Title :
TSDC investigations of thermally and electro-thermally aged cable models
Author :
Gubanski, S.M. ; Montanari, G.C. ; Motori, A.
Author_Institution :
Dept. of Electr. Plant Eng., R. Inst. of Technol., Stockholm, Sweden
Abstract :
Classical TSD and fractional polarisation analyses were carried out on unaged and aged XLPE cable models from -120°C to 120°C and three relaxation processes were found. A low temperature process, identified as β relaxation and ascribed to the polar groups attached to the polymer chains in the amorphous region, gets stronger with duration of the aging and can be mainly ascribed to an increase in carbonyl group concentration. The second polarisation process, that exhibits itself by a strong TSD peak at a temperature range 50-80°C and is only present in the spectra of aged samples, is believed to be caused by a charge relaxation. The high temperature peak, present above 100°C, can be related to melting of crystalline phase in the polymer. This peak should also be related to charge polarisation process. Fractional depolarisation measurements allowed for a precise description of elementary processes (activation energies and preexponential factors)
Keywords :
XLPE insulation; ageing; dielectric depolarisation; dielectric polarisation; dielectric relaxation; power cable insulation; thermally stimulated currents; -120 to 120 degC; TSDC investigations; XLPE cable models; activation energies; carbonyl group concentration; charge relaxation; crystalline phase melting; electro-thermally aged cable models; elementary processes; fractional polarisation analyses; polar groups; preexponential factors; relaxation processes; Aging; Atmospheric measurements; Cable insulation; Conductors; Current measurement; Performance evaluation; Polarization; Polymers; Temperature; Wire;
Conference_Titel :
Electrical Insulation, 1994., Conference Record of the 1994 IEEE International Symposium on
Conference_Location :
Pittsburgh, PA
Print_ISBN :
0-7803-1942-7
DOI :
10.1109/ELINSL.1994.401469
