Critical switching impulse strength of long air gaps: modelling ofair density effects

摘要

A physical modelling approach is presented to investigate theeffect of reduced air density on leader inception and sparkover of longair gaps under positive switching impulses with critical front time. Themodel accounts for the effect of air density on continuous leaderinception voltage, leader length, and sparkover voltage. The results ofthe model provide critical positive switching impulse air densitycorrection factors for rod-plane, rod-rod, conductor-plane,conductor-rod, and conductor-tower window gaps over a wide range of gapdistances and relative air densities. The model findings wereextensively checked against previous experimental results with quitesatisfactory agreement