Title :
Thermal ageing of oil-paper insulation
Author :
Morais, R.M. ; Engelstein, E.
Author_Institution :
CEPEL, Centro de Pesquisas de Energie Eletrica, Rio de Janeiro, Brazil
Abstract :
Detailed knowledge of the behavior of oil-paper insulating systems under accelerated thermal load is of interest in the operation of power transformers under increased electrical demands. The authors report on experiments on neutral kraft paper and naphthenic mineral insulating oil. These materials were aged in specially designed glass cells at 125, 140, and 155°C for periods varying from 100 to 4000 h in a nitrogen atmosphere. Degradation was evaluated by mechanical tests (paper) and physical-chemical electrical tests (paper and oil). Results are presented and discussed. Of the physical-chemical and electrical tests carried out on insulating oil, only those on furfuraldehyde, water, and dissolved CO content gave good correlation with the DP (degree of polymerization) values of degraded paper
Keywords :
ageing; composite insulating materials; environmental degradation; environmental testing; insulating oils; insulation testing; paper; power transformers; thermal stresses; transformer insulation; 100 to 4000 hr; 125 to 115 degC; N2 atmosphere; accelerated thermal load; degraded paper; dissolved CO content; electrical tests; furfuraldehyde; glass cells; mechanical tests; naphthenic mineral insulating oil; neutral kraft paper; oil-paper insulation; physical-chemical tests; power transformers; thermal ageing; water; Acceleration; Aging; Dielectrics and electrical insulation; Minerals; Oil insulation; Petroleum; Power transformer insulation; Power transformers; Testing; Thermal loading;
Conference_Titel :
Conduction and Breakdown in Dielectric Liquids, 1990. ICDL 1990. Conference Record., 10th International Conference on
Conference_Location :
Grenoble
DOI :
10.1109/ICDL.1990.202952
