Research On Fault Ride Through And Stability Technology Of Large-Scale Wind Power DC Grid-Connected

With the large-scale development of globle wind power,increasing the capacity of renewable energy consumption has become a challenge for the world's energy development.VSC-HVDC technology is used to realize grid interconnection.It has the ability to quickly and independently adjust active power and reactive power.It has been widely used in new energy access,island power supply,and asynchronous interconnection.However,the harmonic stability and fault tolerance of large-scale wind power DC grid-connected have also received extensive attention,which has become a hot issue in current research.This paper mainly studies large-scale land-based doubly-fed wind power generation system and large-scale offshore direct-drive wind power generation system,and studies the fault ride-through capability and harmonic stability based on VSC-HVDC grid-connected system.Firstly,on the basis of literature research,this paper studies the high voltage ride through of DC grid-connected large-scale doubly-fed wind power generation system with weak research.In the case of large-scale doubly-fed wind farms undergoing symmetrical sudden rise faults at the grid-connected points under VSC-HVDC grid-connected,an effective control strategy aiming to restrain rotor over-current is proposed and the traditional control strategy of the rotor-side converter and grid-side converter is also improved,and a coordinated control protection scheme for wind turbines maintain its normal operation is given to improve its high voltage ride through capability.Then,an adaptive virtual resistance control strategy is proposed for VSC-HVDC grid-connected harmonic stability of large-scale offshore direct-drive wind power generation system.Based on the traditional control,the additional virtual resistance control strategy is improved and combined with the neural network,propose an adaptive harmonic control scheme suitable for neural networks.And provide a solution for the research of harmonic oscillation suppression for large-scale offshore wind power integration.Finally,the simulation model is built in PSCAD/EMTDC to verify the correctness of the theoretical analysis and the effectiveness and feasibility of the proposed control schemes.