Research On Modeling And Parameter Optimization Of Hydropower Unit

China’s power system has developed rapidly in the past 30 years,whether the voltage level and the scale of the grid,or the total installed capacity of hydropower units and the total power generation is at the forefront of the world.Along with these achievements,the problem of safety and stable operation of power grid has been put forward,which demands a better performance of the power equipment’s controller.Hydropower unit undertakes important task such as responding quickly to load demand,adjusting frequency and phase,emergency reserve,thus it becomes a reliable barrier for the secure and stable operation of power grid.Therefore,it is of great engineering value to improve the operation stability of hydropower units and providing the governor with a better regulation quality.Hydraulic turbine and water diversion pipe system,generator and load system and controller system were analyzed and established based on the physical structure of hydropower unit at first.The stand-alone operation and double machine parallel operation simulation model were built on the MATLAB/SIMULINK simulation platform.According to the research of hydraulic turbine governor PID robust optimization parameters,fitness function was designed considering the ITAE index,sensitivity and complementary sensitivity index of the system in the next place,and the comprehensive fitness function was solved by using Particle Swarm Optimization.The simulation results show that compared with the PID parameters obtained by using the ITAE performance index,the PID parameters obtained by the robust optimization method can greatly improve the robustness and performance the governor of hydropower units under the condition of changing output power.A hydropower plant which operated with isolated load was selected as the research object in the end of this paper,the low frequency oscillation of the system was successfully simulated by using the double machine parallel operation simulation model,and the influence of the Ef and bp were analyzed based on the simulation model,then the PID parameters of frequency regulating unit were optimized by using the robust optimization method.The investigation of this paper shows that the parameters of the speed regulation system of the unit should be rationally allocated according to the task of the unit: for the No.1 hydropower unit which adjusts the frequency of the system,the PID parameters must be optimized,the value of Ef can be small or set to zero,and the value of bp should be 0.01;While for the No.2 hydropower unit which bears base load,the PID parameters of large grid can be used,and a large value of Ef is need,besides the value of bp cannot be smaller than 0.04.The conclusion has been verified by the experiment of the PSD-BPA simulation software in the end.