As global energy systems transition toward high shares of renewable energy,maintaining frequency stability becomes increasingly challenging in the case of the reduced inertia and dispatchability of inverter-based reso...As global energy systems transition toward high shares of renewable energy,maintaining frequency stability becomes increasingly challenging in the case of the reduced inertia and dispatchability of inverter-based resources.Power generation,including renewable energy technologies as well as thermal power generation,continues to serve a vital role in frequency regulation of power grids but confronts accelerating operational issues,especially when tackling frequent,rapid cycling.Flywheels with their fast response,high power density,long cycle life,and minimal environmental drawbacks,have emerged as promising auxiliary resources for enhancing flexibility in frequency regulation challenges.This paper presents a comprehensive review of flywheel technology development and its limitations,followed by an introduction to the diverse types of grid-scale high-power flywheel energy storage systems.Overviews of the flywheel-assisted power grid paradigm,focusing on advanced flywheel technologies,coordinated control strategies,and economic optimizations in electrical trading markets,are also summarized.The electricity trading market mechanisms,including ancillary service reforms and capacity payments,which reshape power grid balancing by leveraging the role of fastresponse storage,are further investigated and discussed.Finally,practical pilot implementations are examined in regions such as Shanxi and Ningxia,China,and Bacon,the United States,demonstrating the efficacy of the independent Flywheel Energy Storage System(FESS)and assisted power generation.This insight expands the research landscape and provides new directions including the interoperability of FESS with low-inertia grids,comprehensive lifecycle assessment,integration within hybrid storage topologies,and the design of investment incentives to promote large-scale adoption.展开更多
Considering the characteristics of the UHVAC Pilot Project in China,the importance of study on electromagnetic transient overvoltage in UHVAC projects is demonstrated in this paper.Through analysis and comparison on t...Considering the characteristics of the UHVAC Pilot Project in China,the importance of study on electromagnetic transient overvoltage in UHVAC projects is demonstrated in this paper.Through analysis and comparison on the simulation programs for electromagnetic transient overvoltages,EMTP is then recommended for the UHVAC Pilot Project in China.The element models in EMTP used in simulating power frequency overvoltage and power resonance of non-entire phase operation,etc.,are introduced.The paper also points out that extra attention will be needed when simulating power frequency sequence parameters and line corona.The research outcome provides valuable references for both oversea and domestic UHVAC projects.展开更多
On June 21, the presentation ceremony for China Home textile Color Application Pilot Base took place in Rui’an Municipal Conference Center of Zhejiang province. Distinguish vips, like Mr. Yang Donghui, Vice Preside...On June 21, the presentation ceremony for China Home textile Color Application Pilot Base took place in Rui’an Municipal Conference Center of Zhejiang province. Distinguish vips, like Mr. Yang Donghui, Vice President of China National Textile and展开更多
Agricultural product price index insurance is a kind of index insurance. It avoids defects of traditional agricultural insurance,such as moral hazards,adverse selection,and high management cost. On the basis of studyi...Agricultural product price index insurance is a kind of index insurance. It avoids defects of traditional agricultural insurance,such as moral hazards,adverse selection,and high management cost. On the basis of studying agricultural product price index insurance of all areas of China,this paper analyzed characteristics of agricultural product price index insurance from object selection,product object,premium design,and policy support,and discussed feasibility of extending agricultural product price index insurance in an all-round way.展开更多
基金supported in part by the National Natural Science Foundation of China(No.52376007).
文摘As global energy systems transition toward high shares of renewable energy,maintaining frequency stability becomes increasingly challenging in the case of the reduced inertia and dispatchability of inverter-based resources.Power generation,including renewable energy technologies as well as thermal power generation,continues to serve a vital role in frequency regulation of power grids but confronts accelerating operational issues,especially when tackling frequent,rapid cycling.Flywheels with their fast response,high power density,long cycle life,and minimal environmental drawbacks,have emerged as promising auxiliary resources for enhancing flexibility in frequency regulation challenges.This paper presents a comprehensive review of flywheel technology development and its limitations,followed by an introduction to the diverse types of grid-scale high-power flywheel energy storage systems.Overviews of the flywheel-assisted power grid paradigm,focusing on advanced flywheel technologies,coordinated control strategies,and economic optimizations in electrical trading markets,are also summarized.The electricity trading market mechanisms,including ancillary service reforms and capacity payments,which reshape power grid balancing by leveraging the role of fastresponse storage,are further investigated and discussed.Finally,practical pilot implementations are examined in regions such as Shanxi and Ningxia,China,and Bacon,the United States,demonstrating the efficacy of the independent Flywheel Energy Storage System(FESS)and assisted power generation.This insight expands the research landscape and provides new directions including the interoperability of FESS with low-inertia grids,comprehensive lifecycle assessment,integration within hybrid storage topologies,and the design of investment incentives to promote large-scale adoption.
文摘Considering the characteristics of the UHVAC Pilot Project in China,the importance of study on electromagnetic transient overvoltage in UHVAC projects is demonstrated in this paper.Through analysis and comparison on the simulation programs for electromagnetic transient overvoltages,EMTP is then recommended for the UHVAC Pilot Project in China.The element models in EMTP used in simulating power frequency overvoltage and power resonance of non-entire phase operation,etc.,are introduced.The paper also points out that extra attention will be needed when simulating power frequency sequence parameters and line corona.The research outcome provides valuable references for both oversea and domestic UHVAC projects.
文摘On June 21, the presentation ceremony for China Home textile Color Application Pilot Base took place in Rui’an Municipal Conference Center of Zhejiang province. Distinguish vips, like Mr. Yang Donghui, Vice President of China National Textile and
基金Supported by the National Social Science Foundation of China(16BJY136) in 2016the Consultant Project of Chinese Academy of Engineering(07-XY-003) in 2015
文摘Agricultural product price index insurance is a kind of index insurance. It avoids defects of traditional agricultural insurance,such as moral hazards,adverse selection,and high management cost. On the basis of studying agricultural product price index insurance of all areas of China,this paper analyzed characteristics of agricultural product price index insurance from object selection,product object,premium design,and policy support,and discussed feasibility of extending agricultural product price index insurance in an all-round way.
