Prebreakdown and Breakdown Phenomena in HFO Gas Under Impulse Voltage—Part II: Quasi-Uniform Field

Abstract

Breakdown phenomena in the HFO1234ze(E) gas are studied under impulse voltage in moderately divergent field, with field enhancement factor η < 10. The first breakdown voltage recorded in new HFO with clean electrodes is higher than in SF <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">6</sub> . However, the degradation of HFO by discharges induces the formation of soot deposited on electrodes, which strongly facilitates the inception of subsequent pre-breakdown leaders: both inception field and statistical delay to inception are reduced. As a consequence, the breakdown voltage of HFO with polluted electrodes drops, and becomes lower than in SF <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">6</sub> in identical conditions. This deleterious effect is not recorded in negative polarity.