大型电站稀相气力飞灰输送控制系统及其应用

介绍了气力除灰的工艺流程与控制原理,除灰控制系统的总体设计,分析稀相飞灰输送系统应用中的问题,提出稀相除灰控制系统的改进设计.     

分散型控制系统在日照电厂的应用

0 引言 日照电厂一期工程有2台350MW机组,主设备从国外购买,控制方式以DCS控制为主,辅以PLC控制.其中,机组绝大部分设备采用SIEMENS的分散型控制系统Teleperm-XP.对其监理,并与其它控制系统进行通信.在辅助设备中,如除灰除渣石子煤系统、吹灰系统、凝水精处理系统、凝汽器胶球清洗系统、水侧及汽侧真空泵、小机盘车、大机跳闸、小机跳闸等相对独立的系统中,各自独立配备PLC进行控制.     

除灰、脱硫控制一体化方案研究

对长兴电厂除灰PLC、脱硫DCS系统的控制组网作了介绍,根据系统的各自特点和维护情况提出了除灰,脱硫控制一体化构想.在一体化构想中,重点介绍了除灰脱硫的DCS一体化推荐方案.     

气力输送技术及其智能时间控制系统在燃煤电厂的应用

随着国家对环境保护工作的重视和社会对电厂粉煤灰的综合利用,当前新建机组都采用了干式除灰,气力输灰技术作为一种高效经济的干式除灰方式,在燃煤电厂得到了越来越广泛的应用。在气力输灰的运行控制方式中,先后出现过时间控制方式、仓泵料位计控制方式、灰斗料位计控制方式、时间加料位控制方式等多种控制方案。在本文中,介绍气力输灰的运行原理及其全新的控制模式-ITC智能时间控制系统。     

关于除灰系统PLC设计应用的几点意见

在未来的大型电站建设中，输灰系统自动化程度愈来愈高。它是一个集火工、机械、电气、控制等一体化的一个新型专业。本仅以全进口的外高桥电厂4×300MW集中除灰控制系统为倒，剖析其应用原理及设计方法，并对其PLC控制系统的设计与接口技术提出几点想法及建议。     

PLC在电厂干除灰系统中的应用和分析

干除灰逐渐成为电厂除灰方式的主流。文章在详细阐述了干除灰系统工作原理及可编程逻辑控制器PLC的工作原理的基础上,设计了PLC控制系统。系统中,PLC可根据料位计传输过来的灰粉位置信号(高、正常、低)和仓泵上方的电接点压力表指示压力值信号,采取相应的处理措施。采用PLC的干除灰系统抗干扰能力强,操作方便,且大幅度提高了粉煤灰的综合利用率,产生了良好的社会效益和环境效益。     

核电站除盐水PLC控制系统设计

通过对核电站除盐水生产及分配系统工艺流程的研究,提出了除盐水使用PLC控制的自动控制方案.选用西门子S7-400型PLC,针对国内某在建核电站除盐水生产及分配系统,设计了一套控制系统,实现了工艺上的控制要求.并介绍了其控制系统的硬件选型、组态,控制方案以及一些特殊反馈信号的处理方法,为以后核电站除盐水控制系统的设计打下...     

多泵制正压浓相气力输灰系统的PLC设计

电厂粉煤灰输送系统的性能好坏,很大程度上取决于其控制系统的性能,控制策略的落后及控制系统的不稳定,将严重制约着输灰系统的正常运行,从而影响火电厂的生产运行.本文根据某发电公司2台330MW机组的控制性能要求,采用可编程控制器PLC实现了正压浓相气力输灰控制系统的开发设计.系统设计具有抗干扰能力强,稳定性好,使用寿命长,扩展方便等优点,同时系统具有远程软件升级及远程故障诊断等功能.     

大型机组"飞灰/底渣岛"自控系统的应用与改进

以2×600MW机组除灰排渣系统为例,简要剖析了该系统的工艺流程、以PLC为基础的控制系统的基本配置和主要特点,重点介绍了与控制系统相匹配的主要设备和仪表的选型及要求,还介绍了在系统调试、投运过程中发现原设计方案存在的问题和解决此类问题的措施.     

PLC在除灰系统改造中的应用

文章主要介绍了PLC技术在电厂除灰集中控制系统的应用。分析了PLC系统在实际应用中存在的问题。     

煤矿井下安全监控分站的设计及其仿真实现

为了设计一种具有低成本、低功耗、易操作、功能强且可靠性高的煤矿井下安全分站,针对煤矿安全生产实际,文章提出了采用MCS-51系列单片机为核心、具有CAN总线通信接口的煤矿井下安全监控分站的设计方案;首先给出煤矿井下安全监控分站的整体构架设计,然后着重阐述模拟量输入信号处理系统的设计过程,最后说明单片机最小系统及其键盘、显示、报警、通信等各个组成部分的设计;为验证设计方案的可行性与有效性,使用Proteus软件对设计内容进行仿真验证,设计的煤矿井下安全监控分站具有瓦斯、温度等模拟量参数超标报警功能和电机开停、风门开闭等开关量指示功能;仿真结果表明:设计的煤矿井下安全监控分站具有一定的实际应用价值.     

Call for Papers The 6^th International Conference on Grid and Cooperative Computing

Recent years have seen rapid advances in various grid-related technologies, middleware, and applications. The GCC conference has become one of the largest scientific events worldwide in grid and cooperative computing. The 6th international conference on grid and cooperative computing (GCC2007) Sponsored by China Computer Federation (CCF),Institute of Computing Technology, Chinese Academy of Sciences (ICT) and Xinjiang University ,and in Cooperation with IEEE Computer Soceity ,is to be held from August 16 to 18, 2007 in Urumchi, Xinjiang, China.     

View-based model-driven architecture for enhancing maintainability of data access services

In modern service-oriented architectures, database access is done by a special type of services, the so-called data access services (DAS). Though, particularly in data-intensive applications, using and developing DAS are very common today, the link between the DAS and their implementation, e.g. a layer of data access objects (DAOs) encapsulating the database queries, still is not sufficiently elaborated, yet. As a result, as the number of DAS grows, finding the desired DAS for reuse and/or associated documentation can become an impossible task. In this paper we focus on bridging this gap between the DAS and their implementation by presenting a view-based, model-driven data access architecture (VMDA) managing models of the DAS, DAOs and database queries in a queryable manner. Our models support tailored views of different stakeholders and are scalable with all types of DAS implementations. In this paper we show that our view-based and model driven architecture approach can enhance software development productivity and maintainability by improving DAS documentation. Moreover, our VMDA opens a wide range of applications such as evaluating DAS usage for DAS performance optimization. Furthermore, we provide tool support and illustrate the applicability of our VMDA in a large-scale case study. Finally, we quantitatively prove that our approach performs with acceptable response times.     

A pragmatic multi-method investigation of discrepant technological events: Coping,attributions, and ‘accidental’ learning

Discrepant technological events or situations that entail a problem, a misunderstanding or a difficulty with the Information Technology (IT) being employed, are common in the workplace, and can lead to frustration and avoidance behaviors. Little is known, however, about how individuals cope with these events. This paper examines these events by using a multi-method pragmatic approach informed by coping theory. The results of two studies – a critical incident study and an experiment – serve to build and test, respectively, a theoretical model that posits that individuals use a variety of strategies when dealing with these events: they experience negative emotions, make external attributions, and adopt engagement coping strategies directed at solving the event, eventually switching to a disengagement coping strategy when they feel they have no control over the situation. Furthermore, users’ efforts may result in ‘accidental’ learning as they try to overcome the discrepant IT events through engagement coping. The paper ends with a discussion of the results in light of existing literature, future opportunities for research, and implications for practice.     

The Distributed Time-Triggered Simulation Scheme: Core Principles and Supporting Execution Engine

Distributed real-time simulation is a young technology field but its practice is under increasing demands. In recent years the author and his collaborators have been establishing a new approach called the distributed time-triggered simulation (DTS) scheme which is conceptually simple and easy to use but widely applicable. The concept was initiated in the course of developing a new-generation object-oriented real-time programming scheme called the time-triggered message-triggered object (TMO) programming scheme. Some fundamental issues inherent in distributed real-time simulation that were learned during recent experimental studies are discussed along with some approaches for resolving the issues. An execution engine developed to support both the TMOs engaged in control computation and the TMOs engaged in DTS is also discussed along with its possible extensions that will enable significantly larger-scale DTSs.     

Software-Konfigurationsmanagement in großen Softwareprojekten

Zusammenfassung Mit zunehmender Größe der Softwaresysteme verschärfen sich die für die Software-Herstellung typischen Probleme: Beherrschen großer Objektmengen, Erhalten der Systemkonsistenz, Kontrolle der ständigen Änderungseinflüsse und Gewährleisten einer langen Lebensdauer. Die Disziplin Konfigurationsmanagement bildet den methodischen Ansatz, diese Probleme besser zu beherrschen. Software-Konfigurationsmanagement faßt die Herstellung von Softwaresystemen als eine Abfolge von kontrollierten Änderungen an gesicherten Zwischen- und Endergebnissen auf. Dargestellt werden die Objekte und Funktionen des Software-Konfigurationsmanagements sowie die hierfür in großen Software-Projekten benötigten Methoden, Instanzen und Hilfsmittel.     

Information for Authors

正http://www.zju.edu.cn/jzus http://www.springerlink.com Aim The Journals of Zhejiang University-SCIENCE(A/B/C)are edited by the international board of distinguished Chinese and foreign scientists,and are aimed to present the latest developments and achievements in scientific research in China and     

Editorial:Brain-machine interface(BMI) and cyborg intelligence

正Brain-machine interfaces(BMIs)aim at building a direct communication pathway between the brain and an external device,and represent an area of research where significant progress has been made during the past decade.Based on BMIs,mind information can be read out by neural signals to control     

Information for Authors

正http://www.zju.edu.cn/jzus http://www.springerlink.com Aim The Journals of Zhejiang University-SCIENCE(A/B/C)are edited by the international board of distinguished Chinese and foreign scientists,and are aimed to present the latest developments and achievements in scientific research in China and overseas to the world’s scientific circles,especially to stimulate     

SCIENCE CHINA Information Sciences SUBJECT INDEX TO VOLUME 57(2014)

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