IERE joint R&D project

Methanol Ageing Marker forPower Transformers (phase 2)
Post-Mortem Sampling for Degree of Polymerization
Deterioration Modelling

June 2023

Background• METHANOL: In recent years, analyzing the methanol content in transformer oil has been identified

as an adequate ageing marker that aids significantly the insulation winding paper diagnostic andthus the transformer end-of-life estimation. Field experiences have shown that the implementation of
the classical furan testing only appears not adequate enough for assessing winding paper ageing ofmany types of power transformers. The benefits of implementing methanol instead of or incombination with furans are especially for transformers with thermally upgraded paper or using
inhibited transformer oil or with sealed atmospheric protection systems. Also evaluating prematurewinding paper ageing is more adequate using methanol compared to furans based on ‘IERE
methanol phase 1’ study.
• PHASE 1: From 2012-2016, IERE instigated and hosted an international joint R&D project tointroduce and trial the use of methanol as an ageing marker for power transformers. This multi-year
project concluded the presence of methanol in aged transformers under different climates asobserved by different utilities and companies.
• DP & POST-MORTEM ANALYSIS: To ascertain direct correlation between the methanol
concentration with respect to the level of degradation or ageing of insulation materials, the mostappropriate, necessary and reliable way is to examine the Degree of Polymerization (DP) of
the insulation papers in the old/retired transformers. This requires post-mortem analysis of insulationmaterials in these transformers.
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ObjectiveThe objective of the proposed Joint R&D project phase 2 is to analyze a collection of specific winding
insulation paper material extracted during post-mortem dismantling of selected power transformers andto establish a robust degradation model by correlating the concentrations of temperature-corrected
methanol-in-oil with the real winding paper degradation.

Benefits
This project phase 2 will enable the development of a universal model and associated guidelines in using
methanol as an ageing marker for power transformers, leading to a complimentary and preventive means
to existing methods. Joining experts and efforts of different large power utilities, network operators, …
during this multi-year project will allow to gather enough specific post-mortem paper samples to havesufficient data to build this ageing model.

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ScopeActive-participants (IERE member, IERE non-member)Specific sampling methods (methanol, paper)
Analysis results

Paper samples
Oil samples
Historical transformer O&M data

ENGIE Laborelec (leader)• Dismantling reports• Coordination technical meetings• Full report (incl. Ageing Model)(Purchase possible after the project)
NON Active-participants (IERE member, IERE non-member)
4Duration & Technical meetings• Duration: 2019–2023 (Extended for one year to the end of 2023)• Technical meetings:
May 2019:
Kick-off meeting (Daejeon, Korea)
Jun. 2021:
Technical meeting 1 (online)
Oct. 2023:
Technical meeting 2 (Tokyo, Japan)

Active-participants (as of Dec. 2020)(leader)5

Project costs• An upfront charge of 30,000 USD payable to ENGIE Laborelec per Active IERE Member participant• An upfront charge of 40,000 USD payable to ENGIE Laborelec per Active IERE NON-Memberparticipant
If a non-active IERE-member wishes to receive a copy of the full report including the detailed ageing
model, it shall pay the amount of 45,000 USD to IERE. A non-IERE member can also buy the full report
but for the amount of 60,000 USD.

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