基于谐波限值的分布式电源准入功率研究

针对分布式电源接入配电网后会对电网电能质量产生不利影响的问题,对分布式电源的接入容量及位置进行了研究。在以配电电能质量符合国家标准的前提下,采用一种结合人工蜂群算法的分布式电源准入功率最大化配置方法对分布式电源准入功率进行了计算。针对多种分布式电源接入配电网的情况,首先分析了不同接入位置和不同容量的分布式电源对电网的影响;然后考虑了分布式电源对配电网电压偏差和谐波的影响;最后利用算例对优化配置方法的可行性进行了测试,确定了分布式电源接入配电网的优化配置方案。研究结果表明,该优化方案能够达到优化目标,满足电压调整和谐波畸变限制的约束条件,最大化地提高分布式电源准入功率,同时为分布式电源最佳接入点提供参考。     

主动配电网储能优化规划

大量分布式电源的接入使得主动配电网成为现有配电网的发展趋势及方向,可再生能源发电的间歇性将会提高配电网的风险,解决这些问题最有效的方法就是配置适当的储能装置,合理地优化配置储能装置不仅能提升主动配电网对分布式能源的消纳能力还能提高主动配电网运行的稳定性。主动配电网储能长期优化规划以短期优化为基础,短期优化考虑了储能系统的削峰填谷及调节馈线节点电压水平的能力从而决定储能的额定功率,长期优化规划模型以主动配电网经济运行成本最小为目标函数考虑储能投资成本以及主动配电网的运行成本及可靠性成本,通过禁忌搜索-粒子群混合算法求解得到电池储能装置的最优位置、容量及额定功率,算例验证了所提模型及其求解方法的可行性。     

基于GPRS的配电网动态无功优化控制策略研究

配电网无功优化控制是解决配电网电能损耗大、电压水平低这一问题的有效手段,采用动态无功优化求解时一般按照各节点全天短期预测负荷曲线合理分段优化,即将动态无功优化控制转化为多时段静态无功优化问题.针对现有配电网实际负荷的不规则变化会给该优化方法带来无功过补偿和欠补偿的问题,提出了一种基于实测负荷数据和预测负荷数据的动态无功优化混合控制策略;为了提高配电网无功优化的计算速度,使优化算法更好地适用于实际在线环境,引入了序优化理论框架,采用了改进的禁忌搜索算法作为无功优化算法;通过对34节点配电系统进行了算例分析.研究结果表明,该控制策略和优化算法在实用性、可行性和计算速度等方面均有良好表现.     

农村配电网无功优化新模式探讨

针对农村供电现状,提出了基于以电网实时监测为基础,以用电管理为核心的变电站、线路、配变电压三级联调的无功优化新模式,加强配电网电能质量的管理,以提高电压质量、降低运行线损,为农村"低电压"综合治理提出了整体解决方案。     

基于蓄电池储能的主动配电网优化配置模型研究

主动配电网中分布式能源的合理配置是电网系统得以经济、可靠运行的重要因素。现建立了日前多时段优化模型,考虑了微型燃气轮机、光伏发电、风力发电等间歇性分布式发电及蓄电池储能在主动配电网中有功—无功功率的出力特性。由于优化配置模型涉及非线性潮流模型以及蓄电池状态切换的整数变量,所以难以快速准确地求解该优化配置问题。据此采用二阶锥优化算法松弛原模型,调和求解精度和计算速度的矛盾。在修改的西门子Benchmark低压配电网中验证了所提模型,结果表明,所提模型准确度高,适应性好,符合工程实际应用需求,二阶锥优化算法能有效快速地求解问题。     

浅析配电网的安全经济运行

详细分析了县级配电网能量损耗的因素,提出了通过合理调整电网运行电压,加强无功管理,提高电网功率因数,合理确定配电网的各级电压水平,保证变压器的经济运行等措施,达到降低配电网中能量损耗的目的,从而实现配电网的安全经济运行。     

面向对象的配电网无功补偿配置优化算法研究

提出一种针对配电网无功优化的面向对象建模方法,能更准确逼真地刻画配电网无功补偿问题。同时由于优化模型的目标函数、约束条件等各组成部分均以对象形式表示,使得对优化问题的描述具有更好的可扩展性,因此也更容易适应新形势下不断变化的电力系统无功优化问题。此算法在JAVA环境下基于开源遗传算法函数库——Jenetics得以实现,以实际配电网的算例验证了本文所提方法的正确性和有效性。     

针对冲击性负荷接入配电网的无功配置方法

冲击性负荷在生产或运行过程中会周期性或非周期性地从电网中取用快速变动功率,接入配电网后往往对电压质量及线损产生不利的影响,以三相交流电弧炉为例分析了冲击性负荷接入对配电网电压的影响机理,并综合考虑电压质量、线损以及投资的约束,提出了一种可用于冲击性负荷接入配电网的动静态混合无功优化配置方法。经算例验证表明,采用所提配置方法效果良好,对工程应用具有一定指导价值。     

基于柔性分析的智能配电网运行方式优化方法

随着智能电网的逐步发展,需要对配电网的运行方式进行更为全面合理的优化。目前的配电网运行方式优化方法通常以经济性为目标,来寻求满足一定的安全可靠性约束的运行方式。这种方法实际上将配电网运行的安全性、可靠性和经济性割裂开来,存在着一定的片面性和局限性。现将智能电网中的柔性分析方法引入到配电网运行方式优化中,提出了对配电网运行的柔性程度进行评价的指标,将传统配电网运行优化模型的目标函数和约束条件进行了柔性化处理,建立了基于柔性分析的配电网运行方式柔性综合优化模型,从而使所求得的运行方式达到了安全性、可靠性和经济性等多方面的综合最优。     

基于改进粒子群算法的主动配电网有功无功协调优化控制

针对主动配电网有功无功协调优化控制过程中受到网络环境的影响,导致主动配电网的运行稳定性下降,为此提出了基于改进粒子群算法的主动配电网有功无功协调优化控制。根据主动配电网接入系统的连接原理,以电压稳定性和运行经济性为优化目标,表征了配电网运行状态并计算出电力系统的网损,将系统的潮流方程、无功补偿容量和状态变量作为约束条件,构建了主动配电网有功无功协调模型,利用改进粒子群算法的寻优策略,对配电网有功无功之间的平衡点进行了线性化处理,通过建立时滞微分方程,消除了网络环境对主动配电网有功无功协调优化控制过程的影响,结合射影反馈控制系统,实现了主动配电网有功无功的协调优化控制。实验结果表明,基于改进粒子群算法的协调优化控制方法在控制误差方面具有很好的性能,还可以提高协调优化控制的效率。     

Minimal Realization of Linear Graph Models for Multi-physics Systems

An engineering system may consist of several different types of components,belonging to such physical"domains"as mechanical,electrical,fluid,and thermal.It is t...     

INTEGRAL EQUATION METHOD＇S APPLICATION IN HOLE-EDGE STRESS OF COMPOSITE MATERIAL PLATE WITH DIFFERENT SHAPED HOLES

The strength of composite plate with different hole-shapes is always one of the most important but complicated issues in the application of the composite material. The holes will lead to mutations and discontinuity to the structure. So the hole-edge stress concentration is always a serious phenomenon. And the phenomenon makes the structure strength decrease very quickly to form dangerous weak points. Most partial damage begins from these weak points. According to the complex variable functions theory, the accurate boundary condition of composite plate with different hole-shapes is founded by conformal mapping method to settle the boundary condition problem of complex hole-shapes. Composite plate with commonly hole-shapes in engineering is studied by several complex variable stress fimction. The boundary integral equations are founded based on exact boundary conditions. Then the exact hole-edge stress analytic solution of composite plate with rectangle holes and wing manholes is resolved. Both of offset axis loadings and its influences on the stress concentration coefficient of the hole-edge are discussed. And comparisons of different loads along various offset axis on the hole-edge stress distribution of orthotropic plate with rectangle hole or wing manhole are made. It can be concluded that hole-edge with continuous variable curvatures might help to decrease the stress concentration coefficient; and smaller angle of outer load and fiber can decrease the stress peak value.     

Non-monotonic material contrast in scanning ion and scanning electron images

30 keV Ga⁺ focused ion beam induced secondary electron (iSE) imaging was used to determine the relative contrast between several materials. The iSE signal compared from C, Si, Al, Ti, Cr, Ni, Cu, Mo, Ag, and W metal layers does not decrease with an increase in target atomic number Z₂, and shows a non-monotonic relationship between contrast and Z₂. The non-monotonic relationship is attributed to periodic fluctuations of the stopping power and sputter yield inherent to the ion–solid interactions. In addition, material contrast from electron-induced secondary electron (eSE) and backscattered electron (BSE) images using scanning electron microscopy (SEM) also shows non-monotonic contrast as a function of Z₂, following the periodic behavior of the stopping power for electron–solid interactions. A comparison of the iSE and eSE results shows similar relative contrast between the metal layers, and not complementary contrast as conventionally understood. These similarities in the contrast behavior can be attributed to similarities in the periodic and non-monotonic function defined by incident particle–solid interaction theory.     

Application of Feature Extraction through Convolution Neural Networks and SVM Classifier for Robust Grading of Apples

This paper proposes a novel grading method of apples,in an automated grading device that uses convolutional neural networks to extract the size,color,texture,an...     

分布动态载荷识别的抗噪处理

针对正交多项式频域法在用多种响应对矩形薄板进行载荷识别中抗噪性较差的问题,综合运用平均法、矩阵预处理和奇异值截断法等方法对之进行改善,并引入空间映射的思想,将该方法的应用范围拓展为复杂的模型.利用仿真算例,证实了该方法具有较好的抗噪性.     

基于MELTAC-N平台的核电厂安全级DCS环网研究与测试

针对工程实践中环网通讯相关问题的处理缺乏理论基础及国产化安全级DCS平台的开发缺乏成熟经验借鉴问题,对基于MELTAC-N平台核电厂安全级DCS环网的软硬件实现进行了研究。提出了安全级DCS环网双环网冗余设计、光切换开关设计等硬件设计方法,以及以RPR协议为基础,采用全数据收发策略的软件设计方法。在CPR1000安全级DCS平台上对安全级DCS环网的可靠性及实时性进行了评价,并进行了容错能力、响应时间及响应时间稳定性测试验证实验。结果表明,基于MELTAC-N平台安全级DCS环网软硬件设计具有较好的容错能力及响应时间稳定性。     

Short-Term Relay Quality Prediction Algorithm Based on Long and Short-Term Memory

The fraction defective of semi-finished products is predicted to optimize the process of relay production lines, by which production quality and productivity ar...     

End-to-End Multiview Gesture Recognition for Autonomous Car Parking System

The use of hand gestures can be the most intuitive human-machine interaction medium.The early approaches for hand gesture recognition used device-based methods....     

The laboratory simulation of abrasive wear

Abrasive wear has long been recognised as one of the most potentially serious tribological problems facing the operators of many types of plant and machinery; several industrial surveys have indicated that wear by abrasion can be responsible for more than 50% of unscheduled machine and plant stoppages. Locating the operating point of a tribological contact in an appropriate operational ‚map’︁ can provide a useful guide to the likely nature and origins of the surface degradation experienced in use, though care must be exercised in choosing the most suitable parameters for the axes of the plot. Laboratory testing of materials and simulations of machine contacts are carried out for a number of purposes; at one level for the very practical aims of ranking candidate materials or surface hardening treatments in order of their wear resistance, or in an attempt to predict wear lives under field conditions. More fundamentally, tests may be aimed at elucidating the essential physical mechanisms of surface damage and loss, with the longer term aim of building an analytical and predictive model of the wear process itself. In many cases, component surface damage is brought about by the ingress of hard, particulate matter into machine bearing or sealing clearances. These may be running dry although, more usually, a lubricant or service fluid is present at the interface. A number of standardised wear test geometries and procedures have been established for both two- and three-body wear situations, and these are briefly described. Although abrasive wear is often modelled as following an ‚Archard’︁ equation (i.e. a linear increase in material loss with both load and time, and an inverse dependence on specimen hardness) both industrial experience and laboratory tests of particularly lubricated contacts show that this is not always the case: increasing the hardness differential in an abrasively contaminated lubricated pair may not always reduce the rate of damage to the harder surface.     

ANGULAR DISTORTION ALLOWABLE VALUE AND ASSESS METHOD OF WELD ON COKE TOWER

A graph as the new engineering method for estimate the safety of bulging deformation of coke tower is proposed. Through stresses analysis of circumferential weld of coke tower and comparing the stresses produced by pressure with heat stress of steady state, residual stress, bending stress produced by both itself weight and wind loads, it showed that the stresses produced by pressure on the angle distortion are the main factor of equivalent stress of the combined stress. After comparing four kinds of stress controlling conditions, the relation to stress with depth of angular distortion, grade of curvature of angular distortion and half of region of angular distortion has been inferred. Graph of deformation allowable value of coke tower for different condition by angular distortion and half of region of angular distortion has been plotted. The five steps for its engineering use have been explained. The lighter the grade of curvature is, the larger of bulge allowance, may be, and the bigger of depth of angular distortion may pose too. For the coke tower with a popular structure of Dg 5 400 mm×28 mm, the result by graph is nearly more than the result of two formulas formed by other research, the error is less than 7.0%. But, the graph can be easily applied to different size of angular distortion.