The fault branching phenomenon,which may heavily influence the patterns of rupture propagation in fault systems,is one of the geometric complexities of fault systems that is widely observed in nature.In this study,we ...The fault branching phenomenon,which may heavily influence the patterns of rupture propagation in fault systems,is one of the geometric complexities of fault systems that is widely observed in nature.In this study,we investigate the effect of the branching angle on the rupture inclination and the interaction between branch planes in two-fork branching fault systems by numerical simulation and theoretical analysis based on Mohr’s circle.A friction law dependent on normal stress is used,and special attention is paid to studying how ruptures on the upper and lower branch planes affect the stress and rupture on each other separately.The results show that the two branch planes affect each other in different patterns and that the intensity of the effect changes with the branching angle.The rupture of the lower branch plane has a negative effect on the rupture of the upper branch plane in the case of a small branching angle but has almost no negative effect in the case of a large branching angle.The rupture of the upper branch plane,however,suppresses the rupture of the lower branch plane regardless of whether the branching angle is large or small.展开更多
Rotor vibration characteristics are first analyzed, which are that the rotor vibration of fundamental frequency will increase due to rotor winding inter-turn short circuit fault, air-gap dynamic eccentricity fault, or...Rotor vibration characteristics are first analyzed, which are that the rotor vibration of fundamental frequency will increase due to rotor winding inter-turn short circuit fault, air-gap dynamic eccentricity fault, or imbalance fault, and the vibration of the second frequency will increase when the air-gap static eccentricity fault occurs. Next, the characteristics of the stator winding parallel branches circulating current are analyzed, which are that the second harmonics circulating current will increase when the rotor winding inter-turn short circuit fault occurs, and the fundamental circulating current will increase when the air-gap eccentricity fault occurs, neither being strongly affected by the imbalance fault. Considering the differences of the rotor vibration and circulating current characteristics caused by different rotor faults, a method of generator vibration fault diagnosis, based on rotor vibration and circulating current characteristics, is developed. Finally, the rotor vibration and circulating current of a type SDF-9 generator is measured in the laboratory to verify the theoretical analysis presented above.展开更多
基金This study is supported in part by the National Natural Science Foundation of China(grant no.41674050)and by the High-Performance Computing Platform of Peking University.
文摘The fault branching phenomenon,which may heavily influence the patterns of rupture propagation in fault systems,is one of the geometric complexities of fault systems that is widely observed in nature.In this study,we investigate the effect of the branching angle on the rupture inclination and the interaction between branch planes in two-fork branching fault systems by numerical simulation and theoretical analysis based on Mohr’s circle.A friction law dependent on normal stress is used,and special attention is paid to studying how ruptures on the upper and lower branch planes affect the stress and rupture on each other separately.The results show that the two branch planes affect each other in different patterns and that the intensity of the effect changes with the branching angle.The rupture of the lower branch plane has a negative effect on the rupture of the upper branch plane in the case of a small branching angle but has almost no negative effect in the case of a large branching angle.The rupture of the upper branch plane,however,suppresses the rupture of the lower branch plane regardless of whether the branching angle is large or small.
基金This project is supported by Provincial Science Foundation of Education Office of Hebei(No.Z2004455)Youth Research Fundation of State Power of China(No.SPQKJ02-10).
文摘Rotor vibration characteristics are first analyzed, which are that the rotor vibration of fundamental frequency will increase due to rotor winding inter-turn short circuit fault, air-gap dynamic eccentricity fault, or imbalance fault, and the vibration of the second frequency will increase when the air-gap static eccentricity fault occurs. Next, the characteristics of the stator winding parallel branches circulating current are analyzed, which are that the second harmonics circulating current will increase when the rotor winding inter-turn short circuit fault occurs, and the fundamental circulating current will increase when the air-gap eccentricity fault occurs, neither being strongly affected by the imbalance fault. Considering the differences of the rotor vibration and circulating current characteristics caused by different rotor faults, a method of generator vibration fault diagnosis, based on rotor vibration and circulating current characteristics, is developed. Finally, the rotor vibration and circulating current of a type SDF-9 generator is measured in the laboratory to verify the theoretical analysis presented above.
