One of the main problems in the Ultra High Voltage （UHV） transmission project is to choose the external insulation distance, which requires a deep understanding of the long air gap discharge mechanism. The leader-st...One of the main problems in the Ultra High Voltage （UHV） transmission project is to choose the external insulation distance, which requires a deep understanding of the long air gap discharge mechanism. The leader-streamer propagation is one of most important stages in long air gap discharge. In the conductor-tower lattice configuration, we have measured the voltage, the current on the high voltage side and the electric field in the gap. While the streamer in the leader-streamer system presented a conical or hyperboloid diffuse shape, the clear branch structure streamer in front of the leader was firstly observed by a high speed camera in： the experiment. Besides, it is found that the leader velocity, width and injected charge for the branch type streamer are greater than those of a diffuse type. We propose that the phenomenon results from the high humidity, which was 15.5-16.5 g/m3 in our experiment.展开更多
Establishing a long air gap discharge model considering the streamer-leader transition and randomness of the discharge path is of great signiflcance to improve the accuracy of discharge characteristic prediction and o...Establishing a long air gap discharge model considering the streamer-leader transition and randomness of the discharge path is of great signiflcance to improve the accuracy of discharge characteristic prediction and optimize external insulation design.Based on fractal theory and thermal ionization theory of streamer-leader transition,this work establishes a dynamic development model for the long air gap discharge streamer-leader system,which includes streamer inception,streamer development,leader inception,development of streamer-leader system and flnal jump.The positive discharge process of a 3 m rod plate is simulated to obtain the fractal distribution of the discharge path and the law of leader development for comparison with the discharge test results.The results show that the simulation model is similar to test results in the development characteristics of leader path distribution,each stage time and leader velocity.Finally,a simulation calculation of a 50%breakdown voltage of the rod-plate gap and ball-plate gap is carried out,with results fairly consistent with test data,proving the effectiveness and practicality of the model.展开更多
采用流水线逐级上传的方法解决了电缆外部需要大量缓存的问题,采用基于LVDS(Low Voltage Differential Signaling)和双绞线的传输方式,实现了100m长度下160Mb/s的稳定传输,克服了传统系统中用光纤传输时不易维护的不足。系统在满足高速...采用流水线逐级上传的方法解决了电缆外部需要大量缓存的问题,采用基于LVDS(Low Voltage Differential Signaling)和双绞线的传输方式,实现了100m长度下160Mb/s的稳定传输,克服了传统系统中用光纤传输时不易维护的不足。系统在满足高速率传输的同时,具有成本低、使用方便、安装容易、体积小等优点,使电缆传输成功应用于海上地震数据传输系统。展开更多
基金supported by the Fund of the National Priority Basic Research of China(2011CB209403)National Natural Science Foundation of China(Nos.51325703,51377094,51577098)
文摘One of the main problems in the Ultra High Voltage （UHV） transmission project is to choose the external insulation distance, which requires a deep understanding of the long air gap discharge mechanism. The leader-streamer propagation is one of most important stages in long air gap discharge. In the conductor-tower lattice configuration, we have measured the voltage, the current on the high voltage side and the electric field in the gap. While the streamer in the leader-streamer system presented a conical or hyperboloid diffuse shape, the clear branch structure streamer in front of the leader was firstly observed by a high speed camera in： the experiment. Besides, it is found that the leader velocity, width and injected charge for the branch type streamer are greater than those of a diffuse type. We propose that the phenomenon results from the high humidity, which was 15.5-16.5 g/m3 in our experiment.
基金supported by the Natural Science Foundation of Hebei Province(No.E2021502025)。
文摘Establishing a long air gap discharge model considering the streamer-leader transition and randomness of the discharge path is of great signiflcance to improve the accuracy of discharge characteristic prediction and optimize external insulation design.Based on fractal theory and thermal ionization theory of streamer-leader transition,this work establishes a dynamic development model for the long air gap discharge streamer-leader system,which includes streamer inception,streamer development,leader inception,development of streamer-leader system and flnal jump.The positive discharge process of a 3 m rod plate is simulated to obtain the fractal distribution of the discharge path and the law of leader development for comparison with the discharge test results.The results show that the simulation model is similar to test results in the development characteristics of leader path distribution,each stage time and leader velocity.Finally,a simulation calculation of a 50%breakdown voltage of the rod-plate gap and ball-plate gap is carried out,with results fairly consistent with test data,proving the effectiveness and practicality of the model.
文摘采用流水线逐级上传的方法解决了电缆外部需要大量缓存的问题,采用基于LVDS(Low Voltage Differential Signaling)和双绞线的传输方式,实现了100m长度下160Mb/s的稳定传输,克服了传统系统中用光纤传输时不易维护的不足。系统在满足高速率传输的同时,具有成本低、使用方便、安装容易、体积小等优点,使电缆传输成功应用于海上地震数据传输系统。
