Applicability of methanol as new marker for paper degradation in power transformers

This study was designed to examine methanol as a new aging marker of insulating paper. An analytical GC-MS method coupled to headspace injection was developed, followed by a validation. To further validate the possible applicability of methanol for different transformer conditions some laboratory studies were performed such as a stability and an aging test. Oil samples of power transformers of several Belgian nuclear and coal-fired power plants have been analyzed since mid 2009 and are followed-up periodically to correlate the results with the analysis of the furanic compounds which have been used since mid 1980s as oil soluble degradation products of the insulating winding paper. It seemed that while no 2FAL was present some considerable amount of MeOH was detected which revealed some paper degradation. A second real case study was started to further correlate MeOH and 2FAL results. From these laboratory and real case studies it seemed that MeOH is a very promising marker for paper degradation in power transformers.