STUDY ON THE MORPHOLOGY OF XLPE POWER CABLE BY MEANS OF ATOMIC-FORCE MICROSCOPY

The long-term dielectric performance of underground power cable XLPE ( crosslinked polyethylene) insulation suffers from poorly understood ag ing phenomena. A study of the morphological modifications of XLPE due to electrical aging may provide insight for a better understanding of aging mechanisms. The AFM (atomic force microscopy) technique has been used to study XLPE morphology of unaged, laboratory-aged and field-ag ed samples, whereby the soft XLPE surfaces were scanned with an oscill ating AFM probe, to decrease the probability of surface modification. Images recorded on plasma-etched surfaces show many more structural de tails than on unetched surfaces. A XLPE cryo-microtomed surface from a n unaged cable has been exposed to a low-energy electron beam, followi ng which the exposed surface showed striking similarities with that of a field-aged cable.