Modeling On Power System Of Thermal Power Unit And Its Application In Power System Stability Analysis

Thermal power has been to dominate through the supply of electricity in the power system, and the research on operational characteristics of thermal power plant has become an important part of power analysis.However, the focus of existing system simulation software is usually transient process, there generally does not have a complete turbine, boiler and its control system. But the power system stability problems is getting more complicated with the expansion of the scale of interconnected power grid and a new range of dynamic elements linked to grid, and the stability damage of cross regional interconnected power grid shows more mid-term and long-term dynamic instability process. Then the existing of slow dynamic makes mid-term and long-term instability of system to happen. To address the above problems, the main contributions done by this paper include as follows:Fistly, mathematical model of thermal power unit is modeled in the article. The thermal power unit is a multivariable system with the characteristic of non-linear and slowly time varying parameter and hysteresis and big inertia In order to describe the dynamic characteristics in variable working conditions of thermal power unit, the non-linear mathematical model of thermal power unit is modeled, which combined the method of system identification with the main process parameters of a controlled object of coordinated control system for supercritical unit, and the rationality of the model is verified by the method of mathematical analysis. Mathematical model with reheat system for thermal power unit is modeled based on the characteristic of modern large thermal power unit, and the dynamic characteristics between power unit with reheat system and power unit without reheat system is studied through simulation. The coordinated control system with increment function observer is designed based on characteristic of controlled object of coordinated control system for thermal power unit, and the control system can guarantee the whole controlled object asymptotic stability, and the decoupled control about control system between turbine valve and fuel flow can be achieved.Secondly, the correctness and reasonableness of the mathematical model of power system for thermal power unit modeled in the articleis is verified in the process of electromechanical transient and mid-term and long-term dynamic simulation, the simulation results show that the model can completely reflect the dynamic characteristics of thermal power unit. The regulation of the model to power system in which the model is applied a regional power grid.Finally, configuration framework and information process of full-process dynamic simulation system with parallel-in-time-space is proposed in the article. The stability problem of modern power system is becoming increasingly complex, and it is difficult to strictly distinguish electromagnetic and electromechanical etc, and it is more likely an associated process.