${\rm CO}_{2}$ as an Arc Interruption Medium in Gas Circuit Breakers

${\rm CO}_{2}$
is a possible alternative to
${\rm SF}_{6}$
—which has a high global warming potential—as the interruption medium in gas circuit breakers. The performance of
${\rm CO}_{2}$
is investigated in this paper by carrying out experiments in representative test devices and by performing computational fluid dynamic (CFD) simulations; some comparisons with
${\rm SF}_{6}$
and air are given. It is found that the thermal interruption performance of
${\rm CO}_{2}$
is lower than that of
${\rm SF}_{6}$
, but higher than that of air. The measured dielectric recovery after arcing is compared for
${\rm CO}_{2}$
and
${\rm SF}_{6}$
; a streamer model is used to calculate the breakdown voltage in
${\rm CO}_{2}$
; good agreement with measurement is found. The speed of sound and the adiabatic coefficient, important parameters that influence pressure buildup and gas flow, are compared for
${\rm SF}_{6}$
,
${\rm CO}_{2}$
, and air. CFD simulations of the pressure buildup in
${\rm CO}_{2}$
and
${\rm SF}_{6}$
both illustrate the qualitative differences between the two and show good agreement with measurements.