某核电厂内部结构支承反应堆冷却剂系统的结构刚度计算

使用有限元软件ANSYS建立某核电厂反应堆厂房内部结构三维模型,并根据工艺条件图所示的设备、管道支承位置施加单位荷载以计算相应柔度矩阵,为主设备、管道在反应堆冷却剂失水事故(LOCA)和地震工况下的计算提供基本参数。     

基于改进双中心粒子群算法的电动公交车运营数量优化策略研究

针对电动公交车在一定容量约束的馈线充电的情况,采用了一种改进的双中心粒子群算法对电动公交车充电进行优化调度,以获得最大的电动公交车运营数量。首先,建立公交车充电后馈线负荷曲线峰谷差最小的模型,设公交车运营初始数量,利用改进的双中心粒子群算法进行优化。然后,根据优化结果对比该馈线容量约束修改电动公交车运营数量,重新优化,逐步逼近并最终找到最优的运营数量。改进的双中心粒子群优化算法是在原算法的基础上,增加了5条粒子运动路线,扩大了搜索精度,抑制了粒子群的早熟。同时,为了提高寻优速度,粒子的初始化是根据日负荷曲线距离馈线约束容量的远近来确定。最后以南方某城市典型的馈电线路为例进行仿真计算,结果表明,该方法具有更优的调度效果。     

基于多目标粒子群算法的电力系统环境经济调度研究

提出了一种新的多目标粒子群优化(Multi-Objective Particle Swarm Optimization, MOPSO )算法,用于求解电力系统的环境/经济调度问题。通过设计特定的约束修正因子,将不可行解修正成可行解,并在此基础上用惩罚函数法构建了新的适用于多目标粒子群的适应度函数模型。根据帕累托占优条件形成历史帕累托最优解集和全局帕累托最优解集,引入稀疏度排序法选择全局最优解,基于帕累托最优前沿的斜率特性,提出用斜率法筛选非劣解,采用基于模糊数学的满意度评价模型选择POF的折衷最优解。最后,用IEEE-30节点标准测试系统对所提算法进行了仿真测试,并与其他算法进行了对比。仿真结果表明所提算法可行、有效。     

新一代本币交易系统的综合性能测试实践

为测试多市场金融交易平台的性能,提出一种基于LoadRunner测试平台的综合性能测方法,通过搭建模拟测试环境和软件模拟大批量在线并发用户等方法,严格按照性能测试实施流程,实现了对交易平台的系统容量、系统处理能力、客户端响应时间、系统可靠性和安全性等指标的测试,取得了较好的验证和评估效果。     

含光伏和蓄能的冷热电联供系统调峰调蓄优化调度

冷热电联供(CCHP)系统的能源优化调度,可以有效提高终端用户的能源利用效率,缓解区域电网能源供需矛盾,促进分布式可再生能源的就地消纳,最大程度地实现区域电网的削峰填谷。建立了含光伏和蓄能的CCHP系统调峰调蓄优化调度数学模型,以最小化经济成本和电网供电方差为目标,引入权重系数,将多目标优化问题转化为单目标优化问题。针对光伏机组出力和负荷预测误差的随机性和不确定性,采用概率约束的形式表征其能量平衡方程。以天津中新生态城能源站CCHP系统为例进行算例分析,验证了所提模型的有效性和实用性。     

考虑重构的含可再生能源配电网电压控制模型与算法

风电、光伏等分布式电源高渗透并入10kV中压配电网,将导致系统运行经济性与电压质量等问题,若不加以有效管控,则难以充分消纳可再生能源。为实现可再生能源接入下配电网电压安全的主动管控,提出兼顾配电网结构灵活性与电压调节资源能力的机会约束双层优化模型。模型上层以配电网动态重构为手段,确保长时间尺度内的经济运行原则;下层以馈线自动调压器控制策略为对象,实现局部支路电压水平优化。为提高算法效率,利用二阶锥法松弛潮流约束,并采用库恩—塔克(KKT)条件将模型等效转化为单层决策模型。算例结果表明,所提方法通过主动重构技术协调局部电压调节资源,可实现可再生能源接入下配电网的电压安全运行控制。     

考虑污染物排放约束的传统电厂与虚拟电厂间环境经济调度模型

为有效实现分布式能源(distributed energy resource,DER)单元参与电力系统能源市场,深度挖掘负荷侧灵活供能潜力,首先建立虚拟电厂(virtual power plant,VPP)作为管理运行分布式能源的代理模型,并基于组件特性分析对虚拟电厂的外特性进行了量化;然后基于当前电力行业面临的经济环境热点问题,建立了考虑污染物排放约束的传统电厂(conventional power plant,CPP)和虚拟电厂间的环境经济调度(environmental economic dispatch,EED)二阶约束二阶规划(quadratically constraint quadratic programming,QCQP)模型;接着介绍了CPLEX优化引擎和YALMIP软件包的功能,并采用建模与求解解耦的方式来求解模型;最后对改进10机系统进行仿真计算,验证了所提模型的有效性和正确性。     

Adjustment behaviour of capital structure over the business cycles: evidence from the construction industry of Taiwan

Prior studies have found that firms may deviate from the target capital structure in the short run and adjust towards the target in the long run. However, little attention has been given to the adjustment behaviour of capital structure in the construction industry over the business cycles, in particular within the context of emerging markets. The partial adjustment model with the GMM (i.e. generalized method of moments) estimation is used to examine the adjustment behaviour of capital structure in the construction industry within the context of Taiwan during the period 1982 to 2007. The results suggest that, first, the average rate of adjustment is 26.3% of the adjustment gap between the target debt ratios and the previous debt ratios for firms in the construction industry of Taiwan. However, the average rate of adjustment towards the target debt ratios has slowed down after the Asian financial crisis of 1997. Secondly, firms with the financial constraint of over‐leverage relative to the target debt ratios have lower debt ratios than those firms with the financial constraint of under‐leverage. In addition, the difference in debt ratios between firms with the financial constraint of over‐leverage and under‐leverage has become narrower after the Asian financial crisis. Lastly, the findings suggest that macroeconomic conditions do not have a significant, negative effect on debt ratios.     

Multi-objective optimization of water distribution networks

Two multi-objective approaches to the consideration of pipe breakage data in water distribution network designs are formulated. Both models are based on the constraint method for multi-objective analysis. One model analyses the relationship between initial capital cost and subsequent repair and maintenance costs. Pipe breakage data is used to restrict the repair costs permitted in the system. The other model examines the relationships between initial pipe costs and the reliability of the pipes within the distribution network. In this second model, both the worst case and average system performance are examined in relation to the cost making model a three-objective approach. The pipe breakage data is used to restrict the expected number of failures allowed in any link. The actual number of expected breaks occurring in each link is then used to develop Poisson-based probabilities of node isolation. Application of the two approaches shows that the information obtained from such multi-objective approaches gives improved understanding into the nature of the issues behind initial cost and repair cost and initial cost and system reliability.     

湿陷性黄土地基处理中新增湿技术的应用

西北地区常年干旱少雨,地基土的天然含水率较低,一般在3.3%-10%之间,在现行地基处理施工中,地基土含水率偏低将直接影响地基处理效果,需对地基土进行增湿处理。目前,西北湿陷性黄土地基处理中增湿案例较少,本文以甘肃靖远净化站工程为依托,采用深层和浅层联合法对地基土进行增湿处理,施工设计成功解决了注水孔塌孔问题,增湿不均匀性问题,提出了增湿设计过程中影响注水孔间距的因素,注水孔间距与增湿时间之间的关系,长短注水孔的设计取值,为黄土场地增湿处理提供了借鉴。