1000MW机组中小汽机驱动引风机的系统配置

结合某发电厂扩建工程,就百万级超超临界机组中采用汽轮机驱动引风机的方案进行了论述.文中对与引风机汽轮机有关的蒸汽、轴封、凝结水等系统配置进行讨论,为今后大型机组的节能减排提供借鉴.     

汽轮机驱动引风机设计方案优化

为了减少厂用电,提高机组效率,提出了引风机采用汽轮机驱动的方案,并对采用背压式汽轮机和凝汽式汽轮机2 种系统设计进行了分析。同时结合华能沁北发电厂三期工程,将2 种汽轮机方案与电动驱动方案进行了技术经济比较,得出了相关比较结论,给相关的工程设计提供参考。     

1 000 MW湿冷机组主汽轮机驱动给水泵研究

对锅炉给水泵采用主汽轮机驱动方式进行了深入论述和分析,并对1 000 MW超超临界湿冷机组锅炉给水泵采用小汽轮机驱动和主汽轮机驱动2种方式进行了综合技术经济比较。分析比较结果表明：锅炉给水泵采用主汽轮机驱动方案从技术角度来讲是完全可行的;对于1 000 MW超超临界湿冷机组,给水泵采用主汽轮机驱动方式比小汽轮机驱动方式的热经济性好;虽然主汽轮机驱动方案的初始投资比小汽轮机驱动方案高,但从电厂全寿命周期20年考虑,累计节约的运行费用基本上能收回电厂增加的初始投资,而且随着煤炭资源的日益紧张,采用主汽轮机驱动给水泵方案的节能效果优势将越来越明显。     

REXA执行器电液控制系统在145 MW热电联产汽轮机上的应用

华能北京热电公司1号机组为俄罗斯乌拉尔汽轮机制造厂生产的145MW抽汽式汽轮机,采用电液并存调节系统。为提高机组的自动化水平,采用以REXA执行器为转换装置和力驱动执行机构油动机的技术方案对其进行了改造,取得了满意的效果,为同类型机组调节系统的改造提供了新途径。     

1000MW燃煤机组引风机汽轮机真空偏低原因分析及改进

为降低机组厂用电率,部分燃煤电厂引风机采用汽轮机驱动,使汽轮机冷端优化复杂化。针对国内某1 000 MW燃煤机组引风机汽轮机真空偏低的问题,结合主机冷端优化,考虑电厂实际运行中的可操作性,提出切实可行的提高方法及最佳运行方案。     

NK50/56/0型汽轮机控制系统设计应用

分析了NK50／56／0型驱动给水泵汽轮机控制系统在应用中出现的问题,提出了一种利用DCS系统资源替换WOODWARD控制系统的改造设计方案。方案的实施及应用提高了控制系统的可靠性、降低了维护量并简化系统及运行操作。为老机组控制系统的改造和新机组给水泵汽轮机控制系统的设计提供了一个可借鉴的方案。     

典型300 MW亚临界机组冲动式汽轮机反动式改造

对冲动式汽轮机和反动式汽轮机的主要特点进行了对比,提出了一种将冲动式汽轮机改造为反动式的方案,并分析了该方案在某300 MW亚临界机组上的应用效果.结果 表明:经过反动式改造后,各缸效率明显提升,机组热耗大幅下降.     

大容量空冷电厂主汽轮机同轴驱动给水泵技术研究

给水泵是机组重要辅机设备之一,研究开发新型给水泵驱动方式可以降低厂用电、简化给水泵系统、减少相关设备初投资,已经成为发展大容量超临界、超超临界空冷机组的重要研究课题,文中通过与600 MW超临界空冷发电机组给水泵电动给水泵和汽动给水泵配置方案的综合技术经济性比较,介绍了一种新型的主汽轮机同轴驱动给水泵方案,对其技术方案、设备配置和特点进行了介绍,对3种方式的初投资、经济性、年费用等进行了比较,认为主汽轮机同轴驱动给水泵方案经济性最好,并为将来600 MW超临界和1 000 MW超超临界机组给水泵驱动方式的选型提供了理论参考。     

1000MW超超临界机组引风机回热式背压机驱动的设计及实践

为了减少厂用电,提高机组效率,结合北仑电厂百万级超超临界机组的实际情况,提出了锅炉引风机采用回热式背压汽轮机驱动的方案,详细论述了系统设计,并对工程的技术经济性进行了分析。     

未来的汽轮机

<正> 日前,世界总发电量的四分之三以上是由电站汽轮机提供的(包括火电汽轮机和核电汽轮机)。一、当今的汽轮机技术水平1.核电用全转速饱和汽轮机的代表性机组是瑞士Gosgen核电站的1000MW汽轮机。2.核电用半转速饱和汽轮机的代表性机组是联邦德国Brokdorf核电站的1400MW汽轮机。3.没有中间再热的过热汽轮机的代表性机组是南非Hendrina火电站的200MW汽轮机。     

Development of a contactless measurement method for transmission line surge voltage waveform

This paper proposes a contactless method to measure a surge voltage waveform on an overhead transmission line and on a cable sheath enclosed in a corrosion‐proof layer. To measure surge voltage and current waveforms on the overhead line, the method is based on electromagnetic coupling between the overhead line and a surge sensor, composed of a closed loop which is a distributed parameter line. The surge waveform is estimated from the induced voltage to the closed loop and from a Z‐parameter theory. To measure the cable sheath voltage waveform, the method is based on electrostatic coupling between the sheath and a detecting electrode, which is portable and detachable, and is composed of quite simple components, and its potential dividing ratio is adjustable using a lumped capacitor. The proposed method is inexpensive, is easy to measure surge waveforms with reasonable accuracy, and also is applicable to surge measurement on a live line because of its contactless nature. © 2001 Scripta Technica, Electr Eng Jpn, 136(1): 9–15, 2001     

Robust method to provide exponential convergence of model parameters solving linear time-invariant plant identification problem

The scope of this research is a problem of parameters identification of a linear time-invariant plant, which (1) input signal is not frequency-rich, (2) is subjected to initial conditions and external disturbances. The memory regressor extension (MRE) scheme, in which a specially derived differential equation is used as a filter, is applied to solve the above-stated problem. Such a filter allows us to obtain a bounded regressor value, for which a condition of the initial excitation (IE) is met. Using the MRE scheme, the recursive least-squares method with the forgetting factor is used to derive an adaptation law. The following properties have been proved for the proposed approach. If the IE condition is met, then: (1) the parameter error of identification is bounded and converges to zero exponentially (if there are no external disturbances) or to a set (in the case of them) with an adjustable rate, (2) the parameters adaptation rate is a finite value. The above-mentioned properties are mathematically proved and demonstrated via simulation experiments.     

基于概率路线图法的窄道采样与轨迹优化

提出一种结合莱维飞行和概率路线图法(Lévy-probabilistic roadmap, LPRM)的路径规划算法。将莱维飞行方法应用于窄道采样,障碍物中的随机点通过莱维飞行走至自由空间,并延长碰撞测试来确保采样点位于窄道内,提升狭窄区域的采样质量与效率;为避免大量无效点的生成,在采样前先对地图进行预处理,膨胀障碍并对其进行边界提取,根据边界信息计算狭窄区域采样点数量,保证了全图采样的合理分布;进一步考虑移动机器人的实际工作情况,采用分段贝塞尔曲线对路径轨迹进行优化使其符合运动学约束,提高移动机器人的机动性。仿真实验在不同环境地图下对比了LPRM、传统概率路线图(PRM)和桥测试3种算法,结果表明LPRM算法相较两者在单一窄道环境下规划效率分别提升35.1%和32.2%,在复杂环境下其规划效率分别提升32.9%和15.5%,且提前400和100个采样点达到收敛,规划效率和成功率显著提高,总体耗时更短、路径更优,能减少移动机器人本身的能耗,提高整体工作效率。     

A genetic algorithm approach to short‐term scheduling of crude oil operations in refinery

As a type of process plant, a refinery is characterized by the interaction of discrete events and continuous processes. To schedule crude oil operations in a refinery, it is necessary to define and schedule the jobs simultaneously such that heuristics and meta‐heuristics cannot be directly applied. It is very challenging to schedule crude oil operations. To solve this problem, it is decomposed into two subproblems hierarchically. At the upper level, a refining schedule is found, while at the lower level a detailed schedule is obtained to realize the refining schedule. Given a refining schedule at the upper level, this paper studies the detailed scheduling problem at the lower level. Based on a control‐theoretic perspective, the problem is innovatively transformed to a problem of assigning charging tanks to distillers such that meta‐heuristic methods can be applied. Then, a genetic algorithm (GA) approach is developed to solve the problem. In realizing the proposed GA, based on a set of existence conditions of a feasible schedule, methods are presented to guarantee that each chromosome corresponds to a feasible schedule. An industrial case study is used to show the application of the proposed method. It shows that the method works well and is applicable to real‐life problems. © 2016 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

含铁心线圈励磁特性求取方法的探讨

为求取电力系统中含铁心线圈元件的励磁特性,选取13次多项式模拟瞬时值励磁特性,采用基于Leven-berg-Marquardt方法的非线性最小二乘法对实测数据进行参数估计以确定多项式的待定系数,从而单值确定有效值伏安特性,再转换为瞬时值励磁特性。计算实例表明该法可保证拟合精度,满足工程实际需要。     

一种实用的配电网无功运行两层优化方法研究

针对多时段动态无功优化,将控制设备动作次数转化成设备调节费用并将其计入目标函数,建立以全天网损费用与设备调节费用之和最小为目标函数的优化模型。将Fisher有序聚类算法引入到负荷曲线分段问题中,使分段后的负荷曲线尽可能贴近实际负荷水平。提出一种基于改进遗传算法和准动态规划法的两层优化算法,以获取全天控制设备的动作方案,实现多时段的协调优化。为兼顾算法的寻优速度和搜索精度,可依据电网规模灵活设置各阶段保留的最优路径数,适合于大规模系统的动态无功优化。算例表明了所提方法的实用和有效。     

煤粉燃烧排放特性数值模拟

研究燃烧污染物排放具有重要意义，数值模拟是一种有效的研究方法，该文利用数学模型，采用后处理方法，在燃烧模拟的基础上，计算了NOx在电厂锅炉炉内的分布情况，对SOx生成采用了常用的反应模型，并根据反应动力学原理，提出了SOx生成模型。在国内首次对800MW锅炉进行了计算和现场测试。其计算所得结果比较符合实际，说明所提出的模型是合理的，该研究对锅炉的设计和清洁运行具有重要的参考价值。     

并联型有源电力滤波器设计及并网冲击电流的抑制

以LCL型三相三线制并联型有源电力滤波器为研究对象,分析和建立其在d-q坐标系下的数学模型,根据瞬时无功理论,设计了一套全数字化谐波提取及补偿算法.在推导了并网冲击电流和投入时刻关系的基础上,提出一种直流侧电压分段函数控制和装置最佳点投入电网补偿的柔性并网方案,并为确保算法能够实时运行,开发了一套基于浮点型DSP TMS320F28335和定点型DSP TMS320F2812的双CPU控制系统.经50 kVA样机实验结果验证:双CPU控制系统和全数字化补偿算法保障了装置的实时性和补偿效果,柔性并网方案有效地抑制了冲击电流.     

Modelling and management of smart microgrid for rural electrification in sub-saharan Africa: The case of Nigeria

Access to electricity is still a challenge in many parts of sub-Saharan Africa. In Nigeria, over 70% of the rural dwellers do not have access to electricity. The purpose of this paper is to examine the potential of a smart microgrid for off-grid rural electrification in Nigeria. A combination of design thinking and model-based design methodology is employed to select a suitable microgrid configuration and to develop a smart microgrid model. A system consisting of a solar photovoltaic array, battery energy storage and a diesel generator is selected, and the model is developed in Simulink. Demand data from 10 rural communities in Nigeria are used to validate the performance of the model and the potential for demand management is considered. The use of energy efficient light bulbs is found to reduce the peak electricity demand of the case study communities by 42 to 76%. Combining the proposed system with the use of LED bulbs makes the system to have 56 to 81% less net present cost than a system with a diesel generator alone and incandescent light bulbs. The proposed smart microgrid is found to be more suitable for off-grid rural electrification in Nigeria than diesel generators which are currently used for off-grid electrification in Nigeria.     

Expert system for dispatch control in restoration of ehv power system after complete blackout

Present-day power systems operate with high reliability, and it is rare that a blackout will extend over an entire system swiftly and securely. This paper considers automatic power supply to loads after a complete blackout of a system. First, taking into account characteristics of generators, loads, and initial power sources, a method is proposed of allocating several generators to each load in parallel to the system and supplying power to the load sequentially. Second, to remove the imbalance between supply and demand of power, a method is proposed of adjusting the amount of supply and generation according to a present imbalance and the sum of past ones. Third, to automatically issue orders for start-up, parallel, follow-up, stand-by, and stoppage of generators, several rules for each power station are set and an expert system is made based on them. Finally, the expert system is applied to a model power system, and it is verified that it can restore loads without any trouble for a complete blackout which occur at any time of a day and in any restoration pattern.