Analysis And Design Of Coordinated Control System Of2×350MW Supercritical Unit

Supercritical unit is the unit whose main export steam superheater pressure issupercritical parameters, compared with sub-critical units, supercritical units have thecharacteristic of high efficiency and economy. Supercritical unit has gradually developedinto the main units in our country at the present stage of the thermal power industry.Supercritical units is generally a once-through boiler，it is a typical three input threeoutput complex system of nonlinear，strong coupling, time-varying, multivariate andlarge delay. There is a cross-correlation between the different variables, so thecoordinated control system must be decoupled, compensation and variable parameterscontrol. The strategy of system must be boiler-turbine coordinated control. The loadcontrol of unit plant must coordinate the actions of both boiler and turbine. Under thecontrol process, it is not only necessary to coordinate actions on boiler and turbine, butalso take into account the stability of the unit and the internal external load changeoperating parameters.This paper has a discussion about the object of350MW supercritical once-throughboiler. First of all, it has a describe about the functions and tasks of supercritical controlsystems and the discuss about control method of coordinated control system, and thencombined with the practical experience, it has a detailed analysis of a power plantcoordination control strategy,this part mainly includes the load instruction loop、boilermaster control and the fuel control system and forced draft control system of boilersystem、turbine master control and feedwater control loop.Based on the real control parameter on debugging scene, established boiler andturbine control system simulation model, simulated the model by MATLAB software,and based on the simulation model, it had a analysis about system stability by changes inparameters of the controlled object and regulator parameters, on the basis of this, itdirected field debugging, improves the control level of the scene. At last, summarize theplant coordination control system parameter, it will have a great valve to the futurecontrol system.