| With the emergence of regional interconnection of the power system and the increasing penetration rate of wind power generation,the scale of the power system has become larger and larger,and the structure has become increasingly complex.Its operation is affected by more factors than before.When the system is insufficiently damped Small disturbances cause low-frequency oscillations,dangerous to the safe operation of the power system.Therefore,improving the damping characteristics and improving the stability of the power system are important tasks to be solved urgently.This article introduces the basic trend of wind power generation in the current power system,as well as the oscillation problem caused by the low damping of the system under the background of power system interconnection.The problem of DFIG and SVG additional damping control to suppress oscillations has been studied in depth,and the additional damping controller parameters have been optimized based on PSO.First of all,this article establishes a mathematical model of low-frequency oscillations of the power system,and theoretically explains the relevant factors that affect system damping;establishes a DFIG mathematical model,including aerodynamic models,transmission mechanism models and converter models,and introduces DFIG operation control strategies;Establish a mathematical model of SVG and carry out the control system of SVG.Secondly,analyze the principle of dynamic active and reactive power enhancement system damping,establish an additional damping controller model,design additional damping controller based on DFIG and SVG structure;for DFIG power plants with static reactive power generators,a DFIG is proposed The method of unit cooperation with SVG grid connection adopts the control strategy of additional damping,accesses the power control node of the control system,changes the active and reactive reference currents of the reference device,realizes the dynamic output power of the device,offsets the power increase,and generates The power oscillation is suppressed.Build a control system model of a 4-machine 2-area system in which DFIG and SVG are connected to the grid in Simulink,add additional damping control signals,control the active power output by DFIG and the reactive power output by SVG,change the characteristic root of the system,and based on the Prony method Analyze each mode of the oscillation signal.Finally,an overview of the optimization algorithm is introduced,and the program design and step realization of the parameter optimization method of the additional damping controller based on the PSO algorithm are described.The parameters of the additional damping controller of the SVG are integrated and optimized,and the programming is completed in Matlab/Simulink.A simulation model was built,and the simulation results proved the feasibility and good optimization effect of the PSO-based SVG additional damping controller parameter optimization method. |
