Analysis of Mineral Oil Cracking Mechanisms in Discharge Faults

Mineral oil has been extensively and widely used as an insulating medium for a long time. However, the mechanisms underlying discharges in oil are not yet fully understood, and a comprehensive discharge theory comparable to that for gaseous discharges remains elusive. This paper, based on the theory of electrical discharges in liquid dielectrics, investigates the primary causes and dominant mechanisms responsible for variations in mineral oil cracking and gas production under different severities of discharge-related faults. The impact of high-energy electron collisions, discharge channel temperature rise, and optical radiation on mineral oil cracking during discharge are analyzed. The results indicate that the discharge ionization intensity and the discharge channel temperature are the key factors contributing to differences in insulating oil cracking and gas generation. Furthermore, variations in discharge development speed, discharge channel length, and temperature during discharge evolution lead to differences in ionization modes and intensities. This manifests as the combined effects of high-energy electron collisions, discharge channel temperature rise, and optical radiation on insulating oil cracking, ultimately resulting in variations in the content and ratios of characteristic gases generated.