Terms of Reference

A significant number of transformers and shunt reactors in service are reaching or have already exceeded their expected end of life. Thus, transformer and shunt reactor users are dealing with an ageing population and have to plan a reinvestment program. Information on the condition of the solid insulation of these apparatus can be used as a key parameter for:- Condition assessment of a transformer and shunt reactor fleet- Selection of the best reinvestment option: repair/refurbish/replace When transformers and shunt reactors have to be repaired, refurbished or scrapped/replaced, windings often have to be dismantled, which allows having access to critical parts of solid insulation that are usually not accessible. Thus, the correlation between paper condition and ageing markers (measured in the oil) can be evaluated. Moreover, in order to apply more accurately ageing markers and transformer and shunt reactor ageing models, there is a need to obtain design information e.g. quantities of oil and solid insulation (paper and board). Knowing that the quantity of insulating materials is directly linked to the design, the use of ageing markers models should be significantly improved by comparing their concentrations dissolved in oil with the quantity and the nature of the materials implied. Scope: This WG will compare the existing ageing markers with practical measurements of degree o