Open AccessAging assessment of kraft paper insulation through methanol in oil measurement
Author(s) -
S. Y. Matharage,
Q. Liu,
Z. D. Wang
Publication year - 2016
Publication title -
ieee transactions on dielectrics and electrical insulation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 119
eISSN - 1558-4135
pISSN - 1070-9878
DOI - 10.1109/tdei.2016.005564
Subject(s) - fields, waves and electromagnetics , engineered materials, dielectrics and plasmas
Aging of transformer paper insulation is commonly investigated through indirect measurements conducted in the oil, e.g. furanic compounds. In addition to the conventional indicators, recent investigations showed that alcohols like methanol and ethanol in oil could be used as paper aging indicators. This paper focuses on the applicability of these new paper aging indicators in a novel, gas-to-liquid (GTL) technology based transformer oil through an accelerated laboratory aging experiment. The experiment was conducted at 120 °C for up to 280 days. A conventional mineral oil was also tested as a reference. Kraft paper aged in both oil types showed similar reductions in degree of polymerization (DP) and tensile strength (TS). Amount of methanol in oil is higher than that of 2-FAL in oil when DP is over 375, confirming the promise of using methanol as an early paper aging indicator. Both the new paper aging indicator, methanol and the conventional paper aging indicator, 2-FAL are applicable for the GTL oil without any modifications. In addition, oil only aging experiments showed that oil does produce methanol but it is negligible compared with oil paper aging experiment; however the amount of ethanol measured in the present oil paper aging experiment is believed to be originated from oil oxidation rather than from paper aging.