轴流式水轮机支撑部件的结构选型与优化设计

支撑部件是轴流式水轮机组的重要部件,设计时要充分考虑支撑部件对轴流式水轮机机组安全运行的影响。运用ANSYS软件对支撑部件进行刚强度分析,从支撑结构型式的选型、支撑部件间的把合方式以及顶盖拓扑结构等3方面进行研究。分析表明:对于推力支架置于顶盖上的支撑型式,顶盖宜采用上双法兰结构,并在与支持盖的连接方式上采用上把合方式为最优化的支撑结构;而对于选择下机架支撑型式,其最优化的支撑结构为顶盖采用下双法兰结构,并在与支持盖的连接方式上采用上把合方式。     

高压电抗型启动柜的机械连锁

1机械连锁操作原理 标准的401门锁左旋到底钥匙能拔出;反之,钥匙不能拔出。利用“左旋”、“右旋”能改变部件工作状态的特性,将两把锁分别装在相关联的两个部件上,公用一把钥匙。这样,钥匙就只能插在能操作的那个部件上。要去操作另一个部件,     

大型锅炉吹管出现的问题及分析

针对ＢＰ—１０２５锅炉吹管出现的问题，采用数值分析的方法计算了该锅炉吹管过程厚壁承压部件的温度场，提出了大型锅炉采用降压吹管时应注意的问题。     

超声波和地电波检测法在局部放电检测中的运用

随着电力系统的不断发展，老旧的敞开式设备逐渐被开关柜所取代。此类柜式设备在供电可靠性和安全系数上完成了飞跃，但随之而来的问题是设备的缺陷不再是表面上能看得出的，也不是红外测温仪能直接检测的。因此，绝缘部件的局部放电检测技术显得越来越重要，已成为判断开关柜内部绝缘部件缺陷的必备手段。     

卫星电视接收系统的安装与调试(一)

卫星电视接收系统的安装与调试是先将室内外部件安装好,然后按信号流程关系,把室外部件的高频头和室内部件的接收机用传输线连接起来,并把接收机解调输出的图像视频信号和伴音信号,送到调制器调制到某一电视频道上,如图1所示。     

调峰机组金属部件问题分析及监测手段

对山东电网调峰机组金属部件的易发问题进行了分析,提出了调峰机组金属部件的安全监测手段。     

家电产品部分常见问题揭示与分析（6）——洗衣机

问题：电源软线固定螺钉与内部导线的基本绝缘接触。 [解读] 1图中螺钉是置于塑料材料上的易触及金属部件，它不能与仅用基本绝缘隔离的带电部件接触。     

承压设备安全评定技术的发展和应用

简述了安全评定技术及其在国内外的发展和应用，结合电站锅炉、压力容器、压力管道等承压部件的现状和特点，提出把安全评定新技术应用到电站承压部件，将会提高技术监督水平，促进电站机组的安全、经济运行。     

极化电磁继电器

极化电磁继电器具有最低的高度，此高度象组成继电器主要部分的电磁部件的高度一样。继电器包含一个装有电磁部件和一组静触点的底座。电磁部件包含一个一般的U型轭铁，该轭铁具有由中心铁心连接的一对并置的磁极腿，至少有一个激励线圈缠绕在中心铁心上。衔铁部件安装在带电磁铁部件的底座内，并具有伸向对面极腿上的长衔铁，以顶尖为支承，绕支点轴线在第1位置和第2位置之间运动。衔铁部件载有1个动触点，有选择性地同一个静触点接触以响应第1位置和第2位置间的衔铁运动。衔铁靠永久磁铁同磁极腿磁耦合，以使衔铁部件在电流激励励磁线圈…     

东锅440t／h超高压再热CFB锅炉技术特点、问题及对策

东锅生产的大型440t／h超高压再热循环流化床(CFB)电站锅炉，采用引进国外410t／h循环流化床锅炉技术在消化吸收后加以创新改进，各部件完全在国内设计、制造，汽轮发电机组由国内生产厂配套。本文主要介绍并分析锅炉的有关技术特点、系统配置、存在问题及对策。     

Mathematical representation of radiality constraint in distribution system reconfiguration problem

Distribution systems are most commonly operated in a radial configuration for a number of reasons. In order to impose radiality constraint in the optimal network reconfiguration problem, an efficient algorithm is introduced in this paper based on graph theory. The paper shows that the normally followed methods of imposing radiality constraint within a mixed-integer programming formulation of the reconfiguration problem may not be sufficient. The minimum-loss network reconfiguration problem is formulated using different ways to impose radiality constraint. It is shown, through simulations, that the formulated problem using the proposed method for representing radiality constraint can be solved more efficiently, as opposed to the previously proposed formulations. This results in up to 30% reduction in CPU time for the test systems used in this study.     

基于混合神经网络和遗传算法的故障诊断系统

故障诊断对于事故后快速恢复具有重要意义。多种人工智能技术在其中得以应用, 然而快速、准确的故障诊断仍是一个悬而未决的难题, 尤其在保护和断路器不正常动作或多重故障的情况下, 故障诊断更为困难。提出了一种基于神经网络 (ANN) 和遗传算法 (GA) 的故障诊断方法, 它采用三层前向神经网络执行诊断功能, 双重 GA循环优化该神经网络的结构和连接权重。第一重 GA循环用于优化神经网络结构, 第二重 GA循环进一步优化神经网络的连接权重。两重 GA循环可以搜索确定用于故障诊断的最优神经网络。有关的数学模型和算法流程在文中作了详细介绍。以4-母线简单电力系统为例, 进行了计算机仿真计算。结果表明, 基于混合神经网络和遗传算法的故障诊断系统优于传统的BP神经网络, 可以较好地解决故障诊断问题。     

基于量子进化算法的配电网开关优化配置研究

配电网的开关配置对系统的供电可靠性具有重要影响,因而对配电网的开关配置进行优化设计,使系统在满足一定可靠性指标的前提下开关总投资成本和维护成本最小很有意义。文中研究了配网开关的优化规划问题,建立了计及可靠性和经济性的开关优化规划模型,以配电网开关投资成本和维护成本最小作为优化目标,采用平均供电有效度(ASAI)作为可靠性指标。为了提高规划计算的速度,提出了一种自动开关分区段的快速求取可靠性指标方法。介绍了量子进化算法(Quantumevolutionalgorithm,简称QEA),该算法相比传统的进化算法具有更加丰富的种群,能保持优良的多样性和全局寻优能力,文章结合配网的特点,提出了基于QEA的开关优化规划求解算法。在某一系统中进行了测试,表明文中提出的方法是可行的和有效的。     

Optimal multistage modernization of power system subject to reliability and capacity requirements

This paper addresses the multistage modernization problem for power systems with series-parallel structure. The study period is divided into several stages according to demand forecast. At each stage the consumer demand distribution is predicted in the form of a cumulative load curve. Different actions, such as modifying existing equipment, changing maintenance policy, or adding new elements, may be undertaken in any system component at any stage to increase the total system capacity and/or reliability. The objective is to minimize the sum of costs of system modernization actions over the study period while satisfying reliability constraints at each stage. In order to solve the problem, a genetic algorithm is used as an optimization tool. The solution encoding technique developed allows the genetic algorithm to manipulate integer strings representing multistage system modernization planes. A solution quality index is comprised of both reliability and cost estimations. The procedure based on the universal generating function is used for evaluation of the availability of multistate series-parallel power systems. This technique allows one to estimate the effect on the entire system availability when both capacity and availability of system elements are varied. An illustrative example is presented in which the optimal expansion plan is found for a coal transportation system of a power station.     

时间频率信号的完好性监测方法研究

高精度时间频率信号稳定性和可靠性是现代导航的重要基础,直接影响系统时间基准和导航定位结果.为了保证高精度时间频率信号的稳定性和可靠性,研究时频信号完好性监测方法.并在此监测方法上,充分利用中国科学院国家授时中心生成并保持的UTC(NTSC)建立高精度时频信号监测系统.该系统可实时监测时频信号性能,检测异常,并及时响应以保证时频信号的完好性和系统时间基准的稳定性.完好性监测方法已被充分验证并应用到时频和导航系统     

Combined approach to an assessment of maintenance of electrical equipment on traction rolling stock

A possible approach to assessment of factors influencing the service-life parameters of electrical equipment on locomotives and the variants of their states is considered. The scheme proposed for the variants of states can be carried out as a system of rolling-stock maintenance. The need to increase the reliability of electronic and electrical equipment is especially acute during the operation of high-speed rolling stock, given that circuitry and structural solutions are extremely complex. In developing the computational systems and their capacity, it becomes possible to calculate large data volumes and update the problem of constructing optimal variants of state development in complex technical systems. The costs for rolling-stock maintenance and repair can be reduced by using both maintenance-free elements of rolling stock and an assembly or a part of rolling stock with a complicated structure. In connection with this, new assemblies consist of several elements with known indices of reliability and service life, but have different characteristics as a whole. An approach to technical indices of assemblies and elements as static values of certain functions is considered. A decomposition approach to an integrated reliability index and variants of planning the extents of repair and maintenance that need to be undertaken is carried out depending on the variants of states of an electromechanical assembly in rolling stock.     

配电网中辐射线路的最优分段处理

配电网中辐射线路的最优分段处理是一个需要同时考虑经济性和可靠性的非线性组合优化问题.采用结合了遗传算法的全局搜索特性和禁忌搜索算法的局部搜索特性的混合算法来求解该问题,所采用模型的目标函数同时考虑了分段开关的年投资与维护费用以及将可靠性效益转化为经济性指标的用户缺电成本.最后采用一个简单算例验证了文中方法的可行性,并在实际系统中得到了应用.     

扬州智能电网输变电状态监测系统应用研究

目前,国内设计风光互补系统配置一般采用经验来估算,这往往会造成系统装机容量严重不足或者过剩现象.风光互补独立供电系统的优化配置可看作一个多目标优化问题,2个冲突的目标是极大化供电可靠性和极小化成本.文中供电可靠性采用计算机软件模拟蓄电池组一年的每日的荷电状态值（SOC）来验算保证;成本的优化可采用遗传算法动态搜索模式,搜索计算出最小化系统配置花费.结合扬州智能电网输变电状态监测系统的具体建设,将风光互补前端供电技术在该项目中的成功应用进行了详细介绍.     

基于区间优化算法的电力系统可靠性评估逆问题模型

电力系统可靠性评估逆问题是指从已知的可靠性指标值出发求取未知的元件可靠性参数的问题,是电力系统可靠性领域一个重要的潜在研究方向。只有在待求可靠性参数个数与可靠性指标个数相等的特殊情形下,采用现有的逆问题研究方法才能取得参数的准确值。针对以上不足,首先,基于可靠性指标解析计算函数,构建逆问题的非线性方程组模型。其次,为计及已知可靠性指标个数大于、等于或小于待求参数个数的3种情形,将方程组模型转化为优化问题,建立逆问题的一般性模型。针对逆问题存在多解的情形,以可靠性参数优化为例,说明如何构建对应于具体工程问题的逆问题模型。然后,提出基于改进区间优化算法的逆问题求解方法,该方法能够在逆问题的不同情形之间进行切换,并确保求得最优解。最后,将所提方法应用于RBTS、IEEE-RTS系统和91节点系统,算例结果表明：针对逆问题的上述3种情形,采用所提方法均可有效求得准确的元件可靠性参数。     

A value-based probabilistic approach to designing urban distribution systems

Achieving high distribution reliability levels and concurrently minimizing capital costs can be viewed as a problem of optimization. Assuming given outage rates and repair times, distribution system design is the remaining factor in determining customer reliability. Including customer value of reliability in an economic analysis allows for optimization of the major components of distribution system design. Using mathematical models and simulations, a comparison of design concepts can be performed to compute the optimal feeder section length, feeder loading level, and distribution substation transformer loading level. The number of feeder ties and feeder tie placement are also optimized through the models. The overall outcome of this analysis is that capital costs can then be directed towards system improvements that will be most cost-effective in improving system reliability. This paper presents a value-based probabilistic approach to designing urban distribution systems. The value-based reliability methodology is illustrated using a practical urban distribution system of MidAmerican Energy Company.