With the specific characteristics of low-carbon intensity and economy,wind power has been widely promoted around the world.Due to the variable and intermittent nature of wind power production,the system has to frequen...With the specific characteristics of low-carbon intensity and economy,wind power has been widely promoted around the world.Due to the variable and intermittent nature of wind power production,the system has to frequently redispatch generators in order to ensure the effective use of wind power whilst maintaining system security.In this way,traditional generation costs are increased and the social benefit of wind power decreases indirectly.In this paper,a new regulation strategy based on power flow tracing was proposed,taking advantage of a comfort-constrained demand response strategy to follow the fluctuations of wind farm output,with the remaining imbalance of active power compensated by traditional generators.Examples showed that compared with conventional regulation,demand response could reduce the gross operating costs of the system,and the rapid response could help maintaining system stability in case of contingency.The strategy in this paper also applies to other large-scale integration problems associated with renewable energy resources which display short-term production variability.展开更多
Hypersonic and high-enthalpy wind tunnels and their measurement techniques are the cornerstone of the hypersonic flight era that is a dream for human beings to fly faster,higher and further.The great progress has been...Hypersonic and high-enthalpy wind tunnels and their measurement techniques are the cornerstone of the hypersonic flight era that is a dream for human beings to fly faster,higher and further.The great progress has been achieved during the recent years and their critical technologies are still in an urgent need for further development.There are at least four kinds of hypersonic and high-enthalpy wind tunnels that are widely applied over the world and can be classified according to their operation modes.These wind tunnels are named as air-directly-heated hypersonic wind tunnel,light-gas-heated shock tunnel,free-piston-driven shock tunnel and detonation-driven shock tunnel,respectively.The critical technologies for developing the wind tunnels are introduced in this paper,and their merits and weakness are discussed based on wind tunnel performance evaluation.Measurement techniques especially developed for high-enthalpy flows are a part of the hypersonic wind tunnel technology because the flow is a chemically reacting gas motion and its diagnosis needs specially designed instruments.Three kinds of the measurement techniques considered to be of primary importance are introduced here,including the heat flux sensor,the aerodynamic balance,and optical diagnosis techniques.The techniques are developed usually for conventional wind tunnels,but further improved for hypersonic and high-enthalpy tunnels.The hypersonic ground test facilities have provided us with most of valuable experimental data on high-enthalpy flows and will play a more important role in hypersonic research area in the future.Therefore,several prospects for developing hypersonic and high-enthalpy wind tunnels are presented from our point of view.展开更多
Large-scale wind power penetration can affect the supply continuity in the power system.This is a matter of high priority to investigate,as more regulating reserves and specified control strategies for generation cont...Large-scale wind power penetration can affect the supply continuity in the power system.This is a matter of high priority to investigate,as more regulating reserves and specified control strategies for generation control are required in the future power system with even more high wind power penetration.This paper evaluates the impact of large-scale wind power integration on future power systems.An active power balance control methodology is used for compensating the power imbalances between the demand and the generation in real time,caused by wind power forecast errors.The methodology for the balance power control of future power systems with large-scale wind power integration is described and exemplified considering the generation and power exchange capacities in2020 for Danish power system.展开更多
基金supported by Special Fund of the National Basic Research Program of China ("973" Program),Grant Nos. 2009CB219701,2010CB234608)Tianjin Municipal Science and Technology Development Program of China (Grant No. 09JCZDJC25000)+1 种基金Research Fund for the Doctoral Program of Higher Education of China (Grant No.20090032110064)Pacific Institute for Climate Solutions (PICS)
文摘With the specific characteristics of low-carbon intensity and economy,wind power has been widely promoted around the world.Due to the variable and intermittent nature of wind power production,the system has to frequently redispatch generators in order to ensure the effective use of wind power whilst maintaining system security.In this way,traditional generation costs are increased and the social benefit of wind power decreases indirectly.In this paper,a new regulation strategy based on power flow tracing was proposed,taking advantage of a comfort-constrained demand response strategy to follow the fluctuations of wind farm output,with the remaining imbalance of active power compensated by traditional generators.Examples showed that compared with conventional regulation,demand response could reduce the gross operating costs of the system,and the rapid response could help maintaining system stability in case of contingency.The strategy in this paper also applies to other large-scale integration problems associated with renewable energy resources which display short-term production variability.
基金the support of the National Natural Science Foundation of China(Nos.11532014,11727901,11672308 and 11672357)the National Key Research and Development Program of China(No.2019YFA0405204)。
文摘Hypersonic and high-enthalpy wind tunnels and their measurement techniques are the cornerstone of the hypersonic flight era that is a dream for human beings to fly faster,higher and further.The great progress has been achieved during the recent years and their critical technologies are still in an urgent need for further development.There are at least four kinds of hypersonic and high-enthalpy wind tunnels that are widely applied over the world and can be classified according to their operation modes.These wind tunnels are named as air-directly-heated hypersonic wind tunnel,light-gas-heated shock tunnel,free-piston-driven shock tunnel and detonation-driven shock tunnel,respectively.The critical technologies for developing the wind tunnels are introduced in this paper,and their merits and weakness are discussed based on wind tunnel performance evaluation.Measurement techniques especially developed for high-enthalpy flows are a part of the hypersonic wind tunnel technology because the flow is a chemically reacting gas motion and its diagnosis needs specially designed instruments.Three kinds of the measurement techniques considered to be of primary importance are introduced here,including the heat flux sensor,the aerodynamic balance,and optical diagnosis techniques.The techniques are developed usually for conventional wind tunnels,but further improved for hypersonic and high-enthalpy tunnels.The hypersonic ground test facilities have provided us with most of valuable experimental data on high-enthalpy flows and will play a more important role in hypersonic research area in the future.Therefore,several prospects for developing hypersonic and high-enthalpy wind tunnels are presented from our point of view.
基金funded by Sino-Danish Centre for Education and Research (SDC)
文摘Large-scale wind power penetration can affect the supply continuity in the power system.This is a matter of high priority to investigate,as more regulating reserves and specified control strategies for generation control are required in the future power system with even more high wind power penetration.This paper evaluates the impact of large-scale wind power integration on future power systems.An active power balance control methodology is used for compensating the power imbalances between the demand and the generation in real time,caused by wind power forecast errors.The methodology for the balance power control of future power systems with large-scale wind power integration is described and exemplified considering the generation and power exchange capacities in2020 for Danish power system.
