Research On Regulation Strategy Of Storage-based Wind Farm After Black-start Of Thermal Power Unit

Hydroelectric plant(Pumped storage power station contained)is the best choice for black-start power source,but because of the restriction of regional source,water source is shortage in Inner Mongolia and northwest China.Once blackouts occurs,the recovery of power grid would depend on the major grid,which would cost a longer time.Wind resource is rich in these area and wind power becomes the major generation type.if storage-based wind farm is used as the black-start power source of local grid,it would add the capacity of black-start power source and enhance the fault recovery speed.After the black-start of thermal power unit,the primary goal of the local power grid should be restart more thermal power unit.But the thermal power unit would easily collapsed in the restoration of other units,leading to the failure of grid black-start.After the success of the black-start of the thermal power unit,storage-based wind farm and the thermal power unit run side by side,storage-based wind farm fast power adjustment capability can more effectively improve the local area network recovery speed and reliability.In order to form wind-battery-thermal unit hybrid network and make it be able to maintain stability in local area network recovery,so a deep research on regulation strategy of storage-based wind farm is made in this paper:(1)Simulation model of DFIG and BESS is established.the mathematical model of Doubly Fed Induction Generator(DFIG)in grid-connected condition is established by analyzing the operation principle;simulation model of battery energy storage system(BESS)is established.(2)BESS control unit control strategy smooth switching method is designed.The operation mode of BESS in storage-based wind farm and wind-battery-thermal unit hybrid network is expounded,Designed smooth switching control strategy to achieve its control strategy switched by V/f to P/Q when hybrid network is formed;The simulation results show that hybrid network enter the stable operation state in a short period of time.(3)The control strategy to improve the inertia and damping characteristics of hybrid network is studied.The power characteristics of DFIG is studied,and the causes of the low frequency oscillation is analyzed.The control strategy of storage-based wind farm in different operation of black-start is designed.Finally,the validity of the proposed control strategy is verified by simulation.By research in this paper,with the regulation strategy of storage-based wind farmthis paper presents,BESS control strategy switches by V/f to P/Q smoothly in parallel operation of thermal power unit and storage-based wind farm,and improve voltage and frequency stability of hybrid network effectively.