Research On Coordinated Control System For Boiler-Turbine Units Guided By AGC Performance

With the large-scale application of wind and solar in power system, It is important for conventional thermal power units to participate in peak regulation for the safe operation of grid side. Two rules of grid for North China region that define the load regulation performance requirements of AGC units is proposed for the power quality. In order to overcome the effect caused by characteristics change of bolier-turbine under wide load variation and the power of units can meet load requirements of the grid side, this article research on the coordinaed control system design based on evolutionary algorithm optimization.The thesis includes the following aspects:1. On the basis of unit non-linear model analysis, the quantitative relationship between the unit nonlinearity and coordinated control system robustness index is determined. A scientific method to decide typical operating points is proposed, the linearized model of boiler-turbine unit is obtained at typical operating points, the nonlinear measure based on gap distance is applied to analyze nonlinearity of the system, calculation the gap distance between two linearized models.2. It is introduced the coordinated control system which local controllers is based on the single-objective evolutionary algorithm and gain schedule control is apply to realize global controller. The design of coordinated control system is attributed to the multi-objective optimization problem which take regulation performance of load and main steam pressure as optimization objectives, robustness and maximum deviation of main steam pressure as constrains, convert it into a single objective optimization problem, application two kinds of evolutionary algorithms to design local controllers, analysis and comparison the robustness, load and main steam pressure regulation performance of different local controllers, verification the performance of the global controller under wide load variation.3. It is proposed the coordinated control system based on multi-objective evolutionary algorithm based on optimization units AGC performance. The optimization model of coordinated control system is improved by taking AGC performance as a part of optimization objectives, analysis characteristics of many kinds of multi-objective evolutionary algorithms, determination the multi-objective evolutionary algorithm to slove multi-objective optimization problem of coordinated control system, making improvement of this algorithm on three aspects, simulation results show that the proposed coordinated control system has good AGC regulation performance and robustness and the algorithm is effective.4. It is proposed a supercritical unit coordinated control system design method fot the practicality and optimization of global performance. Analysis characteristic and control feature of the supercritical unit, it is summarized two typical coordinated control system engineering design ideas for supercritical unit. It is proposed a control scheme that static decouple and multi-variable PI are included for the coordinated control system, and gain schedule control is applied to realize the consistency of global performance. Simulation results show that the proposed coordinated control system is effective.