大规模发输电组合系统的可靠性评估中，采用该模型后的计算量仅占常规故障枚举法的0．483％，从而使概率稳定分析达到实用化水平。依据该文提出的算法和计算步骤所得到的概率稳定指标能定量反映系统的安全水平，算例计算表明该方法正确有效，计算结果合理并具有实际参考价值。     

基于SOCP的综合能源系统日前调度概率最优能量流

随着能源危机的加重,再电气化成为破解能源发展难题的必然选择。根据电气互联综合能源系统作为再电气化的一种新思路,提出利用二阶锥规划求解综合能源系统日前优化调度概率最优能量流的方法。首先,利用电力系统、天然气系统和能源集线器构建综合能源系统日前调度概率模型;然后,将综合能源系统日前调度概率模型放缩为凸模型;接着,采用点估计法求解综合能源系统日前调度概率最优能量流;最后,利用典型算例在MATLAB上的YALMIP平台验证此算法的正确性与有效性。