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I. The start-up and development of DCS In the first half of 1985, the author found the article “Microprocessor control of industrial steam turbines†in the “Electricl Review†Vo1.216Nno.325Jan1985. Two 70MW steam extraction turbines in a steel rolling mill located in the Ingram Steel District of East Chicago, United States, are using the latest Westinghouse Distributed Processing Family (WDPF) features. After the translation of the school published "Jilin Electric Power Technology" in 1986 the first period P60 ~ 63.
 In the second half of 1985, the author copied a copy of “Microcomputer Control of Industrial Steam Turbine†to the then Ministry of Water Resources Electric Power Planning and Design Institute.
 In 1985, the Power Planning and Design Institute approved that the 300MW unit of Wangting Power Plant selects WDPF of the Westinghouse Company for DCS pilot application to realize the functions of DAS and MCS; at the same time, Huaneng International When the power development company imported complete sets of power generation equipment for 300 MW units, it also imported DCS-based control systems [2]. After several years of installation and commissioning, the DCSs of these power plants were all put into production at the same time randomly to meet the operational requirements of the large units and solve the reliability problems that users were concerned about. Then they began to be applied and promoted on the 300MW units, but the function was only limited to DAS. , MCS and sequential control system (SCS), while also retaining more analog instruments and hard-handling equipment. Except for complete sets of imported power station equipment, most of the DCSs used have been based on products produced by domestic enterprises and foreign famous brand manufacturers (joint ventures or technology introduction), research on power systems,
Debugging units participate in programming and debugging. After more than ten years of application, mature experience has been achieved and the scope of its functions and applications is being further expanded. For example, in the past, the thermal process monitoring and control of DCS only for boilers and steam turbines has been applied to the generation, distribution, and power supply of electrical generator sets. Most domestic DCS suppliers have also mastered the boiler furnace safety monitoring system (FSSS) and steam turbine digital electro-hydraulic control system (DEH) that were designed and supplied by a professional company in the past, so that the DCS function can cover the entire power supply. The whole process.
The units that are designed and put into operation at this stage are, in addition to a few emergency shutdown buttons, cancelled conventional meters and hard hand exercises. Practice has proved that DCS is reliable. As long as the software is well-designed, it can fully ensure the safe operation of the unit and greatly simplify the automation system. The use of a display (CRT) console with a large-screen display instead of the original large unit control panel greatly reduced the space occupied and the control room area, and also created conditions for reducing the number of operating personnel.
 In 1992, the Leading Group of Thermal Engineering Automation of the Ministry of Energy, based on the maturity and performance of several imported DCS and cooperation with domestic manufacturers, recommended six models (INFI-90, WDPF, TELEPERM-ME, MAX 1000, PROCONTROL-P, HIACS-3000) DCS as a preferred domestic engineering variety.
6 On June 6, 2002, the State Power Corporation formally abolished the 6 types [2] of DCS recommended in 1992 in the cleanup of past documents.
Based on the experimental application of multiple power plants, the domestic DCS has been improved or improved to reach or approach the level of similar DCS of foreign manufacturers, and has been widely used in the reconstruction of 200, 300 MW units or in new construction projects. It is welcomed and praised by power plants. And its price is lower than foreign imported products.
Second, the composition of DCS At present, DCS can be roughly divided into three. The first is a multi-function controller-based distributed control system; the second is a distributed control system based on a programmable logic controller (PLC); and the third is a distributed control system based on a PC-based bus.
In the future, decentralized control systems based on fieldbus technology based distributed control systems or power plant information monitoring and management will emerge.
Third, DCS and its function application
3.1 Application of DCS Because DCS has the characteristics of function dispersion, data sharing, and redundancy, its reliability is high, so it has been widely used in power plants and substations. However, substations and some scholars are not called distributed control systems (DCS). They are called distributed control systems. They are also called hierarchical distributed monitoring systems.
Why did the DCS of the thermal control plant of the Thermal Power Plant design "decentralized control system"? Because at the time the article translated DCS into Chinese as "centralized decentralized control system", "distributed control system", "distributed monitoring system", " Distributed Control System, "Distributed Control System" and "Distributed Control System". These names are from the English Distributed Control System. In order to facilitate the writing of names into procedures and regulations, they are finally collectively referred to as distributed control systems (abbreviated as DCS).
From 1985 to 2001, domestic thermal power plants have adopted 229 sets of DCS (excluding small DCS), of which 176 sets are for 300MW and above, with 14 models.
At the end of 1987, our institute undertook the construction design of the 200MW unit of the third phase of Qijiang Power Plant. Our institute made a preliminary design of the Northeast Institute's thermal control professional: Solar (initial review changed to microcomputer) and programmable regulator. The estimated price of the package is used dry. After the economic and technological comparisons of multiple projects, the provincial power board discussed and passed the plan, approved the adoption of medium-sized DCS, and realized DAS and MCS functions. Although according to the design at that time it was a super-standard, but due to the use of initial funding, the control level of the power plant was not only improved, but also a sum of RMB 385,000 to 445,000 was saved after the design was completed (due to DAS and MCS transmitter signals. Share, save the cable, transmitter, distributor price 147,500 yuan; save the price of 21 sets of temperature transmitters 16,800 yuan; due to 40 programmable regulators price difference is 14 to 200,000 yuan; transmitter The incoming signal goes directly to DCS, saving the distributor's price of 80.94 million yuan.) At the same time, this is the first design unit of the home-made 200MW unit to realize the coordinated control system of the furnace, which lays the foundation for the realization of provincial dispatch or the control of the Eastern Power Dispatch 200MW unit.
 At the national power plant monitoring computer application experience exchange meeting held in Qingdao in 1991, the design summary of DCS application for 200MW units in Qijiang Power Plant was first recommended by the conference, which played a role in the development of computer control technology in thermal power plants in China. .
In recent years, the integration of electrical control into DCS has been piloted and gradually promoted. A large number of old units also use DCS for transformation.
3.2 Application of DCS Function  The DCS function is gradually developed from DAS, MCS to FSSS, DEH, SCS, BPS, ECS, etc. The author believes that it is also feasible to incorporate remote control into DCS. In recent years, FCS and SIS have been studied.
 3.2.1 Automatic Control System (Analog Control System-MCS)
 3.2.2 Data Acquisition System (DAS)
 3.2.3 Sequence Control System (SCS)
 3.2.4 boiler furnace safety monitoring system (FSSS)
 3.2.5 Electrical Control System (ECS)
 3.2.6 Steam Digital Electrohydraulic Control System (DEH)
 3.2.7 Steam Turbine Bypass Control System (BPS)
 3.2.8 Steam Turbine Safety Monitoring/Protection System (TSI/ETS)
 3.2.9 Telecontrol System 3.2.10 Fieldbus System (FCS)
3.2.11 Power Plant Information Supervision System (SIS)
IV. Development of DCS in the future  The DCS structure is divided vertically and can be divided into process control level, process management level, production management level, and operation management level. At present, the application function of DCS continues to expand, and the development of DCS is extending upwards and downwards, extending upwards to the SIS, and down to the fieldbus. Disperse DCS completely.
4.1 Fieldbus Technology DCS
The emergence of fieldbus (FB) technology is an extension of DCS to the bottom layer. For a simple control system, the two-way exchange of digital information between field devices (intelligent instruments) via fieldbus (shielded twisted-pair copper cable) enables automatic control and saves cables. Unlike in the past, every analog signal was sent to the cabinet of the control room by cable. The analog quantity of the control system must be processed by the controller's CPU and then sent to the site's actuator. 
4.1.1 Fieldbus Generation:
 Because the computer control used in the past is digital technology, the field instrument uses analog technology and has the following defects:
a) low speed and poor accuracy;
b) Too many cables and high costs;
c) There is no communication function between devices; 
d) Due to the different internal structure, different merchants have poor equipment interchangeability, which brings many problems to the user [4].
人员 The personnel in the field of self-control in various countries have explored for a long time and tried to disperse some of the control functions into the local instrumentation equipment so that the control functions are combined in the form of functional blocks. Interconnect the field instrumentation equipment with the host computer and realize two-way digital communication, and abide by a protocol specification. Therefore, the field bus emerged. 
4.1.2 Fieldbus Definition Fieldbus is an open, digital, multi-node communication technology that uses intelligent field devices and automation systems.
 4.1.3 Fieldbus types
Fieldbus includes FF (Fieldbus Foundation), DeviceNet, ProfiBus, HART (Highway Accessable Remote Transmitter), WorldFip, Interbus, CAN, and P-NET. About FF, DeviceNet and ProfiBus three field bus technical characteristics are compared in Table l.
4.1.4 Problems with the current fieldbus From the analysis of the three fieldbus interoperability testing techniques in Table 1, it is found that the fieldbus interoperability testing technology is still far from mature [5].
 It is difficult to achieve such a complex control system as the coordination of the machine stove by field bus technology.
 At present, fieldbus is not redundant, and fieldbuses are used in the reliability of power plant control.
 Because field bus is a new thing, there is no unified international standard. Some large international corporations, for their own commercial interests, did not allow each other to launch their own products and their own standards. This to a certain extent limits the promotion and use of fieldbus.
4.2 Power Plant Information Supervision System (SIS)
 Because of the emergence of SIS, DCS was further extended to the upper level, achieving all the process control, management, production, and management of the power plant.
SIS includes five functions:
a) Implement information management throughout the plant's production process (get information from DCS);
b) Real-time processing of plant-wide economic information and online cost calculations;
c) a cost-effective online processing system d) achieving economic load distribution among the units;
e) Operational assessment of economic operation of the unit and operation guidance for optimal operation.
At present, SIS is still in its initial application stage. Its system functions, management scope, etc. will conform to the development trend of the power market, and gradually sum up experience and gradually improve. However, in the future, when the plant and network are separated and the power market for competitive bidding is developed, the power companies will supplement the SIS content in the DCS, which will help the scientific management of the power companies and help establish a production management decision support system suitable for the power companies in China. .
 Some articles about the Supervisory Information System (SIS) refer to the "plant-wide monitoring and management system", and some refer to the "plant-wide management (monitoring) information system," "factory-level information management system," and "factory-level real-time information monitoring system." , "plant monitoring system" "factory monitoring information system" ... ..., to be unified as DCS named. The author thinks that Supervisory is an adjective. Translating Chinese into Chinese means "managing" or "supervising". There is no meaning controlled by Control, nor is it meant by Management Management. Therefore, it is translated into: the information monitoring system is more practical.
Fifth, on the relationship between DCS and FCS The distributed control system (DCS) generated by the bus (BUS) is to decentralize the instrument functions and centralize management. At present, the functions of DCS continue to expand, extending from DAS and MCS in the 1980s to now DEH, FSSS, SCS, BPS, ECS, FCS, and SIS. Due to the appearance of FCS and SIS and the subsequent access of NCS and TTS to DCS, DCS will be completely dispersed.
The emergence of fieldbus technology is an extension of DCS to the bottom layer. It is not consistent with the recent article about FCS replacing DCS. The meaning of FieldBus and distributed is different from the Chinese (English) meaning. . From a technical point of view, the FCS technology is to intelligently integrate field devices with CPU functions, change from analog communication to digital two-way communication in the field wiring, or leave the function dispersed, and concentrate on management. Some articles write that "in the future, analog-controlled DCS will be replaced by FCS." In fact, this sentence should be replaced by: In the future, the analog control of DCS will be replaced by the digital control of fieldbus technology; there is also no definition of DCS dispersion. The control system is analog control. Some professional and technical personnel affirmed in the article that "fieldbus is an extension of DCS control functions, improvement", "extension of fieldbus functions in existing DCS" and "DCS has not yet achieved true geographical dispersion in power plants" The application of fieldbus makes DCS completely disperse, etc., but at the same time, it also appears in the text that FCS will replace DCS in the future and whether it leaves a self-contradictory feeling.
Sixth, concluding remarks: Human progress, product development, this is an objective fact. Based on DCS of fieldbus technology and DCS of power plant information monitoring system and access to DCS through network control and remote control (remote control, telemetry, remote signaling), DCS will be completely dispersed. For the power design department, it is also necessary to coordinate the thermal control, electrical, and teleoperation specialties.
[references]
[1] An Yuxiang. Microcomputer control of industrial steam turbines [J]. Jilin Electric Power Technology, 1986 (1) 60 ~ 63.
[2] Li Zilian. Advancing with the times, pioneering and innovating - encourage and support the use of domestically distributed control systems (DCS) for 600MW units [N] China Instrument Telegraph, 2003.1.8
[3] An Yuxiang's design and operation of a coordinated control system for 200MW boilers [J]. Thermal Power Plant Automation, 1998(2) 36-40.
[4] Lin Deqiu. An Overview of Foundation Field Bus (FF)[J]. Electronic Quality, 2002(4) 31.
[5]Zheng Miao, Jia Yongle, Fieldbus Interoperability Testing Technology[J]. Electronic Quality, 2002(8)28.
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Due to the rapid development of electronic technology and the advent of microcomputers, there are more and more smart meters, as well as control from past electric unit instruments (DDZ-II, III) to assembly instruments (TF), programmable logic controllers (PLC), The microcomputer data acquisition system (DAS) has evolved into the distributed control system (Distributed Contol System, hereinafter referred to as DCS). At present, the DCS that implements the Fieldbus Contol System (FCS) DCS and the Supervisory Information System (SIS) is being studied.