Study Of The Dynamic Model Of Nuclear Power Plant And Coordinated Optimization Of Grid-related Protection

At present, China's nuclear power development very quickly. Nuclear power has features including One-mega kilowatt of unit capacity, high requirement of nuclear safety, low operating costs and so on. Its power output characteristics and frequency regulation characteristics are different from conventional hydraulic power plants and thermal power plants. Besides, nuclear power plant and its auxiliary equipment are sensitive to disturbance of power grid frequency and voltage. When the nuclear power plant is connected to the grid, a sudden load rejection or cutting machine will result in the loss of a large active power source to the power system, thus may have a serious impact on power grid's stability. Therefore, the establishment of large-scale PWR nuclear power plant dynamic models and the study of nuclear power plant operating characteristics have theoretical and practical significance.The dissertation reviewed a large number of domestic and foreign literatures, and combined a number of scientific research projects. The large-scale PWR nuclear power plant dynamic models and machine network coordination issues were studied deeply and systematically. The main contents are as follows:The components and characteristics of the large pressurized water reactor (PWR) nuclear power plant (NPP) were reviewed and analyzed in this dissertation. The reactor core and thermal system model were built for AP1000, in which reactor core, coolant system model, steam system model were included. The self-stability characteristics of reactor core and thermal system was deduced and analyzed based on shifted-ectropy. A modified IETLBO algorithm was proposed to identify parameters of reactor core and power regulation system model. The effectiveness of the algorithm was verified and it had better performances in precision speed and robustness. Besides, IETLBO depended least on algorithm parameters.Based on PSASP/UPI, the large pressurized water reactor (PWR) nuclear power plant dynamic model was built. The characteristics of reactor core and thermal system model, excitation speed system model, related protection system model had been considered in this model. Compared with PCTRAN, the effectiveness of the proposed model was verified. Based on the nuclear power plant dynamic model, the power regulation characteristics of nuclear power plant was analyzed.Based on the established dynamic model of the large-scale pressurized water reactor nuclear power plant, the characteristic of primary frequency regulation was simulated and analyzed in actual power system example. And the effect of the nuclear power plant on the stability to power system was evaluated based on the transient energy function analysis method. The parameters optimization scheme was put forward too. The overspeed protection and super acceleration protection features of nuclear power plant had been simulated, and the effectiveness of the established model of overspeed protection and super acceleration protection verified by the simulation results. The coordinated strategy of overspeed protection and super acceleration protection is put forward.The excitation-loss protection model of nuclear power plant was established. The excitation-loss characteristics and mechanism of nuclear power plant under different power levels were simulated and analyzied based on the established dynamic model for the large-scale pressurized water reactor nuclear power plant. The results showed that nuclear power plant on full load loss has great impact on magnetic core and the thermal system and the protection system should be tripped reliably. And it had limited impact on nuclear core and thermal system with50%FP load, the nuclear power plant could be operated asynchronously in short term to reduce the impact of nuclear power plant trip on the grid. The super acceleration protection would lead to overspeed of the unit with50%FP load when loss of excitation happened. The simulation result also indicate that setting dead zone of frequency of super acceleration protection could prevent overspeed of the unit.