Power system restoration has attracted more attention and made great progress recently. Research progress of the power system restoration from 2006 to 2016 is reviewed in this paper, including black-start, network rec...Power system restoration has attracted more attention and made great progress recently. Research progress of the power system restoration from 2006 to 2016 is reviewed in this paper, including black-start, network reconfiguration and load restoration. Some emerging methods and key techniques are also discussed in the context of the integration of variable renewable energy and development of the smart grid. There is a long way to go to achieve automatic self-healing in bulk power systems because of its extreme complexity. However, rapidly developing artificial intelligence technology will eventually enable the step-by-step dynamic decision-making based on the situation awareness of supervisory control and data acquisition systems(SCADA) and wide area measurement systems(WAMS) in the near future.展开更多
The conventional structures in the Switched Reluctance machines are introduced, such as three-phase 12/8 structure Switched Reluctance machine, three-phase 6/4 structure Switched Reluctance machine, four-phase 16/12 s...The conventional structures in the Switched Reluctance machines are introduced, such as three-phase 12/8 structure Switched Reluctance machine, three-phase 6/4 structure Switched Reluctance machine, four-phase 16/12 structure Switched Reluctance machine, and four-phase 8/6 structure Switched Reluctance machine. Three-phase 12/8 structure Switched Reluctance machine is the best choice for the large power Switched Reluctance machine system in coal mines. The asymmetric bridge power converter main circuit and the bifilar winding power converter main circuit are also introduced. Three-phase asymmetric bridge power converter main circuit is the best choice for the large power Switched Reluctance machine system in coal mines. The magnetic paths of the designed large power motor are given with one phase excitation and double phases excitation. The phase current waveforms are also given.展开更多
Based on the real-time synchronous measurements of the wind velocity,temperature,the PM10 concentration at 16 m and 47 m during a dust storm event,in which Reynolds number Re exceeds 6×106,this study reveals the ...Based on the real-time synchronous measurements of the wind velocity,temperature,the PM10 concentration at 16 m and 47 m during a dust storm event,in which Reynolds number Re exceeds 6×106,this study reveals the existence of the very large scale motions(VLSMs) during the stable stage both in the stream velocity and the temperature field at the two heights,whose streamwise scales reach up to 10 times the thickness of the boundary layer.The streamwise velocity and the PM10 concentration display a similar frequency corresponding to the peaks of their energy spectra,which implies that the VLSMs of streamwise flow have a significant role in dust transportation.In contrast,the salient deviations of the PM10 concentration at 47 m from the Gaussian distribution are revealed,which means that 47 m is not in the dust transportation layer,but is a region where the dust transportation layer and the outer flow intersect each other.Analysis demonstrates that the energy spectra of the PM10 concentrations at 16 m and 47 m display the "-1" scaling law feature,which has the same frequency range(0.001-0.1 Hz) as that of the wind velocity.This provides a new paradigm for the existence of the self-similarity scaling region in turbulent flow.展开更多
基金supported by National Basic Research Program of China(973 Program)(No.2012CB215101)
文摘Power system restoration has attracted more attention and made great progress recently. Research progress of the power system restoration from 2006 to 2016 is reviewed in this paper, including black-start, network reconfiguration and load restoration. Some emerging methods and key techniques are also discussed in the context of the integration of variable renewable energy and development of the smart grid. There is a long way to go to achieve automatic self-healing in bulk power systems because of its extreme complexity. However, rapidly developing artificial intelligence technology will eventually enable the step-by-step dynamic decision-making based on the situation awareness of supervisory control and data acquisition systems(SCADA) and wide area measurement systems(WAMS) in the near future.
基金Project 2008DFA61870 supported by the International S&T Cooperation Program of Chinathe Project [2008]221-12-1 supported by the Chinese-Bulgarian Scientific and Technological Cooperation Project
文摘The conventional structures in the Switched Reluctance machines are introduced, such as three-phase 12/8 structure Switched Reluctance machine, three-phase 6/4 structure Switched Reluctance machine, four-phase 16/12 structure Switched Reluctance machine, and four-phase 8/6 structure Switched Reluctance machine. Three-phase 12/8 structure Switched Reluctance machine is the best choice for the large power Switched Reluctance machine system in coal mines. The asymmetric bridge power converter main circuit and the bifilar winding power converter main circuit are also introduced. Three-phase asymmetric bridge power converter main circuit is the best choice for the large power Switched Reluctance machine system in coal mines. The magnetic paths of the designed large power motor are given with one phase excitation and double phases excitation. The phase current waveforms are also given.
基金supported by the National Natural Science Foundation of China (Grant Nos. 11232006,11121202,10972164,40830103,and 11072097)the State Key Dvelopment Program for Basic Research of China (Grant No. 2009CB421304)
文摘Based on the real-time synchronous measurements of the wind velocity,temperature,the PM10 concentration at 16 m and 47 m during a dust storm event,in which Reynolds number Re exceeds 6×106,this study reveals the existence of the very large scale motions(VLSMs) during the stable stage both in the stream velocity and the temperature field at the two heights,whose streamwise scales reach up to 10 times the thickness of the boundary layer.The streamwise velocity and the PM10 concentration display a similar frequency corresponding to the peaks of their energy spectra,which implies that the VLSMs of streamwise flow have a significant role in dust transportation.In contrast,the salient deviations of the PM10 concentration at 47 m from the Gaussian distribution are revealed,which means that 47 m is not in the dust transportation layer,but is a region where the dust transportation layer and the outer flow intersect each other.Analysis demonstrates that the energy spectra of the PM10 concentrations at 16 m and 47 m display the "-1" scaling law feature,which has the same frequency range(0.001-0.1 Hz) as that of the wind velocity.This provides a new paradigm for the existence of the self-similarity scaling region in turbulent flow.
