Title :
Streamer formation and Monte Carlo space-charge field calculation in SF6
Author :
Liu, Jianfen ; Raju, G. R Govinda
Author_Institution :
Dept. of Electr. Eng., Windsor Univ., Ont., Canada
fDate :
4/1/1993 12:00:00 AM
Abstract :
A Monte Carlo simulation is carried out for SF6 in uniform electric fields, with 7% and 14% overvoltages and at two gas densities at each overvoltage. The electron motion and avalanche growth are simulated by tracing individual paths, and the effect of space charge is included by solving the Poisson equation. The streamer propagation, the electron and positive and negative ion distributions and space charge fields are studied in detail as more time has lapsed after voltage application. The simulated streamer shape explains for the first time the dark space in SF6 streamers observed experimentally. It is found that the mechanism of streamer propagation in an attaching gas is different from that in a nonattaching gas. The maximum field enhancement is just behind the streamer or between two successive streamers in SF6. The anode-directed streamer propagates with a velocity of 107 to 108 cm/s, depending on the percentage of overvoltage and the gas number density
Keywords :
Monte Carlo methods; discharges (electric); electric breakdown of gases; electron avalanches; electron density; gaseous insulation; ion density; overvoltage; space charge; sulphur compounds; Monte Carlo simulation; Poisson equation; SF6; anode-directed streamer; attaching gas; dark space; electron avalanche growth; electron distribution; electron motion; gas number density; maximum field enhancement; negative ion distributions; nonattaching gas; overvoltages; path tracing; positive ion distribution; space-charge field calculation; streamer propagation; streamer shape; uniform electric fields; Anodes; Cathodes; Electrons; Helium; Ionization; Monte Carlo methods; Poisson equations; Space charge; Sulfur hexafluoride; Surges;
Journal_Title :
Electrical Insulation, IEEE Transactions on
