Application of DCS distributed control system in p

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The application of DCS in power plant

this paper focuses on the application of DCS in power plant, and describes the design ideas of main control functions in detail

1. Power generation system configuration

1.1 DCS constitutes the power plant control system. The whole plant is equipped with a set of distributed control system (DCS), which combines centralized operation with decentralized control of each section. The system adopts SIMATIC PCs, a German Siemens company, which can zoom in, zoom out and click the data corresponding to each point on the observation curve to meet its own needs and even the needs of the world. 7 the new control system is composed of an engineer station, five operation stations, a data archive station and five process processing centers. The control system communication has modern high-speed Ethernet (10/100lan), redundant communication equipment, and the total design i/o points include 2 production lines, steam turbine generators, medium and low voltage electrical systems and public systems, all of which have their own independent controllers. Each incineration line is installed with 7 remote i/o (input/output) stations, 1 steam turbine generator remote i/o (input/output) station, and 1 remote i/o (input/output) station to control the public system, The signals of medium and low voltage electrical equipment are processed separately. It realizes the production process status monitoring, operation, process control, event alarm, operation interlocking, safety protection, and completes the system functions of data acquisition (DAS), analog quantity control (MCS), sequence control (SCS) and interlock protection (pro)

1.2 i/o points of DCS

the total design i/o points of the system is 2303 points, and the actual capacity of the system is 3100 points. The number distribution of i/o points is as follows:

2. DCS control function

2.1 operator station

data acquisition and processing: regularly collect the input and output signals (including switching value, analog value and pulse value) of the production process of the whole station, filter them, detect out accidents, faults, status signals and analog signal parameter changes, update the database in real time, and provide the data of operation status for the monitoring system. Record the action of the automatic device according to the action sequence. Analog quantity sets several limits such as upper limit, upper limit, lower limit and lower limit. When the measured value exceeds the limit, an alarm will be sent. When an event occurs, start the relevant accident recall record, output the analog value before and after the accident, and the measuring point and period of the recall data can be defined

control operation: screen display and process display, control adjustment, trend display, hierarchical alarm management and real-time and historical display, report management and printing, operation record, operation status display, parameter configuration setting, operation authority protection and other functions. The locking function of safe operation is realized in the control

event alarm: alarm when an event occurs in the system or the operating equipment works abnormally

system self diagnosis: the self diagnosis of the monitoring system can test the width: 450mm, and the effective stretching stroke is 800mm; The fixture of the universal material testing machine moves at a uniform speed at the rate of 100 ± 20mm/min; The minimum length of the clamping surface of the universal material testing machine is 45mm in the direction of the force, and the pattern force is fixed mechanically or pneumatically. It can diagnose the communication channel, i/o module and other faults, alarm and record in the system self diagnosis table

system maintenance: system software self-monitoring system

the control system adopts the internationally popular upper computer monitoring mode, and the operation and monitoring of the whole control system are all realized on the upper computer. The upper computer can not only display the operation status, process parameters, alarms, etc. of the system equipment, but also display the power supply and communication status of PLC, bus module, etc. in the upper monitoring, and display the fault status of important i/o signals, which is convenient for troubleshooting. It can also select and switch various operation modes, and carry out automatic program control operation. At the same time, it also has analog parameter display, bar graph display, audible and visual alarm Print tabulation and other functions

2.2 engineer station

provide a set of desktop engineer stations for program development, system diagnosis, control system configuration, database and image and modification. The engineer station can call up any defined system display screen, and any display screen and trend chart generated on the engineer station can be loaded into the operator station through the data highway

the engineer station can call out the system configuration information and relevant data of any decentralized processing unit in the system through the data highway, and can also download the configuration data from the engineer station to each decentralized processing unit and operator station. In addition, when the reconfigured data is confirmed, the system can automatically refresh its memory

the engineer station includes station processor, graphics processor and main memory and external memory equipment that can accommodate all databases, various displays and system programs in the system. The historical trend buffer required for system trend display is also provided

the engineer station shall set the software protection password to prevent ordinary personnel from changing the control strategy, application program and system database without authorization

the engineer station also has the function of historical data station

the engineer station can support auxiliary devices such as CD recorders

the engineer station can perform performance calculation, file transmission, etc

2.3 Ethernet system

the system network is divided into lower level control and upper level management. The lower layer control adopts coaxial shield cable, which is suitable for European PROFIBUS standard. It is interconnected with asdp controller through im153-1 communication card on each et200m to meet the acquisition and processing of field signals and redundant communication of controller, which is PROFIBUS DP field communication. The upper management adopts coaxial cable, which is suitable for European PROFIBUS standard. Connect the OS station, ES station and cp443-5 communication card on the controller to meet the monitoring, control and management of field equipment by the operator station and engineer station, and realize data sharing. The other is the management Ethernet with coaxial thin cable and tcp/ip protocol, which is connected through the D-Link card on the OS station and ES station, and mainly realizes the file management between engineers and factory management

2. 4 process processing center

the model selection of process processing center is ash. The operation station uses CP1613 to connect with the redundant software package. In case of failure, the fault-tolerant communication will automatically continue. 1. Equipment name: Jinan experimental machine factory microcomputer controlled low-temperature full-automatic impact experimental machine line. The power supply is equipped with surge protection

plc system can operate continuously under high electrical noise, radio wave interference and vibration environment. All hardware in the programmable controller system can operate continuously and normally within the range of ambient temperature - 10 ~ 50 ℃ and relative humidity of 5 ~ 95%

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