Research On The Unit Coordinated Control Of Thermal Power Plants

With the continuous commissioning of high-capacity and high-parameter units of thermal power plants, and large-scale construction of wind farms and solar farms, the current grid pattern have great influence, especially for small and medium-sized thermal power plants. Those are involved higher and higher demands over the load regulation capacity of the power grid. Therefore, it is a critical issue to improve the coordination control method for the thermal power plant unit to meet the power load demand and the safe operation of a thermal power plant unit.Since the coordination control of thermal power plant units is a multi-variable controlled object with non-linear, parameters’ time-varying and long-delay characteristics, conventional boiler-turbine coordination control approach cannot always meet the demands of power grids over unit’s coordination and control system.Based on proportion integration control method widely used in the power unit control system, the actual operating conditions and control problem of350MW unit in Fuxin Power Plant were researched. Considering the limitations of coordination control, the optimal control approach and decoupling control approach have been proposed. Theoretical analysis and running test show that the optimized control method significantly improves the load response rate and ensures the quality of the system, with better effects in practical applications. At the same time, the robustness of control system was also studied. The results demonstrate that the proposed method have better effectiveness in both large load and low load condition. Furthermore, a new neural network based proportion integration control approach was proposed and the stability can be guaranteed by theoretical proof. This kind of approach deal with the effect of input output of systems coupling in unit. And it also makes the output of system stable and improves the control performance.At last, the adverse effects of coal on unit coordination and control system have been analyzed and correspondingly improved method was proposed in the control system. By improving some control condition, the load ability for the unit coordination control system to adapt to changing coal capacity has been further enhanced with higher economical efficiency, and satisfies the needs of the power load.