Modern high-voltage electrical equipment operates in complex environments where surface conditions are subjected to multifaceted influences from electric fields,thermal gradients,contaminants,irradiation and other ext...Modern high-voltage electrical equipment operates in complex environments where surface conditions are subjected to multifaceted influences from electric fields,thermal gradients,contaminants,irradiation and other extreme environmental factors.Under high-voltage conditions,surface flashovers frequently initiate at the gas-solid interface of insulators,jeopardising the operational reliability of industrial systems.To address flashover challenges in practical electrical equipment,this review systematically analyses the impact of environmental variables-including gaseous media,voltage waveforms,contaminants and highenergy irradiation-on surface flashover characteristics.Subsequently,we comprehensively synthesise the mechanisms,contributing factors,suppression techniques and enhancement strategies for surface flashover in four critical equipment categories prone to this phenomenon:high pulsed power systems,spacecraft operating in vacuum environments,gas-insulated switchgear/transmission lines(GIS/GIL)and outdoor insulators.The environmental dependencies of flashover behaviour in these systems are rigorously examined.Furthermore,to advance flashover prevention in next-generation industrial applications,this study identifies 25 fundamental scientific questions and 25 technical questions to guide future research directions.By establishing an integrated theoretical framework and methodological foundation for engineering-oriented flashover studies,this work provides actionable insights and mitigation approaches to enhance the surface insulation of modern industrial infrastructure.展开更多
Polarization fluctuation induced noise and backscattering-induced noise are the dominant noises in resonant fiber optic gyroscopes. This Letter proposes a new method to suppress the carrier and backscattering induced ...Polarization fluctuation induced noise and backscattering-induced noise are the dominant noises in resonant fiber optic gyroscopes. This Letter proposes a new method to suppress the carrier and backscattering induced noise by the sideband locking technique. Besides choosing an optimized modulation depth and different clockwise and counterclockwise modulation frequencies, the sideband is locked to the cavity resonance. With the proper modulation frequency, the carrier frequency component locates at a position far away from the resonant frequency, and then it is suppressed by the cavity itself, which can be taken as a bandpass filter. The amplitude of the carrier frequency can be suppressed by 20–25 d B additionally by the cavity and the total intensity suppression ratio can reach 115.74 d B. The backscattering induced noise can be eliminated for the adoption of different frequencies. The method can realize a stable and high suppression ratio without high requirements for parameter accuracy or device performance.展开更多
基金supported by the Natural Science Foundation of China(Grant:52307166)the Natural Science Foundation of Heilongjiang Province(Grant:LH2023E085).
文摘Modern high-voltage electrical equipment operates in complex environments where surface conditions are subjected to multifaceted influences from electric fields,thermal gradients,contaminants,irradiation and other extreme environmental factors.Under high-voltage conditions,surface flashovers frequently initiate at the gas-solid interface of insulators,jeopardising the operational reliability of industrial systems.To address flashover challenges in practical electrical equipment,this review systematically analyses the impact of environmental variables-including gaseous media,voltage waveforms,contaminants and highenergy irradiation-on surface flashover characteristics.Subsequently,we comprehensively synthesise the mechanisms,contributing factors,suppression techniques and enhancement strategies for surface flashover in four critical equipment categories prone to this phenomenon:high pulsed power systems,spacecraft operating in vacuum environments,gas-insulated switchgear/transmission lines(GIS/GIL)and outdoor insulators.The environmental dependencies of flashover behaviour in these systems are rigorously examined.Furthermore,to advance flashover prevention in next-generation industrial applications,this study identifies 25 fundamental scientific questions and 25 technical questions to guide future research directions.By establishing an integrated theoretical framework and methodological foundation for engineering-oriented flashover studies,this work provides actionable insights and mitigation approaches to enhance the surface insulation of modern industrial infrastructure.
文摘Polarization fluctuation induced noise and backscattering-induced noise are the dominant noises in resonant fiber optic gyroscopes. This Letter proposes a new method to suppress the carrier and backscattering induced noise by the sideband locking technique. Besides choosing an optimized modulation depth and different clockwise and counterclockwise modulation frequencies, the sideband is locked to the cavity resonance. With the proper modulation frequency, the carrier frequency component locates at a position far away from the resonant frequency, and then it is suppressed by the cavity itself, which can be taken as a bandpass filter. The amplitude of the carrier frequency can be suppressed by 20–25 d B additionally by the cavity and the total intensity suppression ratio can reach 115.74 d B. The backscattering induced noise can be eliminated for the adoption of different frequencies. The method can realize a stable and high suppression ratio without high requirements for parameter accuracy or device performance.
