With the rapid development of large-scale regional interconnected power grids,the risk of cascading failures under extreme condi-tions,such as natural disasters and military strikes,has increased significantly.To enha...With the rapid development of large-scale regional interconnected power grids,the risk of cascading failures under extreme condi-tions,such as natural disasters and military strikes,has increased significantly.To enhance the response capability of power systems to extreme events,this study focuses on a method for generator coherency detection.To overcome the shortcomings of the traditional slow coherency method,this paper introduces a novel coherent group identification algorithm based on the theory of nonlinear dynam-ical systems.By analyzing the changing trend of the Euclidean norm of the state variable derivatives in the reduced system,the algorithm can accurately identify the magnitude of the disturbances.Based on the slow coherency methods,the algorithm can correctly recognize coherent generator groups by analyzing system characteristics under varying disturbance magnitudes.This improvement enhances the applicability and accuracy of the coherency detection algorithm under extreme conditions,providing support for emergency control and protection in the power system.Simulations and comparison analyses on IEEE 39-bus system are conducted to validate the accuracy and superiority of the proposed coherent generator group identification method under extreme conditions.展开更多
With the shadowgraph method, three ultrasonic pulses in Water, which correspond to the conversion modes of the fast compressional wave, the transverse wave and the slow compressional wave in the sample of Fluid-Satura...With the shadowgraph method, three ultrasonic pulses in Water, which correspond to the conversion modes of the fast compressional wave, the transverse wave and the slow compressional wave in the sample of Fluid-Saturated Porous Medium (FSPM) respectively,were observed and recorded by CCD camera. The positions of these pulses are cousistent with the computed positions and the time interval between these pulses measured by a transmitterreceiver method.展开更多
We report the growth of high quality Fe excess and Co doped,FeTxSe single crystals in nominal ratio via slow cooling method of high temperature solution growth technique and,their structural and physical properties th...We report the growth of high quality Fe excess and Co doped,FeTxSe single crystals in nominal ratio via slow cooling method of high temperature solution growth technique and,their structural and physical properties through the X‐ray diffraction,Raman spectroscopy,magnetic and transports measurements.Selective area electron diffraction(SAED)patterns and X‐ray diffraction of cleavage piece confirm the growth of single crystals in(h0l)orientations.Observations of phonon vibration modes(A_(1g) and B_(1g))in Raman spectroscopy measurements mark the qualitative analysis of these single crystals.Low temperature magnetic and electrical transport studies manifest the superconducting nature of both single crystals.展开更多
基金supported by National Natural Science Foundation of China(Grant No:52477133)Science and Technology Project of China Southern Power Grid(Grant No.GDKJXM20231178(036100KC23110012)+1 种基金GDKJXM20240389(030000KC24040053))Sanya Yazhou Bay Science and Technology City(Grant No:SKJC-JYRC-2024-66).
文摘With the rapid development of large-scale regional interconnected power grids,the risk of cascading failures under extreme condi-tions,such as natural disasters and military strikes,has increased significantly.To enhance the response capability of power systems to extreme events,this study focuses on a method for generator coherency detection.To overcome the shortcomings of the traditional slow coherency method,this paper introduces a novel coherent group identification algorithm based on the theory of nonlinear dynam-ical systems.By analyzing the changing trend of the Euclidean norm of the state variable derivatives in the reduced system,the algorithm can accurately identify the magnitude of the disturbances.Based on the slow coherency methods,the algorithm can correctly recognize coherent generator groups by analyzing system characteristics under varying disturbance magnitudes.This improvement enhances the applicability and accuracy of the coherency detection algorithm under extreme conditions,providing support for emergency control and protection in the power system.Simulations and comparison analyses on IEEE 39-bus system are conducted to validate the accuracy and superiority of the proposed coherent generator group identification method under extreme conditions.
文摘With the shadowgraph method, three ultrasonic pulses in Water, which correspond to the conversion modes of the fast compressional wave, the transverse wave and the slow compressional wave in the sample of Fluid-Saturated Porous Medium (FSPM) respectively,were observed and recorded by CCD camera. The positions of these pulses are cousistent with the computed positions and the time interval between these pulses measured by a transmitterreceiver method.
基金support through the project No.F.30‐303/2016(BSR).
文摘We report the growth of high quality Fe excess and Co doped,FeTxSe single crystals in nominal ratio via slow cooling method of high temperature solution growth technique and,their structural and physical properties through the X‐ray diffraction,Raman spectroscopy,magnetic and transports measurements.Selective area electron diffraction(SAED)patterns and X‐ray diffraction of cleavage piece confirm the growth of single crystals in(h0l)orientations.Observations of phonon vibration modes(A_(1g) and B_(1g))in Raman spectroscopy measurements mark the qualitative analysis of these single crystals.Low temperature magnetic and electrical transport studies manifest the superconducting nature of both single crystals.
