风力发电机组主机架结构仿真优化方法

主机架是风力发电机组中重要的组成部件之一,其轻量化设计对整机产品的竞争力意义重大。基于变密度法开发了一种针对主机架的结构仿真优化方法,综合考虑了风机整体部件与主机架铸造工艺的影响,采用GAP单元进行轴承滚动体的等效简化,可真实地模拟轴承载荷传递机制。利用该方法成功对某大兆瓦风力发电机组的主机架结构进行拓扑优化设计,得到概念三维结构,并在三维重构后辅以极限强度分析和形状优化分析,进一步精细化修改与设计,从而得到了相对减重9%且可投入工业使用的轻量化主机架。该结构仿真优化方法对风电机组中主机架的轻量化设计有一定的可行性。     

基于免疫遗传算法的风力发电机组变增益PI控制器参数整定与优化

针对风力发电机组控制器参数在设计和优化过程中不易计算和整定的问题,首先通过Bladed软件模型线性化计算得出适用于参数整定和优化的风力发电机组线性化模型,然后基于免疫遗传算法整定PI控制器参数,根据风电场风速统计概率与Bladed软件辨识参数对普通和变增益PI控制器相关参数进行优化计算,建立了一套基于Bladed软件的风力发电机组变增益PI控制器参数整定与优化方法.结果表明:所提出的方法能够对风力发电机组变增益PI控制器参数进行有效的整定和优化,可为风力发电机组变增益PI控制器的设计与优化提供指导.     

某核电站汽轮发电机组振动保护优化探讨

针对某核电汽轮发电机组振动保护存在的问题,通过调研国内核电机组振动保护设置情况,分析国内振动保护设置的几种典型情况,得出汽轮发电机组采用轴振组合逻辑的合理性,并对汽轮发电机组振动延时问题进行了探讨,给出了建议,有效解决了问题。研究成果可为同类机组的振动保护设置提供参考。     

地区电网无功电压优化控制系统

介绍一种基于改进遗传算法与专家系统相结合的地区电网无功电压优化控制系统。该系统对简单遗传算法进行了一定的改进,并将其应用于地区电网的无功优化控制,与此同时,将基于灵敏度分析的专家系统应用于地区电网的电压校正控制。同时分析了影响该系统运行的若干因素,并提出相应的措施。     

风电场风力发电机组优化选型

基于蒙特卡罗方法建立风力发电机组的概率性模型,该模型充分考虑了风能随机性和发电设备被迫停运等随机性因素,能准确估算风力发电机组的年发电量、容量系数等经济指标;并对各种待选机组进行技术经济分析,实现机组优化选型。文中结合算例,研究风电机组参数对容量系数的影响,选择与实际风电场相匹配的风电机组。算例表明这种方法是可行的,具有实用价值。     

国产200MW汽轮发电机组三油楔轴承和椭圆轴承稳定性的比较和分析

阐述了轴承的稳定性判据。分析了国产200MW机组轴承的稳定性。介绍了国内外大机组轴承型式及其稳定性。对徐州电厂6号机组轴承改型前后的稳定性作了比较,指出,应使用稳定性较好的椭圆轴承。     

宁波电网无功优化及自动电压控制研究

以宁波电网AVC系统为研究背景,对无功优化实用化的相关问题进行研究。提出了解决无功优化配置方案,并利用宁波电网的实际数据进行计算,给出分析结论。结果表明,宁波电网AVC系统采用的分支定界法能有效地解决混合整数问题,可以满足闭环控制的实时性要求,保证控制策略的完备性、可靠性、快速性以及全局最优性,在实际电网运行中能够发挥较大作用。     

优化联合循环发电机组起机方式的细化判据

把联合循环发电机组起机过程划分为4个阶段,分析得出每个阶段的细化判据,方便了对不同机组进行定量优化,增强了可操作性,并且确定了求解最佳燃机负荷的方法。     

采暖系统分阶段质调节最佳流量比的确定方法

从节能角度出发 ,对供暖系统采用分阶段变流量质调节进行了优化运行分析 ,并以北方几个典型城市为例确定了其最佳流量比的计算方法。     

Optimization method for metal-forming processes

The paper presents a general-purpose optimization method for metal-forming processes by plastic deformation based on their modelling as thermodynamic processes with entropy generation minimization. To this purpose, equations have been formulated describing a thermodynamic system consisting of two subsystems: a tool and a workpiece which is a basic feature of each metal-forming process. A mathematical model of the thermodynamic system has been derived based on fundamental equations in continuum mechanics related to a deformable solid and the basic laws of thermodynamics. The mathematical model describes the phenomena related to the thermomechanical strength of the tool; the energy balance of the system; displacements and deformation in the tool–workpiece system due to mechanical and temperature factors, etc. On the basis of the second law of thermodynamics, entropy generation has been defined as a generalized optimization criterion and its functional has been synthesized containing the tensor functions of stresses and of strain velocities, the scalar functions of temperatures and the relative velocities of the two media. A summarized algorithm for entropy generation minimization has been proposed and illustrated by a numerical example.     

一种配电网的实用谐波电压计算方法研究

分布光伏接入配电网既可以满足用户定制电能的需求、提高用户用电可靠性,又可以节省配电网扩容成本。与此同时,通过电力电子设备接入的分布式光伏也为配电网的电能质量带来新的影响。文章分析了分布式光伏的谐波特性,在此基础上提出了含分布式光伏的配电网模型,通过此模型分析了含分布式光伏的配电网的谐波电压分布。     

串联型集成光伏组件光伏系统的运行电压优化

在串联分布式光伏系统中,若母线电压为固定值,易使分布式最大功率跟踪控制(Distributed Maximum Power Point Tracking,DMPPT)失效,造成功率的损失。通过逆变器可调节母线电压,但调节能力受电网电压的限制。因此,提出了一种新型的电路结构,在光伏组件串联侧和逆变器之间添加全局功率优化器(Global Power Optimizer,GPO),构建串联运行总线,消除了逆变器对原母线电压范围的影响。并在此拓扑基础上,提出了一种变串联运行电压功率优化算法,通过对串联运行电压进行周期性调节,提升了最大功率跟踪控制的性能。仿真结果表明,在光照严重不均的情况下,系统依然快速、稳定的工作在最大功率点处。     

工厂低压无功补偿方式优化的思考

对当前大多工厂的单一低压无功补偿方式利弊关系进行了分析,提出改革优化设想,采用无功就地补偿为主,车间补偿为辅,配电房集中弥补平衡全厂无功分级相结合的补偿方式。     

Statistical voltage quality assessment method for grids with wind power generation

The impact of wind generators on voltage control of the network has been analysed via a statistical approach. A probabilistic model was developed by taking into consideration the stochastic nature of the wind and the availability status of the network elements. The proposed statistical method estimates the voltage deviation at the point of common coupling and its probability of occurrence. An index, termed significant level of voltage deviation, has also been proposed to aid in evaluating strategies for mitigating voltage quality problems. Numerical case study is presented to illustrate the proposed method and to compare its performance against other methods.     

考虑电压稳定裕度的机组组合新方法

介绍了通过采用基于时段的优化算法求解考虑电压稳定裕度约束的机组组合,校验各时段的电压稳定裕度,并根据机组耗量优先级增减机组,使其满足相应的约束,针对该算法在处理爬坡约束上的缺陷提出了一种快速简便的修正方法。最后,采用IEEE 30节点算例论证上述方法的可行性和合理性。     

一种新的电压调整器试验方法

1 前言 电压调整器的作用是保证辅助发电机输出电压的稳定.为了满足实际运用的要求,使电压调整器以最佳的性能状态装车使用,需要用相关的试验设备(例如电压调整器试验台)来检测.     

Transient-boundary voltage method for measurement of equivalent circuit components of rechargeable batteries

A method is presented for measuring the equivalent circuit components of rechargeable batteries. The temporal discharge-rest-charge-rest sequence of a rechargeable battery is described, using the principles of transient circuit analysis, to derive equations for the battery voltage as a function of time during voltage transients and at the boundaries at transitions between transient phases. The equations lead to a new measurement method for battery characterization. The equivalent circuit of the battery is described as an ideal voltage source in series with a resistor and the parallel combination of a resistor and a capacitor. The battery model uses different values of resistance and capacitance, in the parallel combination, during the different phases of the discharge-rest-charge-rest sequence. The method is used to measure the circuit parameters of a nickel-cadmium battery.     

A voltage regulation method for dispersed grid-connected PV systems under high-density connection

This paper describes a voltage regulation method for dispersed grid-connected PV systems under high-density connection. In the near future, many PV systems will be connected to distribution systems. The reverse power flow of the grid-connected PV systems will raise line voltage to the upper limit of the legal voltage range. In the first part of this paper we examine the voltage characteristics of a distribution system under high-density connection, while the second part of the paper describes a voltage regulation method for high-density PV connections, using reactive power proportional to global irradiance. The results of tests clearly demonstrate a restraining effect on voltage during the daytime and a smoothing effect on voltage fluctuation.