Design Of Control System In Gas-Steam Combined Cycle Power Plants Based On Domestic XinHua DCS System

Distribute Control System(DCS) has been introduced into powe station control field in China market form the end of the 80's last century.Now it has been put into use widly,at the same time the domestic DCS has been developed adequately.But to gas-steam combined cycle it is full market for foreign DCS manufactures,which makes the project more investment.So in this thesis it introduces a newly control system-XDPS-400+,attributing to domenstic Xin Hua manufacture,which implement the unit and plant control of all of the gas-steam combined cycle power station through advanced and open network,remote I/O cabinets,reliable hardware and friendly man-machine interface. It can not only reduce the expense of the project,but also enhance the automation level of the project adopting to this newly control system which accumulates abundant experiences for the realization of supervising and controling plant system of gas-steam combined cycle power station and coal power station.First the development and the trend of indigenous DCS are overviewed to analyze the existing merits and defects of DCS and summarize itsapplica-tions in coal-fired power plant and put forward the feasibility of Xinhua sys-tem applied to CCPP Which have been approved successful in Suloge Gas turbine power plant and designed detail control project. In this paper desc-ribe the strategy of CCPP and amend existing problem.The gas-steam combined cycle power unit plant,which is a complex mul- tivariable controlled system with uncertainty,is composed of gas turbine,heat recovery steam generator(HRSG),steam turbine,generator,power networks, loads and such other equipment.Generally,we adopt to micro-computer system to control gas turbine and DCS has been used to control HRSG,steam turbine,generator and BOP system or common system.Both of the two system can collaborate to ensure unit with secure and economic operation Therefore,it is very difficult to accurately construct its mathematical model.For analogue control loop designed using typical PID control loop,the parameters are made up artificially in certain operating situations.When the situation changes,control performance will change for worse or even lead to abnormal operation of the unit.To this mat-ter,in this paper a optimization arithmetic-PSO based used to calculate analog control loop PID parameters to avoid the instability of unit because of mismatch the parameters in changing situation.Sulige CCPP unit 1 has been put into commercial operation from July 2006,in this period it has been in safe state.Practice proved that Xin Hua made a perfect control system for Sulige CCPP which met the unit control requirement,moreover add PSO into analog modulation loop which amend the shortcoming of routine PID control.The success of this project extends the percent of domestic market to Xinhua DCS,especially in CCPP.It has proved to be important strategy.