Research On The Power Of Wind Farm Based On Multilevel STATCOM/BESS Coordinated Control

Wind power generation technology is dominant in the field of new energy power generation.Because of the wind's itself inherent randomness and uncertainty,large wind farms parallel have an undeniable effect on the safe operation of power grid and FM.In order to ensure the quality of wind power grid electricity,using STATCOM is a way to compensate wind farms with reactive power and to stabilize node voltage;Use of energy storage device to tame for wind power active power fluctuations caused by randomness and volatility,to stabilize the system frequency.STATCOM/BESS combines the advantage of the two above,save the cost of investment,and has the advantage of the active reactive power compensation at the same time,which has four quadrant power adjustment ability and provide more flexible functions of power quality regulation.To sum up,this paper studies the chain multilevel STATCOM/BESS device,mainly did the following work.Firstly,chain topology of multilevel STATCOM and the working principles of STATCOM with energy storage system were studied,and analyzed the advantages of combination of STATCOM device and battery to compensate the power of wind field.Through the establishment of simplified multilevel H bridge model to study the chain mathematical model of multilevel inverter.Analyzed the control strategy of the voltage,current double closed-loop decoupling and researched the reasons of dc side voltage unbalance,then adopted hierarchical control of voltage outer ring to balance the dc side voltage and using the dc side voltage to control the modulation of H Bridge,Furthermore,established the mathematical model of the energy storage system,and designed the related parameters of battery capacity as well as STATCOM/BESS device through actual examples.Secondly studied the use of DC active filter(DC-APF)inhibiting H bridge DC chain ripple current low frequency and high frequency current component(two times),the method of analysis,the mechanism of the ripple current ripple current H bridge circuit model was established,and ripple current transport was studied too.For DC-APF topology has carried on the detailed study,and put forward the corresponding control strategy,and has made the analysis parameters of the filter.Set up the simulation in MATLAB/Simulink software platform,the DC-key performance of active power filter APF was validated.And then studied the power coordinated control method of the chain multilevel STATCOM/BESS device which is power coordinated control strategy based on nuclear power battery state of(SOC).The controlling parameter of that is to ensure the device's compensating reactive current reference by active power fluctuation and its control principle and node voltage size in order to realize dynamic compensation of wind power fluctuations,which can not only stabilizes node voltage with wind power fluctuations,but also avoids the phenomenon of battery overcharge and discharge.Based on battery power coordinated control strategy of SOC algorithm detailed research,based on the grid allows the grid voltage and frequency fluctuations within a certain range,the threshold setting compensation control algorithm to avoid frequent battery discharge.Finally using MATLAB/Simulink simulation software to set up three H bridge cascade multilevel STATCOM seven/BESS system simulation model of grid-connected wind farms verifying two situations,one is priority compensation of active power under the condition of wind speed fluctuations,the other is priority compensation of reactive power under node voltage disturbance which proved the compensation effect of STATCOM/BESS.Through the analysis of simulation results,proved that the DC/APF can effectively reduce the ripple current of battery and increase the use efficiency of the battery.when wind farms and node voltage or frequency disturbance occurs,the simulation results show that under the premise of no happening of overcharging and discharging,STATCOM/BESS can go on preferentially active and reactive power dynamic compensation according to the state of networks,which improving the compensation efficiency of the device.Therefore,the study of the coordinated control strategy based on the wind power is feasible.