共查询到18条相似文献,搜索用时 203 毫秒
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基于序贯仿真和非参数核密度估计的大电网可靠性评估 总被引:6,自引:3,他引:3
序贯蒙特卡罗仿真不但能给出可靠性指标的期望值估计,而且能提供逐年可靠性指标样本。文中研究了序贯蒙特卡罗仿真的收敛特性,分析了仿真年数与计算精度之间的概率不确定性关系,推导了二者的置信区间公式,为实现计算成本和计算精度的综合权衡提供了量化分析手段。此外,基于逐年可靠性指标样本和非参数核密度估计理论,实现了可靠性指标的概率密度估计,从根本上克服了传统期望值指标仅从概率平均意义角度测度系统可靠性的缺点,探索了从可靠性指标内在分布规律和结构特征出发,深刻揭示电网风险特性的新思路。 相似文献
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马振宇 《电力系统保护与控制》2009,37(14):55-58
研究了电网可靠性评估的蒙特卡洛仿真的基本原理,对其收敛特性进行了深入分析,探讨了计算精度和样本容量之间的概率不确定性关系,推导了计算精度和样本容量的置信区间公式,应用这些公式可实现计算精度和计算成本的综合权衡,通过对RBTS、IEEE-RTS 79、IEEE-RTS 96可靠性测试系统的计算分析,验证了所提方法的正确性和有效性。 相似文献
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电网可靠性的蒙特卡洛仿真研究 总被引:4,自引:0,他引:4
马振宇 《电力系统保护与控制》2009,37(14)
研究了电网可靠性评估的蒙特卡洛仿真的基本原理,对其收敛特性进行了深入分析,探讨了计算精度和样本容量之间的概率不确定性关系,推导了计算精度和样本容量的置信区间公式,应用这些公式可实现计算精度和计算成本的综合权衡,通过对RBTS、IEEE-RTS 79、IEEE-RTS 96可靠性测试系统的计算分析,验证了所提方法的正确性和有效性. 相似文献
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大电网概率风险评估为电网可靠性性能分析及其薄弱环节识别提供了量化分析的技术手段。详细介绍了序贯蒙特卡洛仿真的基本原理和可靠性指标概率密度分布估计理论,然后采用序贯蒙特卡洛仿真法对四川500 kV和220 kV电网的四种运行方式进行了可靠性评估计算。另外,基于核密度估计技术得到了可靠性指标的概率密度估计,探索了从可靠性指标内在分布规律和结构特征出发深刻揭示电网风险特性的新思路,实现了对四川电网风险更深入的认知。 相似文献
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随着电网的日益发展及电力负荷压力的不断增大,准确评估高压直流输电系统可靠性对电力系统安全稳定运行具有重大意义。本文将重要抽样法与序贯蒙特卡洛模拟法相结合,提出了一种应用于高压直流输电系统可靠性评估的序贯重要抽样法。该方法结合序贯蒙特卡洛模拟法与重要抽样法的优点,既充分利用了系统原始参数,得到系统真实运行的时序信息,又有效地降低了抽样方差,加快了收敛速度。应用该方法对典型单、双十二脉高压直流输电系统进行了可靠性评估,并与采用传统序贯蒙特卡洛模拟法、序贯交叉熵法的评估结果进行对比。结果表明:序贯重要抽样法在确保计算精度的基础上显著缩短了仿真时间,具有较高的计算效率。 相似文献
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大电网可靠性蒙特卡洛仿真的概率不确定性分析 总被引:8,自引:3,他引:5
系统状态随机抽样是大电网可靠性蒙特卡洛仿真的重要基础环节,抽取的样本容量与仿真结果的精度和仿真耗时密切相关,因此在给定仿真精度时实现样本容量的概率预估和在给定样本容量时实现计算精度的概率预测,是实现计算精度和计算成本综合权衡的关键。基于中心极限定理深入研究随机变量的样本均值与期望值之间误差的概率预测方法,在此基础上分析失负荷概率(loss of load probability,LOLP)指标的方差系数和样本容量之间的关系表达式,导出方差系数给定时的样本容量置信区间公式及样本容量给定时的方差系数置信区间公式。这些公式的导出,对于实现仿真精度和样本容量之间的定量概率分析具有重要意义,通过对RBTS和RTS96可靠性测试系统的评估分析验证所提方法的有效性和正确性,并得出相关结论。 相似文献
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由于电力系统的元件故障为小概率事件,在应用传统非序贯蒙特卡洛抽样法进行系统可靠性评估时,存在抽样次数大,仿真时间长等缺点。通过将对偶变数抽样法与交叉熵重要抽样法相结合,提出了一种适用于电力系统可靠性评估的改进抽样方法。该方法首先通过交叉熵重要抽样确定元件最优参数,构造元件的零方差概率密度函数的近似函数,然后根据最优参数进行对偶抽样,进一步降低抽样过程的方差,提高了传统蒙特卡洛法的抽样效率。应用该方法及传统随机抽样法、对偶变数抽样法和交叉熵重要抽样法对IEEE-RTS(可靠性校验系统)与变参数后的IEEE-RTS进行可靠性评估,计算结果表明:提出的方法在保证一定计算精度的条件下,相比其他方法,进一步提高了仿真速度。越是小概率事件,方法的优势越明显。 相似文献
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采用等分散抽样法的电力系统概率仿真 总被引:2,自引:1,他引:2
针对电力系统概率仿真中常规蒙特卡洛抽样容量太大、效率低的问题,采用等分散抽样技术减少抽样次数和计算时间,从而提高模拟精度,加快蒙特卡洛的收敛速度。由IEEE标准系统的计算结果表明该方法是可行有效的。 相似文献
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In order to further development of the microelectronic systems and to achieve the circuits with higher speed, higher density and lower power consumption, new technologies to replace the conventional CMOS technology must be introduced. Quantum-dot cellular automata (QCA) is an emerging nanotechnology that provides a new method for computation at the nanoscale regime. In this paper, two methods e.g. artificial neural network and a mathematical algorithm based on the QCA cell–cell response function named Tansig method are used for the modeling and simulation of QCA circuits at the cell level. The accuracy and performance of the proposed methods are analyzed through few circuits. The results of these two approaches are compared with each other and QCADesigner software. The results show the feasibility and acceptable accuracy of these types of simulations. Also, these methods enable the simulation of large QCA circuits at the cell level with acceptable precision in a short time with the ability to implement in other circuit simulators such as HSPICE and so on. 相似文献
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多阶段输电网络最优规划的并行蚁群算法 总被引:15,自引:3,他引:12
多阶段输电网络最优规划是一个复杂的非线性组合优化问题,难以采用传统的数学优化方法求解。蚁群算法是近年来出现的用于解决组合优化问题的一种高效的内启发式搜索技术,但存在着未成熟收敛问题。文中给出了多阶段输电网络最优规划的数学模型及其解的向量形式;详细分析了传统蚁群算法的未成熟收敛现象及其原因;提出一种并行蚁群算法并用于求解多阶段输电网络最优规划问题。并行蚁群算法无需初始可行解,能很好地协调局部搜索与全局搜索,在加快计算速度的同时有效地避免了因参数设置、种群规模等不同而引起的未成熟收敛。对实际算例的计算结果表明,该方法具有很高的计算效率和良好的全局收敛性。 相似文献
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Yijiang Shen Ngai Wong Edmund Y. Lam Cheng‐Kok Koh 《International Journal of Circuit Theory and Applications》2011,39(9):905-921
The importance of thermal effects on the reliability and performance of VLSI circuits has grown in recent years. The heat conduction problem is commonly described as a second‐order partial differential equation (PDE), and several numerical methods, including simple explicit, simple implicit and Crank–Nicolson methods, all having at most second‐order spatial accuracy, have been applied to solve the problem. This paper reviews these methods and further proposes a fourth‐order spatial‐accurate finite difference scheme to better approximate the PDE solution. Moreover, we devise a fourth‐order accurate approximation of the convection boundary condition, and apply it to the proposed finite difference scheme. We use a block cyclic reduction and a recently developed numerically stable algorithm for inversion of block‐tridiagonal and banded matrices to solve the PDE‐based system efficiently. Despite their higher computation complexity than direct computation in a sequential processor, we make it possible for the very first time to employ a divide‐and‐conquer algorithm, viable for parallel computation, in heat conduction analysis. Experimental results prove such possibility, suggesting that applying divide‐and‐conquer algorithms, higher‐order finite difference schemes can achieve better simulation accuracy with even faster speed and less memory requirement than conventional methods. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
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In this paper, two algorithms are proposed for the computation of the static generation reliability of a power system. The loss-of-load probability (LOLP), which is the reliability index usually employed in static generation reliability evaluation, is computed by using both the capacity outage table and effective load approaches. Numerical results obtained from the study of a sample power system consisting of 44 generating units are compared in terms of the required computational time and numerical accuracy. It is found that, with the generating capacities properly rounded off, the capacity outage table method can be employed as an effective means of computing power system reliability. The effect of generation expansion planning on generation reliability is also examined. 相似文献