Research On Virtual Synchronous Generator Technology And System Stability Control Strategy

With the rapid growth in HVDC project as well as the traditional synchronous generator installed proportion reduced,will present the trend of the power electronic power system,reduce grid inertia,damping,the ability to resist disturbance.The grid-connected power electronic device has the operation characteristic of similar synchronous generator,which can realize the friendly access of the converter device and improve the stability of the power system.Paper to VSC-HVDC inverter station as the research object,focuses on virtual synchronous generator parameters Settings,mainly from the modeling,virtual synchronous generator inertial time constant and damping coefficient of the influence of the small signal stability of ontology and its access system to the system small signal stability and transient stability such aspects as the influence of the concrete research,the main research content is as follows:(1)the virtual synchronous generator model of vsc-hvdc inverter station was established.The simulation verifies that the dynamic response of reactive power and reactive power is oscillating in the converter station,and verifies the feasibility of the control scheme of the virtual synchronous generator.(2)the cooperative adaptive adjustment strategy of the rotational inertia and damping coefficient of the virtual synchronous generator is proposed.Using virtual synchronous generator inertia and damping coefficient of both the advantages of flexible adjustment,put forward a multi-parameter coordinated adaptive adjustment strategy,the simulation experiment in the MATLAB/Simulink software,active power and angular velocity the minimum amount of overshoot,proves that the proposed multi-parameter coordinated adaptive control strategy is effective,verify the effectiveness of the proposed control strategy.(3)the influence of virtual inertia time constant on the small disturbance and stability of the network is analyzed.Firstly,the analytic expression of low frequency oscillation attenuation factor is obtained by linearizing the network equivalent system.Then analyzed the inertial time constant under different scenarios for the influence degree of the small signal stability level,and finally in classical model and four machine for example simulation conclusion,the parameter setting and interconnected system for the study of virtual synchronous generator area oscillation stability analysis and control has a certain reference value.(4)the key parameter setting problem of virtual synchronous generator considering multiple targets is studied.The small signal stability and the small interference stable multi-objective optimization model of the virtual synchronous generator system are established.Based on non dominated sorting and crowded distance multi-objective particle swarm optimization(pso)algorithm and the entropy weight of the compound fuzzy matter-element method of multi-objective optimization method,in two machine system simulation to verify the proposed optimization model and algorithm for virtual synchronous generator parameters setting and the regional oscillation stability analysis and control of the interconnected system has a certain reference value.(5)the influence of virtual inertia time constant on transient stability of interconnected power grid is analyzed.Based on transient energy function method,makes use of virtual synchronous generator system inertial time constant variable and adjustable features,respectively,the single machine infinite system are studied and the equivalent inertia time constant of interconnected power grid in two machine system transient stability,the influence of the last four machine in two classic verified the conclusions in the model,parameter setting and research for virtual synchronous generator interconnected system transient stability analysis and control has a certain reference value.