The effect of steep-front short-duration pulses on polyethylene cable insulation

The authors study the effect of steep-front short-duration (SFSD) impulses on 15-kV cross-linked polyethylene (XLPE) cable insulation. They use a laboratory simulation of fast rise-time pulses that are being, and/or have the potential of being, observed on power systems. A special steep-front pulser was constructed which is capable of producing risetimes below 60 ns. The cables were subjected to these pulses to determine the degradation of the insulation as a function of applied voltage and the number of impulses. The voltage breakdown level as a function of the number of applied shots was determined for cable supplied from two different manufacturers. It is concluded that the voltage breakdown strength appears to be the most repeatable and accurate indicator of the degradation of the XLPE cable insulation as a function of repeated SFSD impulse applications and voltage levels