Integrated Auto mation of Power Plant Electrical System 1Introduction
Integrated automation technology has been applied in power system substations, and decentralized and distributed technology[1]is widely used in integrated
automationsystem.Comparedtothecentralized technology,this technology has many advantages such as simple and flexible structure,high reliability,convenient installation and low cost of maintenance.However,integrated automation technology has not been widely used in power plant electrical system.Protective relay and security devices of electrical system run in a self9-governed state,which haven’t formed an integrated electrical automation system.Therefore The managing and maintaining level hang behind.Latterly more and more power plants,especially those newly constructed are interested in the automation of power plant electrical system and its relationship with traditional distributed control system(DCS.This paper analyzes the actuality of power plant electrical system,brings out a new ideal of application ofmicrocomputer9-basedintegratedautomation technology to power plant electrical system,and gives concrete realization of the program.
2The status of power plant electrical system
The electrical system discussed in this paper is mainly referred to the protection, measurement,control and automatic devices of secondary system.Main protection devices include generator protection,main transformer protection and start up/stand by transformer protection.Automatic devices include automatic regulator voltage (AVR,automatic transfer switch(ATS,faultkymograp hand protection includes high-voltage motor low-voltage system includes auto-low-voltage intelligent motor protector,breaker,DC system,etc[2]water system are not included.The characteristics of electrical system[3]operation frequency than thermal microcomputer and large-adopted.mainly on steam9-electrical
system.“Hardcable”.exchange is limited on account of the cost.impossible to accomplish more complex electrical data.Aiming at the comparatively laggard level of power plant electrical system automation,this paper analyzes the feasibility, necessity and some key points of the application of integrated automation technology to power plant electrical system.New idea using fieldbus control system technology is presented.This paper also gives the outline and detailed antomatic synchronization system(ASS.6kV auxiliary power integrative protection device, auxiliary transformer integrative protection device,feeder protection device,etc.400 V changeover device,intelligent.All these belong to the electrical system.The common systems such as coalhandling system,ash handling system and chemical are that electrical equipments have less control objects;lowersystem devices.Electrical devices have high reliability and swift action time.The technology level of individual electrical device is high.Presently,16or32bit single-chip scale programmable logic chip are used to build embedded system.Technologies of AC sampling and digital signal process are also widely DCS is widely used in power plants,and it fulfills basic operation and control functions.DCS concerns boiler system meanwhile little on Traditionally,control and signal exchange between DCS and electrical system is through this connection mode needs manycables,and the cost is high.Besides,the information It is electric operation management or achieve deep application of Since DCS is the most important system in power
3Feasibility Analysis of Electrical System Integrated Automation
The improvement of electrical system automation is based on integrated automation and field bus or industrial Ethernet technology.
Microcomputer9-based protection and automation devices are widely used in power plant electrical system.The measure,logic judge,action,record and man9-machine interface function can be done by software.Moreover,all these devices have
communication interface,they can exchange information with master system or with each other through field bus.
Fieldbus technology has been widely used in industry and electric power field, and it has been paid more and more attention.The technology in communication
rate,communication distance and anti jamming capability has been improved.Many sorts of standards have been formed,such as Profibus advocated by Siemens,FF by ABB,CAN originated from automobile industry and Lon works brought forward by Echelon company.They are all influential fieldbus technology and applied in industry automation area[4].Recently,industrial Ethernet network becomes new hotspot.
The application of microcomputer-based devices of electrical system,fieldbus or industrial Ethernet technology and communication capability provided by DCS system bring powerful support for the integrated automation of power plant electrical system.
4Real inaction of Integrated Automation in Electrical System Electrical system integrated automation is to connect foregoing many protective relay and automation devices by fieldbus and then connect them to DCS system and (possibleelectrical workstation through communication devices.The electrical workstation implements all the electrical application such as monitoring and maintenance function,and the basic Control function is accomplished by DCS system using“hard cable”.With the development of technology,the control function can also be fulfilled by
communication.Thereare two main problems in building integrated electrical automation system.One is how to build the electrical system network;the other is how to connect electrical system with DCS.Fieldbus standard is the main problem in building the network.Due to the protection and automation devices produced by different manufacturers,the physical layer and communication protocol may be different,so the devices cannot be connected simply.Since it is difficult to unify the fieldbus standard,one way to solve this problem is to divide electrical system into several
subsystems.According to the electrical system feature,the subsystem can be divided into6kV subsystem,400V subsystem,generator9-transformer protection subsystem and AVR subsystem
etc.Each subsystem supports the same fieldbus standard.For example,feeder protection,motor protection,transformer protection on6kV bus must support one kind of standard.Protections of400V System or intelligent circuit breaker use the same standard.Generator transformer protection and AVR can have the same or different standards.
5Conclusion
Adopting integrated automation of power plant electrical system is the tendency of improving the automation level of power plant,especially
improving electric operation management level.It will save the investment and improve the reliability.Microcomputer protection,automatic device,mature
communication and fieldbus technology are the technical guarantees for
integrated automation of electrical system.This paper puts forward two schemes of integrated automation of electrical system.But the modes of connecting with
DCS,standard of filedbus and structureof communication network,are still under research and need more practice.
发电厂电气系统综合自动化 1引言
综合自动化系统已经被应用于变电站系统中,并且分散分配技术也被广泛地用于综合自动化系统中。与集中的技术相比较这种技术有许多的优点,比如:它有简单和柔韧的结构,高的可靠性,方便的安装和较低的成本。
然而,综合自动化技术并没有广泛的用于发电厂电气系统中。电力系统中起保护作用的继电器和其他安全设备处于半自动运行状态,并没有实现综合自动化。因此,管理和维持高水平的工作就落后了。后来,越来越多的电厂特别是那些新建的电厂热忠于电气综合自动化系统而不是传统的集散控制系统。这篇论文分析的是发电
厂电气系统的现状以及提出了基于微型计算机技术的发电厂电气系统综合自动化的理想应用程序,并给出了具体实现方案
2发电厂电气系统的现状
电气系统自动化的进步是建立在综合自动化和现场总线或以太网络工艺学基础之上的。
以微型计算机为基础的保护和自动化设备被广泛地应用在电厂电气系统中。测量,逻辑判断,动作记录和人-机界面的功能都可以由软件来完成。并且,所有这些设备都具有通信界面,能够和主系统或其他系统之间通过现场总线进行信息交换。
现场总线控制技术目前已被广泛用于工业和电力系统中,并且这项技术越来越受到重视。现场总线控制系统的通信速率,通信距离,抗干扰能力都有了极大的改善。其许多标准也被制定,如西门子公司的Profibus和ABB公司的FF标准等。这些标准都是很有影响的现场总线技术,而且在工业自动化领域有广泛的应用。现如今工业以太网络变成了新的热点。
以微型计算机为基础的电气系统,现场总线系统或者以太网络技术的应用程序和通信功能由给发电厂综合自动化提供支持的集散控制系统提供。
3电力系统综合自动化可行性分析
电力系统的综合自动化先要通过现场总线将用于保护的继电器和自动装置 连接起来，然后把他们连接到集散控制系统再通过通信设备与可能的电站相连。 电站执行一个比如测量或者维护的程序时， 这种基本的操作功能由集散控制系统 来完成。随着技术的发展，这些控制功能也可以由通讯手段来实现。 建立电力系统综合自动化有两个主要的问题，一是如何建立电力系统的网 络，另一个是如何使电力系统与集散控制系统相连。 现场总线标准是建立网络的主要问题。 由于保护和自动装置由不同的厂家生 产， 所以其物理上的层和通信协议可能会有所差异，这样就使得设备之间不可能 被简单的联系起来。 因为要统一现场总线系统很困难， 解决这一问题的一个方法是把电力系统分 割成一些子系统。根据电力系统的
功能这些子系统被分为 6 千伏子系统，400 伏 子系统，变压器保护子系统和 AVR 子系统等等。每一个子系统支持一种相同的 现场总线标准。举例来说，线路保护、电动机保护、变压器保护在 6 千伏电压等 级上必须支持同一个标准。400 伏系统的保护或者智能断路器要用同一种标准。 发电机变压器保护和 AVR 应该用同一标准。这些子系统可以单独地和集散控制 系统相连，或者在连接了一种特别的通信控制器之后再与集散控制系统相连。 4 总 结 采用电力系统综合自动化是提高电厂自动化水平的趋势， 特别是改善电厂的 管理水平。这将减少投资提高可靠性，微机保护，成熟的通信和现场总线技术是 电气系统综合自动化的技术保证。 这篇论文提出了电气系统综合自动化两个系统 的问题。但是与集散控制系统之间的连接，现场总线的标准，通信网络的结构还 仍然处于研究和关注中。
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