Research On Excitation Control And Voltage Stability Of Dual-Axis Excitation Synchronous Condenser

With the increasingly prominent global energy crisis and environmental degradation issues,countries around the world are actively exploring generating electricity technology by new energy.Due to the uneven distribution of energy and load in China,the new energy power generation adopts the way of "centralized development and long-distance transmission".However,new energy generation is susceptible to system disturbances during high-voltage direct current transmission,which leads to an increased risk of chain off-network.Therefore,reactive power compensation devices need to be installed in new energy stations to increase reactive power reserve.In order to improve the voltage stability of the junction point of new energy,this thesis adopts a dual-axis excitation synchronous condenser,designs and optimizes the excitation system of the condenser,and studies the impact of the excitation mode on the voltage stability of the system.Firstly,this thesis analyzes the working principle of dual-axis excitation synchronous condenser and its excitation system,and establishes the corresponding mathematical model.Based on this,it derives the increment of reactive current of the dual-axis excitation synchronous condenser and takes the effective reactive current gain as the evaluation index of the reactive power characteristic.By analyzing the frequency domain sensitivity of the motor parameters under this index,it obtains the optimization direction of the motor parameters and selects the appropriate motor parameters.Secondly,this thesis uses the particle swarm algorithm to optimize the PID parameters of the dual-axis excitation synchronous condenser,so as to ensure the rationality of PID parameter values.Considering the time-varying and nonlinear characteristics of the excitation control parameters of the dual-axis excitation synchronous condenser in actual power system operation,it introduces fuzzy control to adjust the increment of PID parameters.At the same time,it uses wind power system model to conduct simulation experiments,which show that the optimized excitation system can improve the voltage stability of the system.Finally,this thesis analyzes the operating characteristics of dual-axis excitation synchronous condenser under normal excitation and single-axis excitation.Through the simulation experiment of wind power system,it proves that the dual-axis excitation synchronous condenser still has voltage regulation characteristics when the single-axis excitation system fails.Based on this,it studies the regulation effect of single-axis and dual-axis excitation on the voltage of the junction point under load disturbances and line faults.It finds that dual-axis excitation is more beneficial for improving voltage stability in power systems.