Modeling And Optimization Of Coordinated Control System And Its Impact On Power Grid Stability

Power system has entered the era of large power grids and large unit, the unit control and coordination between unit and grid have become increasingly demanding. Modern thermal power generating units, especially in high-capacity, high parameter, the unit complexity is increasing. The difficulty in applying AGC to project lies in large lag and inertia for large capacity unit power, load respond is limited. The establishment of the accurate mathematical model of a unit effectively overcome the large lag and large inertia, then enhance the control quality of power plant control system.Bilinear fitting applied to the unit coordinated control system, complex binary function was fit as a bilinear structure that more accurate described the strong coupling relationship between the variables. the mathematical analysis was carried out by the regenerator system integrated into heat balance of generator unit. Under the physical concept of the global heat balance of drum-boiler turbine generator unit, a new type of simulation mathematical model for drum-boiler turbine generator unit with regenerator system was researched. Fussing multiple thinking modes of intelligent control, to research and design a generalized intelligent control system, which is fully described by state space method. The system steady sufficiency conditions and its stability proving are presented.With mathematical model of boiler-turbine coordinated control object, the concept of analogy flexible fuzzy control is introduced. And the algorithm has been proved by simulation test and practical process. This algorithm is easy to be realized in project by applying all sots of existing algorithms in computer system not depending of special fuzzy control module. Not only it, but also this algorithm can overcome the large lag and inertia for boiler and heightening the responding rate to AGC in boiler-turbine coordinated control system in effect and reheated temperature control characteristic.Based on non-linear mathematical model of unit, combined with bilinear fitting mathematical methods, analogy flexible fuzzy control concept and other intelligent control methods, power plant control system was improved and its quality control was enhanced. Then, the modeling features of control system for a large unit and its iMPact on modern power grid were studied. In order to study the long-term dynamic characteristic of generator in power system, it is presented a generalized speed governor model used in long-term dynamic simulation. The dynamic response characteristics of generalized speed governor model used in long-term dynamic simulation were analyzed. According to the characteristics of contemporary thermal power equipment, through the custom modeling method, and taking the unit mathematical model and its control systems into the simulation environment, primary frequency, boiler-turbine coordinated and power-frequency speed governor control mechanism are taken into simulation system to further explore the deep-seated reasons that caused the turbine pressure pulsation.