Physico-chemical investigation of the behavior of silicone oils under partial discharge and discharge conditions

Experimental results are reported on the chemical decomposition of Methyl and Phenyl substituted Polysiloxanes under the action of partial discharges and discharges. Gas analysis was carried out and the gas composition was determined as a function of the discharge conditions and of the molecular structure of the oil. Measurements on charge carrier injection and breakdown in inhomogeneous fields were carried out in order to elucidate the mechanisms leading to chemical breakdown. The relevance of these results with respect to ageing is discussed.