Cable jacket breakdown strength under lightning impulse

Cable failures due to external factors, such as lightning strikes, are frequent in cable systems. The majority of publications focus on the main insulation of cables. Although this is apparently the most critical component in terms of the cable insulating capability, cable jacket is the first protection barrier against external hazards and ensures the integrity of the whole cable. A potential failure in cable jacket may downgrade the cable withstand capability against moisture and, thus, may initiate the breakdown mechanism for its main insulation. Little attention has been paid to the breakdown strength under lightning impulse in the existing literature. The present paper proposes a methodology to conduct impulse tests in cable jackets. Three jacket materials, mostly employed in high voltage and extra high voltage cables, are examined. A full Weibull analysis is performed to evaluate the derived experimental results. Useful findings, allowing for the design optimization of cable jackets, are extracted.