Simulation Of Auxilary Power Control Using VRB Based Energy Storage System

With the increasing depletion of fossil energy, using new renewable energy generationhas become a trend. As the mature technology of renewable generation such as wind andphotovoltaic be developed rapidly and its randomness and volatility have become the mainrestricting factors of new energy large-scale power storage, the application of energystorage technology is considered to be an effective way to solve the problem. In many ofthe large-scale energy storage devices, vanadium redox flow battery(VRB) has the wideapplication prospect as a kind of green environmental protection of large capacity energystorage device, which becomes the research focus in the field of energy. This paperconcentrates on the application of auxilary power control using VRB based energy storagesystem, it is mainly devoted to the study of the following aspects.First of all, the advantages and disadvantages of the several common energy storagetechnology are compared in this paper. Combined with the application advantages of VRB,it analyzes its effective application feasibility as large-scale power energy storagecomponents in the future grid, and describes the research status of VRB based energystorage technology at home and abroad.Secondly, according to the simplified equivalent circuit of VRB, the detailed dynamicmathematical model of VRB is established based on PSCAD/EMTDC simulation platform.Through the two charge-discharge mode of constant power and constant voltage, the outputcharacteristic curves of VRB are obtained and the validity of the simulation model isverified in the simulation.Thirdly, based on PWM control of three-phase inverter, the detailed mathematicalmodel of energy storage battery unit with VRB is established. This paper adoptsdouble-loop feedback controller of power outside and current inner loop to implement P-Qdecoupled control of the energy storage unit, afterwards its output power has a fast trackwith the reference power signal.Finally, on the basis of primary frequency regulation in the traditional generator, thispaper puts forward f/P and V/Q control strategy to auxilary power control using VRB basedenergy storage system. By dynamic simulation method, the model of energy storage unit istested in a benchmark system including3conventional generators and9bus, under thecircumstances of load shedding and generator tripping, it shows that power control strategyof the energy storage unit auxiliary power grid is effective. These models are available inPSCAD/EMTDC, which can be used to accurately simulate the frequency regulation in anactual system.