基于一致性算法的电力系统分布式经济调度方法综述

传统集中式调度方法难以满足高渗透率分布式电能资源接入背景下电力系统经济调度的需求,分布式经济调度方案因具有可靠性高、可扩展性强、通信计算负载均匀等特点得到了越来越多的关注。对电力系统分布式经济调度方法的国内外研究现状进行了综述,重点阐述了一致性算法的原理、应用及成为分布式经济调度主导算法的原因。比较了集中式和分布式经济调度系统及问题的求解过程,分析了分布式经济调度实现过程的关键环节,并对现有关键问题解决方法的优缺点进行了评述,分析了电力系统分布式经济调度方法研究中有待解决的问题并提出了未来可进一步研究的方向。     

Parametric study of seismic performance of super-elastic shape memory alloy-reinforced bridge piers

One of the important measures of post-earthquake functionality of bridges after a major earthquake is residual displacement. In many recent major earthquakes, large residual displacements resulted in demolition of bridge piers due to the loss of functionality. Replacing the conventional longitudinal steel reinforcement in the plastic hinge regions of bridge piers with super-elastic shape memory alloy (SMA) could significantly reduce residual deformations. In this study, numerical investigations on the performance of SMA-reinforced concrete (RC) bridge bents to monotonic and seismic loadings are presented. Incremental dynamic analyses are conducted to compare the response of SMA RC bents with steel RC bents considering the peak and the residual deformations after seismic events. Numerical study on multiple prototype bridge bents with single and multiple piers reinforced with super-elastic SMA or conventional steel bars in plastic hinge regions is conducted. Effects of replacement of the steel rebar by SMA rebar on the performance of the bridge bents are studied. This paper presents results of the parametrical analyses on the effects of various design and geometric parameters, such as the number and geometry of piers and reinforcement ratio of the RC SMA bridge bents on its performance.     

Seismic vulnerability assessment of reinforced concrete silo considering granular material‐structure interaction

As a special shell structure, silos are used in storing a wide range of multitudinous granular materials. However, seldom have researchers assessed seismic vulnerability of the reinforced concrete (RC) silo. This paper aims at studying the seismic vulnerability assessment of a silo, which is located in Zhoushan, China. Prior to assessing the seismic vulnerability of the selected RC silo, the validation of the hypoplastic constitutive model, which is used to simulate granular materials, is studied. After discussing the validation of the hypoplastic theory, the numerical model considering granular material‐structure interaction is developed by means of the ABAQUS software. And the numerical simulation results are compared with the experimental data obtained from a shaking table test discussed in order to confirm the validation of the numerical model, which is used to study the seismic vulnerability of the RC silo. Then the seismic fragility assessment of the selected RC silo is performed using the incremental dynamic analysis. The analytical results showed that the hypoplastic theory can be used to simulate the stored materials in the silo considering the collapse property before entering plastic state of granular materials. For the design basic acceleration, the fragility curves of the selected RC silo showed that the probability of exceeding the no or light damage state was about 2.12%. For the maximum considered earthquake, the exceeding probability of no or slight and the moderate damage states was 17.63% and 1.31%, respectively. With respect of the severe and total damage state, the exceeding probabilities were almost zero. Therefore, the selected RC silo structure has enough safety stock to withstand strong earthquakes in the future. Finally, a general design procedure considering seismic fragility assessment was presented in order to provide references for other structure design. Copyright © 2016 John Wiley & Sons, Ltd.     

基于IDA的高面板堆石坝抗震性能评价

抗震性能分析能够有效估计结构在地震作用下的危险性,逐渐成为抗震安全性评价的重要方法,但由于结构的复杂性,该方法在面板堆石坝方面的应用还处于起步阶段。随着强震区大量高面板堆石坝的建设,这些高坝的安全性是必须要考虑的重大问题,因此对大坝进行抗震性能分析至关重要。增量动力分析(IDA)法作为一种抗震性能分析方法,能够全面、深入地分析在不同强度地震作用下结构性能的变化。将IDA法引入到高面板堆石坝安全评价领域,建立了高面板堆石坝地震破坏性能评价方法。根据场地条件选取了15条不同的强震动记录,以地震峰值加速度PGA为地震动参数,采用坝体地震震后变形、坝坡稳定性、面板防渗体安全为抗震性能评价指标,选取合适的性能参数,建议了高面板堆石坝各评价指标的破坏等级划分标准,通过大量非线性有限元计算,得到各性能参数的地震易损性曲线,分析了大坝在不同强度地震作用下发生破坏的概率,成果可为高面板堆石坝抗震性能设计和安全风险评估提供参考和依据。     

杆件初始缺陷对单层凯威特球面网壳地震响应影响研究

为研究杆件初始缺陷对单层凯威特球面网壳地震响应的影响,利用OpenSEES有限元程序,采用多段梁法模拟杆件初始缺陷,给出了OpenSEES模拟空间网格结构圆管杆件滞回的多段梁法建模参数合理取值,基于GB 50017—2003《钢结构设计规范》中压杆稳定系数拟合了圆管等效偏心率和正则化长细比的关系式。考虑杆件初弯曲方向随机分布,建立了不同参数单层凯威特球面网壳模型,对网壳增量动力分析的最大位移进行了比较。结果表明：当网壳处于弹性状态时,杆件缺陷对其地震响应的影响可以忽略;当网壳进入塑性状态后,杆件缺陷对其地震响应的影响不可忽略,不同杆件初弯曲方向的网壳地震响应离散程度随地震动强度提高基本呈增大趋势;地震动强度较大时,考虑杆件缺陷和结构整体缺陷的单层网壳地震响应和仅考虑整体缺陷的单层网壳地震响应差异较大,两者最大位移的相对大小并无规律性,其关键影响因素为地震作用下塑性杆件分布的离散程度。     

基于增量式互信息的图像快速匹配方法

针对传统互信息图像匹配方法中因灰度概率分布计算量大而导致匹配速度慢的问题,提出一种增量式灰度统计的图像匹配新方法。该方法在初始待匹配子图概率分布统计表的基础上,经过增量式计算避免了相邻图像块中灰度概率统计的重复性操作,大大减少了图像匹配过程中的概率统计的运算量。实验结果证明了该算法在保持互信息图像匹配优势的同时,提高了图像匹配的速度。     

基于改变比例因子的变步长最大功率跟踪算法

通过仿真模拟分析光伏电池特性,针对传统的变步长电导增量(INC)法存在无法同时满足跟踪速率和减少振荡的问题,提出了一种基于改变步长比例因子的变步长最大功率算法,实时判断工作点的状态来选择不同的步长比例因子,从而解决MPPT控制过程中动态响应和稳态波动的这一矛盾关系。仿真结果表明:改进的算法和传统的变步长INC相比,跟踪过程更快速,跟踪结果更精确,系统输出功率在最大功率点处的振荡得以有效降低,动态性能和稳态性能都更优异。     

售电侧改革下电力咨询企业新业务探索

售电侧改革带来了广阔的市场机遇,也对电力咨询行业提出了更高的服务要求。在深入分析售电侧改革的基本特征基础上,重点提出电力咨询企业服务于政策咨询与市场研究、增量配电网规划、需求侧响应服务、购售电业务咨询与功能开发等各项新型业务,为其开拓售电市场提供了有益思路。     

顶推法拆除连续梁桥导梁的设计及施工

结合佛开高速改扩建工程实例,介绍了顶推法拆除旧北江大桥主桥的方法,着重对顶推法施工中导梁的设计、施工及拼装方案进行了研究,并阐述了导梁的静载试验技术,为顺利进行主桥顶推过程提供了科学依据。     

桃花峪黄河大桥顶推施工方案设计与创新

武西高速公路桃花峪黄河大桥主桥为双塔3跨自锚式大跨度悬索桥,上部结构为整体钢箱梁.钢筋梁宽39m,纵隔板间距为18.4m,中心线梁高3.5m.全桥分为53个节段,钢箱梁质量16 180t.采用先梁后缆方案施工,钢箱梁采用54m高临时墩,多点、同步、连续顶推施工技术.具有顶推质量大,长度长,施工质量和线形控制要求高,河床摆动冲刷大等特点,在临时墩顶位移、顶推不平衡水平力控制、顶推平台的滑移方式设置等施工相对传统技术方面,有较大的提升和创新.