| The feature and the control performance of direct air cooling system has been analyzed in this paper. Using the OPC (for process control of the Object Linking and Embedding) technology and the DCS (Distributed Control System), the field data is import into MATALB for processing and analysis. Under the direction of theory of identification, modeling, simulation, optimization and fault diagnosis, the air-cooling system parameter optimization and the fault diagnosis have completed. The main research contents are as follows:1,The characteristics of air-cooling system and the development process of domestic and international trends in research and development of integrated thermal power units have been presented. And the main contents and approaches in the research of direct air cooling system is introduced in the paper.2,The application of DCS in direct air cooling system control is discussed in this paper. Considering the performance characteristics of the DCS, the DAQ scheme for direct air cooling system using Guodian Zhishen ver. EDPF-NT DCS is proposed in view of the characteristic about large-scale, multi-parameter, complex of equipment convergence and vulnerability to natural climate impact of "air cooling island". The data acquisition programme of air cooled condenser temperature and pressure, the programme of large-sized axial fan frequency control and the programme of communication or connection between air cooling system DCS and electric control system(ECS) are included in this scheme. Variable data acquisition program and hardware configuration, data access, database, as well as the definition and operation of control system configuration using EDPF-NT system has accomplished. The "air-cooled Island" control system design is completed initially in the section.3,The operating characteristics and the data organization of DCS has been analyzed. And the OPC technology has been chosen for data communication between DCS and external software after comparing several industry communication technology. The approach which realize the communication between MATLAB and EDPF-NT system using OPC ActiveX technology has been given, and has been successfully applied in communication between EDPF-NT DCS and air cooling system optimization soft packet. 4,The direct torque control technology is applied to the fan speed control in variable frequency in accordance with the technical characteristics of axial flow fan in direct air-cooling system. Combination of low-speed running performance requirements in axial flow fan, the flux models and start-up mode has been used to improve the low-speed performance of axial flow fan. The list of inverter switches choice has been given, and the control algorithm of the inverter is completed. The simulation study proved that the design of direct torque control system is feasible.5,The field DCS data is read and imported into MATALB optimization platform, then the algorithm of system identification, parameter optimization and fault diagnosis have studied, mathematical models of the object to be controlled have been set up. Through application of genetic algorithms and other algorithm, the PID controller parameters have been optimized. So the PID parameter in DCS is advised. Multiblock PCA has also been applied in fault diagnosis of air cooling system and an application instance has been given.6,Air cooling system optimization soft packet has been developed on the MATLAB platform. And the communication between the soft packet and ver. EDPF-NT DCS, Likong configuration software, and other configuration software is achieved at the support of OPC technical. Accordingly, the air cooling system optimization platform including PC, DCS , configuration software, optimization software package is integrated. |
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