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1、基于机组自启停技术的电厂辅助蒸汽系统功能组设计史玲玲（广东电网公司电力科学研究院，广东 广州 510600）摘要：本文通过对机组自启停技术和功能组设计思路的介绍，着重分析华能海门电厂辅助蒸汽系统功能组的设计。设计方案对属于辅助蒸汽系统功能组的相关设备的操作顺序、相互关系、关联条件、异常情况时的程序返回和人工干预等情况作出准确的分析和划分。应用实践表明，基于机组自启停技术的电厂辅助蒸汽系统功能组设计符合运行规程要求，机组自启停技术的优势得到体现。关键词：机组自启停；功能组；辅助蒸汽系统Function Group Design of Auxiliary Steam System based on
2、 technique of Automatic Plant Startup and Shutdown SystemSHI Lingling(Guangdong Electric Power Research Institute, Guangzhou, 510600)Abstract: This paper introduces the technique of automatic plant startup and shutdown system and design ideas of function group. The function group design of auxiliary
3、 steam system is the emphasis for analyzing. In design of the function group, the operation sequences of auxiliary steam system related equipments, the relationship between the related conditions and procedures for abnormal situations return and manual intervention, etc. are accurately analyzed and
4、divided. Practical application indicates that, function group design of auxiliary steam system based on technique of automatic plant startup and shutdown system meets the requirements to operating standard, and the advantages of automatic plant startup and shutdown system are reflected.Key words: au
5、tomatic plant startup and shutdown system；function group；auxiliary steam system1 引言现代大型火力发电机组向高参数、大容量方向发展，控制系统结构变得更加复杂。对机组运行人员的操作、运行状况判断水平要求严格。因此，采用自动化水平高的控制系统，对于减少运行人员工作量，并提高设备运行的安全性有着重要意义1。目前，基于整机自启停控制思想的控制系统在国内逐渐受到关注，并在国内部分先进电厂开展应用，如粤电沙角C电厂，华能海门电厂，江苏利港电厂等。华能海门电厂采用的机组自启停系统，是这一先进机组运行管理控制概念是我国在百万千瓦机
6、组的首次应用。文中根据华能海门电厂的机组自启停整体思路，着重分析辅助蒸汽系统功能组的设计。2 机组自启停技术与功能组机组自启停系统（Automatic Plant Startup and Shutdown System，简称APS）是顺序控制系统分层金字塔结构的最高一级控制，也称为机组级控制。在机组启停时，仅需按下一个启动或停止控制键，整个机组就将按照设计的先后顺序、规定的时间和各控制子系统的工作情况，自动启停过程中的相关设备，协调机炉电各系统的控制，在少量人工干预甚至完全不用人工干预的情况下，自动地完成整台机组的启停。在国内多家大型火电厂在顺序控制系统中均设计了机组级控制，基本上实现了整套机
7、组的“一键启动”。APS给功能组自动控制方式提供控制信号。因此，APS也叫功能组自动方式控制，而功能组接受运行人员指令为功能组手动方式也叫功能组控制。功能组级是一种以一个工艺流程为主，包含有关设备在内的顺序控制。它将同一系统的有关设备按控制逻辑集合在一起，形成一个独立的整体，相对集中地进行启动或停止。如风烟系统的风烟挡板、油泵组的启停控制等。功能组级控制与机组级控制相连，其接收来自机组级控制的指令信号，并判断功能子组投运或备用。功能组级控制的操作方式可以选择自动，也可以选择手动，其控制功能包括2：接收各种模拟量信号和开关量信号，并进行信号处理和分配；报警等限值的监视、计算；单个设备的控制；过程
8、和设备的保护以及联锁；所有执行机构以及控制操作信号的生成和转换等。功能组级控制系统设计时，必须对属于这一组的全部设备的操作顺序、相互关系、关联条件、异常情况时的程序返回和人工干预等情况作出准确的分析和划分。3 基于APS的电厂辅助蒸汽系统功能组设计3.1 电厂辅助蒸汽系统单元制机组均设置辅助蒸汽系统。辅助蒸汽系统的作用是保证机组安全可靠地启动及停机，及在低负荷和异常工况下提供必要的、参数和数量都符合要求的汽源，同时向有关设备提供生产加热用汽。辅助蒸汽系统的主要功能是为机组启动时除氧器预热和锅炉上水加热、汽轮机和小机轴封、小机调试等提供用汽。机组低负荷时辅助用汽系统用汽、机组跳闸时备用汽及停机时
9、保养用汽都来自该辅助蒸汽母管。另外空气预热器吹灰、制粉系统灭火蒸汽、等离子点火热风暖风器、脱硫岛吹扫等汽源也来自辅助蒸汽系统。如图1所示为华能海门电厂1000MW汽轮机辅助蒸汽系统示意图。图1 华能海门电厂1000MW汽轮机辅助蒸汽系统示意图1除氧器加热用辅汽关断门；2除氧器再沸腾用辅汽关断门；3空预器吹灰用辅汽关断门；4等离子点火暖风器用辅汽关断门；5锅炉房点火油管路用辅汽关断门；6磨煤机A灭火蒸汽电动门；7磨煤机B灭火蒸汽电动门；8磨煤机C灭火蒸汽电动门；9磨煤机D灭火蒸汽电动门；10磨煤机E灭火蒸汽电动门；11磨煤机F灭火蒸汽电动门；12辅汽至除氧器压力调节阀；13给水泵汽机A调试/启动
10、用汽关断门；14给水泵汽机B调试/启动用汽关断门；15汽机轴封及高压缸预暖用辅汽关断门；16汽机轴封系统用辅汽关断门；17四级抽汽至辅汽联箱关断门；18低温再热蒸汽至辅汽联箱压力调节阀；19低温再热蒸汽至辅汽联箱关断门；202机组启动蒸汽进汽门；211机组启动蒸汽进汽门辅助蒸汽系统主要包括：辅助蒸汽联箱、供汽汽源、用汽支管、减温减压装置、疏水装置及其连接管道和阀门等。辅助蒸汽联箱是辅助蒸汽系统的核心部件。华能海门电厂辅汽系统为全厂提供公用汽源，每台机组设置一根压力为0.81.3MPa（g）、温度为320380的辅助蒸汽联箱。辅助蒸汽系统一般有三路汽源，分别考虑到机组启动、低负荷、正常运行及厂区
11、的用汽情况。这三路汽源是其他机组供汽或启动锅炉、本机再热蒸汽冷段（即二段抽汽）和四段抽汽。设置三路启动汽源的目的是保证供汽，减少启动供汽损失，提高启动工况的经济性。3.2 基于APS的功能组设计方案辅助蒸汽系统需要解决的关键问题是向辅汽系统核心部件（辅助蒸汽联箱）供汽前应对辅汽用户进行隔离以及供汽过程中对辅汽联箱温升率的控制。因为辅汽的用户比较多，在给辅汽联箱供汽前必须对这些用户进行隔离，避免辅汽非正常使用。图2 辅助蒸汽系统功能组画面功能组设计是通过关闭辅汽用户支路上的电动门来完成对用户的隔离。此外由于辅助蒸汽温度一般都是在300左右，因此在给辅汽联箱供汽前必须控制进汽量，防止辅汽联箱以及管
12、道金属受热不均匀而产生应力。功能组设计采用对进汽电动门进行点动中间停来控制进汽量让温度均匀上升，具体而言是让进汽电动门开5秒然后再停10分钟再开5秒如此反复直至电动门全开。这样缓慢进汽有利于管道以及联箱金属均匀受热控制温升率。功能组启动允许条件包括辅助蒸汽系统压力250且辅汽联箱压力0.5MPa，考虑到辅助蒸汽系统的三路汽源分别适用于机组启动、低负荷、正常运行及厂区用汽情况，这三路汽源只要保证有一路供应既可。因此这里是启动蒸汽进汽电动门、四抽用汽电动门、冷再至辅汽电动门任一供汽电动门全开即可。如图2所示为辅助蒸汽系统功能组画面。第1步打开辅汽疏水扩容器冷却电动门。因为辅汽系统投入初期由于管道壁
13、温比较低，因此需要打开疏水门进行疏水。这些疏水会排至疏水扩容器中，因此需要打开冷却电动门进行必要的冷却。第2步是关闭三路辅汽进汽管道先保证切断进汽源。第3步隔离辅汽系统用汽支路上的用户即关闭所有辅汽用汽隔离电动门。第4步点动打开蒸汽进汽电动门缓慢进汽，反复以每开5秒停10分钟的速率打开直至进汽电动门全开确保辅汽系统温升率控制。4 基于APS的辅助蒸汽系统功能组的应用效果2009年9月，海门电厂二号机组投产进入商业运行，从试运行到商业运行整段时间内，APS系统的优势比较突出，功能组的使用效果非常显著。APS系统的实质是电厂运行规程的程序化，功能组是APS的重要组成部分。其优势主要有以下几点3：大
14、大减轻运行人员的工作强度，避免人为操作中的各种不稳定因素，缩短系统启停时间。通过控制系统合理的参数设计，向机组的各种设备提供了可靠的、经济的启停指令。无延时地监视系统启停过程中最危险的阶段，并且可以避开潜在掉闸隐患。5 结束语华能海门电厂辅助蒸汽系统功能组基于APS控制思想，从应用效果来看，安全性、稳定性、简便性得到验证，获得了运行人员的好评。机组自启停这项技术的应用会更加成熟，功能组的设计方案也将越来越完善。随着应用的逐步扩大和经验的不断积累，机组自启停技术将助力提高大型火电厂的生产水平。参考文献：1 谢健育. 700MW机组自启停系统（APS）设计特点和应用J.内蒙古电力技术，2001，1
15、9(2):10-12.2 韦根原. 大型火电机组顺序控制与热工保护M.中国电力出版社，2008.3 冯连根，周国强. APS控制系统在河津发电厂的应用J. 山西电力，2005，3:54-58.作者单位和地址：广州市梅花路73号 广东省电力科学研究院热工室 邮编：510600史玲玲联系方式：E-mail: linyi0518电话：15915870512Editors note: Judson Jones is a meteorologist, journalist and photographer. He has freelanced with CNN for four years, cover
16、ing severe weather from tornadoes to typhoons. Follow him on Twitter: jnjonesjr (CNN) - I will always wonder what it was like to huddle around a shortwave radio and through the crackling static from space hear the faint beeps of the worlds first satellite - Sputnik. I also missed watching Neil Armst
17、rong step foot on the moon and the first space shuttle take off for the stars. Those events were way before my time.As a kid, I was fascinated with what goes on in the sky, and when NASA pulled the plug on the shuttle program I was heartbroken. Yet the privatized space race has renewed my childhood
18、dreams to reach for the stars.As a meteorologist, Ive still seen many important weather and space events, but right now, if you were sitting next to me, youd hear my foot tapping rapidly under my desk. Im anxious for the next one: a space capsule hanging from a crane in the New Mexico desert.Its lik
19、e the set for a George Lucas movie floating to the edge of space.You and I will have the chance to watch a man take a leap into an unimaginable free fall from the edge of space - live.待添加的隐藏文字内容2The (lack of) air up there Watch man jump from 96,000 feet Tuesday, I sat at work glued to the live strea
20、m of the Red Bull Stratos Mission. I watched the balloons positioned at different altitudes in the sky to test the winds, knowing that if they would just line up in a vertical straight line we would be go for launch.I feel this mission was created for me because I am also a journalist and a photogra
21、pher, but above all I live for taking a leap of faith - the feeling of pushing the envelope into uncharted territory.The guy who is going to do this, Felix Baumgartner, must have that same feeling, at a level I will never reach. However, it did not stop me from feeling his pain when a gust of swirli
22、ng wind kicked up and twisted the partially filled balloon that would take him to the upper end of our atmosphere. As soon as the 40-acre balloon, with skin no thicker than a dry cleaning bag, scraped the ground I knew it was over.How claustrophobia almost grounded supersonic skydiverWith each twist
23、, you could see the wrinkles of disappointment on the face of the current record holder and capcom (capsule communications), Col. Joe Kittinger. He hung his head low in mission control as he told Baumgartner the disappointing news: Mission aborted.The supersonic descent could happen as early as Sund
24、ay.The weather plays an important role in this mission. Starting at the ground, conditions have to be very calm - winds less than 2 mph, with no precipitation or humidity and limited cloud cover. The balloon, with capsule attached, will move through the lower level of the atmosphere (the troposphere
25、) where our day-to-day weather lives. It will climb higher than the tip of Mount Everest (5.5 miles/8.85 kilometers), drifting even higher than the cruising altitude of commercial airliners (5.6 miles/9.17 kilometers) and into the stratosphere. As he crosses the boundary layer (called the tropopause
26、), he can expect a lot of turbulence.The balloon will slowly drift to the edge of space at 120,000 feet (22.7 miles/36.53 kilometers). Here, Fearless Felix will unclip. He will roll back the door.Then, I would assume, he will slowly step out onto something resembling an Olympic diving platform.Below
27、, the Earth becomes the concrete bottom of a swimming pool that he wants to land on, but not too hard. Still, hell be traveling fast, so despite the distance, it will not be like diving into the deep end of a pool. It will be like he is diving into the shallow end.Skydiver preps for the big jumpWhen
28、 he jumps, he is expected to reach the speed of sound - 690 mph (1,110 kph) - in less than 40 seconds. Like hitting the top of the water, he will begin to slow as he approaches the more dense air closer to Earth. But this will not be enough to stop him completely.If he goes too fast or spins out of
29、control, he has a stabilization parachute that can be deployed to slow him down. His team hopes its not needed. Instead, he plans to deploy his 270-square-foot (25-square-meter) main chute at an altitude of around 5,000 feet (1,524 meters).In order to deploy this chute successfully, he will have to
30、slow to 172 mph (277 kph). He will have a reserve parachute that will open automatically if he loses consciousness at mach speeds.Even if everything goes as planned, it wont. Baumgartner still will free fall at a speed that would cause you and me to pass out, and no parachute is guaranteed to work h
31、igher than 25,000 feet (7,620 meters).It might not be the moon, but Kittinger free fell from 102,800 feet in 1960 - at the dawn of an infamous space race that captured the hearts of many. Baumgartner will attempt to break that record, a feat that boggles the mind. This is one of those monumental moments I will always remember, because there is no way Id miss this.
