To mitigate the impact of wind power volatility on power system scheduling,this paper adopts the wind-storage combined unit to improve the dispatchability of wind energy.And a three-level optimal scheduling and power ...To mitigate the impact of wind power volatility on power system scheduling,this paper adopts the wind-storage combined unit to improve the dispatchability of wind energy.And a three-level optimal scheduling and power allocation strategy is proposed for the system containing the wind-storage combined unit.The strategy takes smoothing power output as themain objectives.The first level is the wind-storage joint scheduling,and the second and third levels carry out the unit combination optimization of thermal power and the power allocation of wind power cluster(WPC),respectively,according to the scheduling power of WPC and ESS obtained from the first level.This can ensure the stability,economy and environmental friendliness of the whole power system.Based on the roles of peak shaving-valley filling and fluctuation smoothing of the energy storage system(ESS),this paper decides the charging and discharging intervals of ESS,so that the energy storage and wind power output can be further coordinated.Considering the prediction error and the output uncertainty of wind power,the planned scheduling output of wind farms(WFs)is first optimized on a long timescale,and then the rolling correction optimization of the scheduling output of WFs is carried out on a short timescale.Finally,the effectiveness of the proposed optimal scheduling and power allocation strategy is verified through case analysis.展开更多
To ensure frequency stability in power systems with high wind penetration,the doubly-fed induction generator(DFIG)is often used with the frequency fast response control(FFRC)to participate in frequency response.Howeve...To ensure frequency stability in power systems with high wind penetration,the doubly-fed induction generator(DFIG)is often used with the frequency fast response control(FFRC)to participate in frequency response.However,a certain output power suppression amount(OPSA)is generated during frequency support,resulting in the frequency modulation(FM)capability of DFIG not being fully utilised,and the system’s unbalanced power will be increased during speed recovery,resulting in a second frequency drop(SFD)in the system.Firstly,the frequency response characteristics of the power system with DFIG containing FFRC are analysed.Then,based on the analysis of the generation mechanism of OPSA and SFD,a combined wind-storage FM control strategy is proposed to improve the system’s frequency response characteristics.This strategy reduces the effect of OPSA and improves the FM capability of DFIG by designing the fuzzy logic of the coefficients of FFRC according to the system frequency index in the frequency support stage.During the speed recovery stage,the energy storage(ES)active power reference value is calculated according to the change of DFIG rotor speed,and the ES output power is dynamically adjusted to reduce the SFD.Finally,taking the IEEE 39-bus test system as an example,real-time digital simulation verification was conducted based on the RTLAB OP5707 simulation platform.The simulation results showthat theproposedmethodcan improve theFMcapabilityofDFIG,reduce the SFDunder thepremise of guaranteeing the rapid rotor speed recovery,and avoid the overshooting phenomenon so that the systemfrequency can be quickly restored to a stable state.展开更多
Energy storage can further reduce carbon emission when integrated into the renewable generation.The integrated system can produce additional revenue compared with wind-only generation.The challenge is how much the opt...Energy storage can further reduce carbon emission when integrated into the renewable generation.The integrated system can produce additional revenue compared with wind-only generation.The challenge is how much the optimal capacity of energy storage system should be installed for a renewable generation.Electricity price arbitrage was considered as an effective way to generate benefits when connecting to wind generation and grid.This wind-storage coupled system can make benefits through a time-of-use(TOU)tariff.A proportion of electricity is stored from the wind power system at off-peak time(low price),and released to the customer at peak time(high price).Thus,extra benefits are added to the wind-storage system compared with wind-only system.A Particle Swarm Optimization(PSO)algorithm based optimization model was constructed for this integrated system including constraints of state-of-charge(SOC),maximum storage and release powers etc.The proposed optimization model was to obtain the optimal capacity of energy storage system and its operation control strategy of the storage-release processes,to maximize the revenue of the coupled system considering the arbitrage.Furthermore,the energy storage can provide reserve ancillary services for the grid,which generates benefits.The benefits of energy storage system through reserve ancillary services were also calculated.A case study was analyzed with respect to yearly wind generation and electricity price profiles.The benefit compared with no energy storage scenario was calculated.The impact of the energy storage efficiency,cost and lifetime was considered.The sensitivity and optimization capacity under various conditions were calculated.An optimization capacity of energy storage system to a certain wind farm was presented,which was a significant value for the development of energy storage system to integrate into a wind farm.展开更多
基金supported by the State Grid Jiangsu Electric Power Co.,Ltd.Technology Project(J2023035).
文摘To mitigate the impact of wind power volatility on power system scheduling,this paper adopts the wind-storage combined unit to improve the dispatchability of wind energy.And a three-level optimal scheduling and power allocation strategy is proposed for the system containing the wind-storage combined unit.The strategy takes smoothing power output as themain objectives.The first level is the wind-storage joint scheduling,and the second and third levels carry out the unit combination optimization of thermal power and the power allocation of wind power cluster(WPC),respectively,according to the scheduling power of WPC and ESS obtained from the first level.This can ensure the stability,economy and environmental friendliness of the whole power system.Based on the roles of peak shaving-valley filling and fluctuation smoothing of the energy storage system(ESS),this paper decides the charging and discharging intervals of ESS,so that the energy storage and wind power output can be further coordinated.Considering the prediction error and the output uncertainty of wind power,the planned scheduling output of wind farms(WFs)is first optimized on a long timescale,and then the rolling correction optimization of the scheduling output of WFs is carried out on a short timescale.Finally,the effectiveness of the proposed optimal scheduling and power allocation strategy is verified through case analysis.
基金funded by Jilin Province Science and Technology Development Plan Projects(20230508157RC)the National Natural Science Foundation of China(U2066208).
文摘To ensure frequency stability in power systems with high wind penetration,the doubly-fed induction generator(DFIG)is often used with the frequency fast response control(FFRC)to participate in frequency response.However,a certain output power suppression amount(OPSA)is generated during frequency support,resulting in the frequency modulation(FM)capability of DFIG not being fully utilised,and the system’s unbalanced power will be increased during speed recovery,resulting in a second frequency drop(SFD)in the system.Firstly,the frequency response characteristics of the power system with DFIG containing FFRC are analysed.Then,based on the analysis of the generation mechanism of OPSA and SFD,a combined wind-storage FM control strategy is proposed to improve the system’s frequency response characteristics.This strategy reduces the effect of OPSA and improves the FM capability of DFIG by designing the fuzzy logic of the coefficients of FFRC according to the system frequency index in the frequency support stage.During the speed recovery stage,the energy storage(ES)active power reference value is calculated according to the change of DFIG rotor speed,and the ES output power is dynamically adjusted to reduce the SFD.Finally,taking the IEEE 39-bus test system as an example,real-time digital simulation verification was conducted based on the RTLAB OP5707 simulation platform.The simulation results showthat theproposedmethodcan improve theFMcapabilityofDFIG,reduce the SFDunder thepremise of guaranteeing the rapid rotor speed recovery,and avoid the overshooting phenomenon so that the systemfrequency can be quickly restored to a stable state.
基金Beijing Natural Science Foundation[JQ21010]National Science Fund for Distinguished Young Scholars[51925604]+1 种基金Science and Technology Program of Inner Mongolia Autonomous Region(2021ZD0030)Xplorer Prize.
文摘Energy storage can further reduce carbon emission when integrated into the renewable generation.The integrated system can produce additional revenue compared with wind-only generation.The challenge is how much the optimal capacity of energy storage system should be installed for a renewable generation.Electricity price arbitrage was considered as an effective way to generate benefits when connecting to wind generation and grid.This wind-storage coupled system can make benefits through a time-of-use(TOU)tariff.A proportion of electricity is stored from the wind power system at off-peak time(low price),and released to the customer at peak time(high price).Thus,extra benefits are added to the wind-storage system compared with wind-only system.A Particle Swarm Optimization(PSO)algorithm based optimization model was constructed for this integrated system including constraints of state-of-charge(SOC),maximum storage and release powers etc.The proposed optimization model was to obtain the optimal capacity of energy storage system and its operation control strategy of the storage-release processes,to maximize the revenue of the coupled system considering the arbitrage.Furthermore,the energy storage can provide reserve ancillary services for the grid,which generates benefits.The benefits of energy storage system through reserve ancillary services were also calculated.A case study was analyzed with respect to yearly wind generation and electricity price profiles.The benefit compared with no energy storage scenario was calculated.The impact of the energy storage efficiency,cost and lifetime was considered.The sensitivity and optimization capacity under various conditions were calculated.An optimization capacity of energy storage system to a certain wind farm was presented,which was a significant value for the development of energy storage system to integrate into a wind farm.
