Open-circuit Thermally Stimulated Currents in LDPE/Al2O3 Nanocomposite

Paper in proceeding, 2016

Polyethylene doped with nanoparticles of inorganic oxides has been studied extensively during the last decade, aiming at its possible use as suitable material in insulation of high voltage direct current cables. To elucidate electrical properties of such material, thermally stimulated discharge (TSD) currents are analyzed in samples of low-density polyethylene (LDPE) filled with Al2O3 nanoparticles and compared with the response of pure LDPE. The latter exhibits a presence of two peaks in the TSD spectrum, which yield levels of activation energies close to earlier published data. For LDPE nanocomposite, a single broad peak is found instead, which when decomposed into a number of single peaks yields higher and broadly spreading activation energies. This indicates a presence of deep traps in the nanocomposite and explains significant reduction of its DC conductivity and strong suppression of space charge accumulation, as compared with unfilled LDPE.