摘要
The leader propagation is one of the most important stages in long air gap discharge.The mechanism behind leader re-illumination remains unclear.In high humidity conditions(20.0–30.1 g/m^(3)),we have conducted experiments of long sparks in a 10 m ultra-high voltage(UHV)transmission line gap under switching impulse voltages.The positive leaders predominantly propagate discontinuously,with almost no significantly continuous propagation occurring.The leader channels are intensely luminous and each elongation segment is straight,with streamers resembling the“branch type”which differs from the“diffuse type”streamers at the front of continuous propagation leaders.The distribution of the propagation velocities is highly random(3.7–18.4 cm/μs),and the average velocity(9.2 cm/μs)significantly exceeds that of continuous propagation(1.5–2.0 cm/μs).Analysis suggests that the current-velocity models suitable for continuous leader propagation do not align well with the experimental data in re-illumination mode.Based on the discharge current waveforms and optical images,it is speculated that the newly elongated leader in re-illumination mode does not evolve gradually from the stem(about 1 cm)but rather evolves overall from a thermal channel much longer than stem.
作者
Biao HUANG
Xuan ZHOU
She WANG
Chijie ZHUANG
Rong ZENG
Le DENG
黄标;周旋;王涉;庄池杰;曾嵘;邓乐(Eliet Engineering School,Changsha University of Science&Technology,Changsha 410114,People’s Republic of China;State Key Laboratory of Disaster Prevention&Reduction for Power Grid,Changsha University of Science&Technology,Changsha 410114,People’s Republic of China;China International Engineering Consulting Co.,Ltd.,Beijing 100048,People’s Republic of China;Department of Electrical Engineering,Tsinghua University,Beijing 100084,People’s Republic of China)
基金
supported by National Key R&D Program of China(No.2022YFB3206800)
Scientific Research Fund of Hunan Provincial Education Department(No.23A0240)
Scientific Research Fund of Hunan Provincial Education Department(No.23C0128)
CSUST Training Program of Innovation and Entrepreneurship for Undergraduates(No.202410536044)。
