Dark current measurements in humid SF6: influence of electrode roughness, relative humidity and pressure

Laetitia Zavattoni (1) , Rachelle Hanna (1) , Olivier Lesaint (1) , Olivier Gallot-Lavallée (1)

1 G2ELab - Laboratoire de Génie Electrique de Grenoble

The measurement of ‘dark current’ in pressurized SF6 at high electric field is performed using electrodes with a coaxial geometry. To identify the main mechanisms involved in measured currents, the influences of electrode roughness, gas pressure and relative humidity have been investigated. The experimental results reveal that charge injection from the electrode constitute the predominant process responsible for the dark current. The latter is nearly identical in positive and negative polarities, and shows an exponential increase versus the relative humidity and the electric field. The analysis of results shows that under high electric field, the emission of charged water clusters from the water films adsorbed on electrodes probably constitutes the main mechanism of charge emission.

Mots clés: dark currents; SF6; high elecrtic field

Domaines: Energie électrique

Laetitia Zavattoni, Rachelle Hanna, Olivier Lesaint, Olivier Gallot-Lavallée. Dark current measurements in humid SF6: influence of electrode roughness, relative humidity and pressure. Journal of Physics D: Applied Physics, 2015, 48, 375501 (9pp). ⟨hal-01196923⟩