The air gap at the interface inside the cable terminations for high-speed trains and the partial discharge caused by it are two important factors affecting the insulating performance.The development of air gap and par...The air gap at the interface inside the cable terminations for high-speed trains and the partial discharge caused by it are two important factors affecting the insulating performance.The development of air gap and partial discharge will eventually lead to breakdown faults.To investigate the evolutionary characteristics of the air gap and partial discharge,the simulation models and samples of cable terminations containing defects are constructed in this paper.By analysing the variation law of the electric field and the multidimensional information of partial discharge,the evolution process of the air gap is divided into four wellcharacterised stages.Especially in the third stage,the partial discharge extinction voltage is 51.41%lower than that of the defect-free samples and even lower than the working voltage.The asymmetry of discharge is the most significant factor.The volume of discharge in the third quadrant is significantly higher than that in the first quadrant.This important feature can be applied to the inspection and evaluation of the insulating state of the cable terminations.The partial discharge characteristics of the air gap revealed in this paper are proposed to provide an important theoretical supplement to the study of interface discharges between heterogeneous dielectrics.展开更多
To accurately diagnose the aging condition of the vehicle-mounted high-voltage cable terminals under the combined electro-thermal stress,this paper proposes a terahertz frequency spectrum technology-based method.First...To accurately diagnose the aging condition of the vehicle-mounted high-voltage cable terminals under the combined electro-thermal stress,this paper proposes a terahertz frequency spectrum technology-based method.First,an electro-thermal aging platform is established in the laboratory to obtain the test samples of ethylene-propylene rubber(EPR)cable terminals with different aging gradients.Then,the degree of electro-thermal aging is characterized by frequency spectrum,absorption coefficient spectrum,absorption spectrum,refractive index and dielectric constant in the terahertz domain.Moreover,the micro-morphology and micro-area structure of the test samples under different aging gradients are also observed by scanning electron microscopy,and both the material and chemical properties are analyzed.The findings demonstrate that terahertz frequency spectra offer significant benefits in non-destructively detecting and identifying the insulation condition of vehicle cable terminals during electro-thermal aging.Laboratory tests confirm the feasibility of utilizing the terahertz frequency spectrum to assess the insulation aging state of EPR cable terminals,making it potentially applicable for on-site purposes.展开更多
基金supported by National Natural Science Foundation of China,Grant/Award Number:52377161.
文摘The air gap at the interface inside the cable terminations for high-speed trains and the partial discharge caused by it are two important factors affecting the insulating performance.The development of air gap and partial discharge will eventually lead to breakdown faults.To investigate the evolutionary characteristics of the air gap and partial discharge,the simulation models and samples of cable terminations containing defects are constructed in this paper.By analysing the variation law of the electric field and the multidimensional information of partial discharge,the evolution process of the air gap is divided into four wellcharacterised stages.Especially in the third stage,the partial discharge extinction voltage is 51.41%lower than that of the defect-free samples and even lower than the working voltage.The asymmetry of discharge is the most significant factor.The volume of discharge in the third quadrant is significantly higher than that in the first quadrant.This important feature can be applied to the inspection and evaluation of the insulating state of the cable terminations.The partial discharge characteristics of the air gap revealed in this paper are proposed to provide an important theoretical supplement to the study of interface discharges between heterogeneous dielectrics.
基金supported in part by the National Natural Science Foundation of China(52167018)Opening Foundation of the National Rail Transportation Electrification and Automation Engineering Technology ResearchCenter(NEEC-2022-B19).
文摘To accurately diagnose the aging condition of the vehicle-mounted high-voltage cable terminals under the combined electro-thermal stress,this paper proposes a terahertz frequency spectrum technology-based method.First,an electro-thermal aging platform is established in the laboratory to obtain the test samples of ethylene-propylene rubber(EPR)cable terminals with different aging gradients.Then,the degree of electro-thermal aging is characterized by frequency spectrum,absorption coefficient spectrum,absorption spectrum,refractive index and dielectric constant in the terahertz domain.Moreover,the micro-morphology and micro-area structure of the test samples under different aging gradients are also observed by scanning electron microscopy,and both the material and chemical properties are analyzed.The findings demonstrate that terahertz frequency spectra offer significant benefits in non-destructively detecting and identifying the insulation condition of vehicle cable terminals during electro-thermal aging.Laboratory tests confirm the feasibility of utilizing the terahertz frequency spectrum to assess the insulation aging state of EPR cable terminals,making it potentially applicable for on-site purposes.
