摘要：近年来,风力发电和光伏等新能源发电技术的高速发展,其中风力发电技术相对成熟且风力发电的并网规模较大。...近年来,风力发电和光伏等新能源发电技术的高速发展,其中风力发电技术相对成熟且风力发电的并网规模较大。由于受到自然条件因素风速变化的影响,使得风电场出力具有随机波动特性,并且多风电场功率间存在相关性,因此有必要研究风电场接入电力系统对静态电压稳定裕度(static voltage stability margin,SVSM)水平产生的不确定性影响。本文基于连续潮流法和仿射区间算法,对考虑风电场出力不确定性及多风电场功率相关性下的电力系统SVSM计算进行研究。采用区间数来描述风电场出力的随机波动特性,基于连续潮流法和仿射区间算法,提出了含风电场的电力系统SVSM区间的计算方法。首先根据电压稳定极限点分岔类型的不同将风电场出力波动区间进行分段,然后采用连续潮流法分别求出每段区间中心值对应的SVSM,并根据相应分岔点类型计算出SVSM对风电场出力的一阶灵敏度,最后结合线性规划模型优化噪声元范围以获得区间收缩结果,从而得到SVSM区间。采用区间相关角表示不同风电场出力区间的相关性,根据分岔点类型相同与否,采用不同的处理方法计算得到SVSM区间。以IEEE-39节点系统和某964节点实际省级电网为例,验证了所提出方法计算得到的SVSM区间具有较高的精度,且计算量明显减小。针对高风电渗透率的电力系统,提出一种基于改进连续潮流法和考虑二次项的改进仿射区间算法的电力系统SVSM区间的计算方法。该方法直接先采用改进连续潮流法分别求出风电场出力区间中心值对应的SVSM及对应的分岔点类型,并根据分岔点类型计算出SVSM对风电场出力和非平衡节点发电机的一阶和二阶灵敏度,最后结合线性规划模型优化计算噪声元区间范围获得区间收缩结果,从而得到SVSM区间。所建立的改进连续潮流计算模型中负荷有功增长量和风电功率波动量是由除平衡节点发电机外的其他所有发电机来承担,而负荷有功增长和风电功率波动引起的网损变化量由平衡节点发电机承担。对于多风电场,通过直接对相关的风电场出力区间变量进行去相关处理后得到相互独立的区间变量,并基于改进连续潮流法和改进仿射区间算法计算得到SVSM区间。以IEEE-39节点系统和某964节点实际省级电网为例,验证了所提出方法计算得到的SVSM区间具有较高的精度,且计算量明显减小。更多还原显示全部
摘要：For some engineering design and manufacturing applications, particularly for evolving and newtechno...For some engineering design and manufacturing applications, particularly for evolving and newtechnologies, populations of manufactured components can be heterogeneous and consist ofseveral sub-populations. The co-existence of n subpopulations is particularly common in deviceswhen the manufacturing process is still maturing or highly variable. A new model is developedand demonstrated to simultaneously determine burn-in and age-based preventive replacementpolicies for populations composed of distinct subpopulations subject to stochastic degradation.Unlike traditional burn-in procedures that stress devices to failure, we present a decision rule thatuses burn-in threshold on cumulative deterioration, in addition to burn-in time, to eliminate weaksubpopulations. Only devices with post-burn-in deterioration levels below the burn-in thresholdare released for field operations.Inspection errors are considered when screening burned-indevices. Preventive replacement is employed to prevent failures from occuring during fieldoperation. We examine the effectiveness of such integrated burn-in and preventive replacementpolycies for non-homogeneous populations.Numerical examples are provided to illustrate theproposed procedure. Sensitivity analysis is performed to analyze the impacts of modelparameters on optimal policies. Numerical results indicate there are potential cost savings fromsimutaneouly determining burn-in and maintenance policies as opposed to a traditional approachthat makes decisions on burn-in and maintenance actions separately.显示全部
