As renewable energy continues to be integrated into the grid,energy storage has become a vital technique supporting power system development.To effectively promote the efficiency and economics of energy storage,centra...As renewable energy continues to be integrated into the grid,energy storage has become a vital technique supporting power system development.To effectively promote the efficiency and economics of energy storage,centralized shared energy storage(SES)station with multiple energy storage batteries is developed to enable energy trading among a group of entities.In this paper,we propose the optimal operation with dynamic partitioning strategy for the centralized SES station,considering the day-ahead demands of large-scale renewable energy power plants.We implement a multi-entity cooperative optimization operation model based on Nash bargaining theory.This model is decomposed into two subproblems:the operation profit maximization problem with energy trading and the leasing payment bargaining problem.The distributed alternating direction multiplier method(ADMM)is employed to address the subproblems separately.Simulations reveal that the optimal operation with a dynamic partitioning strategy improves the tracking of planned output of renewable energy entities,enhances the actual utilization rate of energy storage,and increases the profits of each participating entity.The results confirm the practicality and effectiveness of the strategy.展开更多
The time-of-use(TOU)strategy can effectively improve the energy consumption mode of customers,reduce the peak-valley difference of load curve,and optimize the allocation of energy resources.This study presents an Opti...The time-of-use(TOU)strategy can effectively improve the energy consumption mode of customers,reduce the peak-valley difference of load curve,and optimize the allocation of energy resources.This study presents an Optimal guidance mechanism of the flexible load based on strategies of direct load control and time-of-use.First,this study proposes a period partitioning model,which is based on a moving boundary technique with constraint factors,and the Dunn Validity Index(DVI)is used as the objective to solve the period partitioning.Second,a control strategy for the curtailable flexible load is investigated,and a TOU strategy is utilized for further modifying load curve.Third,a price demand response strategy for adjusting transferable load is proposed in this paper.Finally,through the case study analysis of typical daily flexible load curve,the efficiency and correctness of the proposed method and model are validated and proved.展开更多
Desert phreatophytes are greatly dependent on groundwater, but how their root systems adapt to different groundwater depths is poorly understood. In the present study, shoot and root growths of Alhagi sparsifolia Shap...Desert phreatophytes are greatly dependent on groundwater, but how their root systems adapt to different groundwater depths is poorly understood. In the present study, shoot and root growths of Alhagi sparsifolia Shap. seedlings were studied across a gradient of groundwater depths. Leaves, stems and roots of different orders were measured after 120 days of different groundwater treatments. Results indicated that the depth of soil wetting front and the vertical distribution of soil water contents were highly controlled by groundwater depths. The shoot growth and biomass of A. sparsifolia decreased, but the root growth and rooting depth increased under deeper groundwater conditions. The higher ratios of root biomass, root/shoot and root length/leaf area under deeper groundwater conditions implied that seedlings of A. sparsifolia economized carbon cost on their shoot growths. The roots of A. sparsifolia distributed evenly around the soil wetting fronts under deeper groundwater conditions. Root diameters and root lengths of all orders were correlated with soil water availabilities both within and among treatments. Seedlings of A. sparsifolia produced finer first- and second-order roots but larger third- and fourth-order roots in dry soils. The results demonstrated that the root systems of desert phreatophytes can be optimized to acquire groundwater resources and maximize seedling growth by balancing the costs of carbon gain.展开更多
This paper aims at designing a better net-work i,,imozatopm strategy to fight against the Sus- ceptible-Infected-Susceptible （SIS） type epidemic spreading in networks. Previous work used the nurrber of drops in the ...This paper aims at designing a better net-work i,,imozatopm strategy to fight against the Sus- ceptible-Infected-Susceptible （SIS） type epidemic spreading in networks. Previous work used the nurrber of drops in the spectral radius of the net-work for evaluation and guiding the design of im-munization strategies. Instead, we propose using the infected node number in the steady state of SIS spreading as the appropriate metric. We use the metric to point out the limitations of the Equal Graph Partitioning （EGP） strategy and the ＂max-△λ＂ strategy, which are two representative network inmmnization strategies, and then identify the criti-cal role of epidemic spreading parameters in the e-valuation and design of network immuzization strat- egies. Based on all of these, we design a new immuzization strategy. Simulation results show that our strategy performs consistently better than the EGP strategy. In many cases, it uses only 50% less re-sources to achieve the same immuzization effect.展开更多
基金supported by the National Natural Science Foundation of China“Game control-based planning and simulation modelling of coupled optical storage hydrogen production system”(No.52277211).
文摘As renewable energy continues to be integrated into the grid,energy storage has become a vital technique supporting power system development.To effectively promote the efficiency and economics of energy storage,centralized shared energy storage(SES)station with multiple energy storage batteries is developed to enable energy trading among a group of entities.In this paper,we propose the optimal operation with dynamic partitioning strategy for the centralized SES station,considering the day-ahead demands of large-scale renewable energy power plants.We implement a multi-entity cooperative optimization operation model based on Nash bargaining theory.This model is decomposed into two subproblems:the operation profit maximization problem with energy trading and the leasing payment bargaining problem.The distributed alternating direction multiplier method(ADMM)is employed to address the subproblems separately.Simulations reveal that the optimal operation with a dynamic partitioning strategy improves the tracking of planned output of renewable energy entities,enhances the actual utilization rate of energy storage,and increases the profits of each participating entity.The results confirm the practicality and effectiveness of the strategy.
基金supported by open fund of state key laboratory of operation and control of renewable energy&storage systems(China electric power research institute)(No.NYB51202201709).
文摘The time-of-use(TOU)strategy can effectively improve the energy consumption mode of customers,reduce the peak-valley difference of load curve,and optimize the allocation of energy resources.This study presents an Optimal guidance mechanism of the flexible load based on strategies of direct load control and time-of-use.First,this study proposes a period partitioning model,which is based on a moving boundary technique with constraint factors,and the Dunn Validity Index(DVI)is used as the objective to solve the period partitioning.Second,a control strategy for the curtailable flexible load is investigated,and a TOU strategy is utilized for further modifying load curve.Third,a price demand response strategy for adjusting transferable load is proposed in this paper.Finally,through the case study analysis of typical daily flexible load curve,the efficiency and correctness of the proposed method and model are validated and proved.
基金supported by the Joint Funds of National Natural Science Foundation of China (U1203201)the National Natural Science Foundation of China (41371516, 31100144)
文摘Desert phreatophytes are greatly dependent on groundwater, but how their root systems adapt to different groundwater depths is poorly understood. In the present study, shoot and root growths of Alhagi sparsifolia Shap. seedlings were studied across a gradient of groundwater depths. Leaves, stems and roots of different orders were measured after 120 days of different groundwater treatments. Results indicated that the depth of soil wetting front and the vertical distribution of soil water contents were highly controlled by groundwater depths. The shoot growth and biomass of A. sparsifolia decreased, but the root growth and rooting depth increased under deeper groundwater conditions. The higher ratios of root biomass, root/shoot and root length/leaf area under deeper groundwater conditions implied that seedlings of A. sparsifolia economized carbon cost on their shoot growths. The roots of A. sparsifolia distributed evenly around the soil wetting fronts under deeper groundwater conditions. Root diameters and root lengths of all orders were correlated with soil water availabilities both within and among treatments. Seedlings of A. sparsifolia produced finer first- and second-order roots but larger third- and fourth-order roots in dry soils. The results demonstrated that the root systems of desert phreatophytes can be optimized to acquire groundwater resources and maximize seedling growth by balancing the costs of carbon gain.
基金supported by the State Key Development Program of Basic Research of China under Grants No.2007CB307104,No. 2007CB307100
文摘This paper aims at designing a better net-work i,,imozatopm strategy to fight against the Sus- ceptible-Infected-Susceptible （SIS） type epidemic spreading in networks. Previous work used the nurrber of drops in the spectral radius of the net-work for evaluation and guiding the design of im-munization strategies. Instead, we propose using the infected node number in the steady state of SIS spreading as the appropriate metric. We use the metric to point out the limitations of the Equal Graph Partitioning （EGP） strategy and the ＂max-△λ＂ strategy, which are two representative network inmmnization strategies, and then identify the criti-cal role of epidemic spreading parameters in the e-valuation and design of network immuzization strat- egies. Based on all of these, we design a new immuzization strategy. Simulation results show that our strategy performs consistently better than the EGP strategy. In many cases, it uses only 50% less re-sources to achieve the same immuzization effect.
