An assessment of the potential for oil flow damage in Kraft paper under normal operation and reclamation in a high voltage transformer

Thermal aging and UV irradiation are used as methods to prepare samples of Kraft paper spanning its full lifecycle within a high voltage transformer, from new to end of life. The mechanical break strain is correlated to the DP value, representing a progressive deterioration of mechanical properties during aging. Subsequent exposure to oil flow mimicking both normal plant operation and reclamation activities, shows that aged paper exposed to high rates of flow experiences noticeable surface roughening. Despite this, no measurable erosion occurs even after long term temperature/flow cycling in used mineral oil containing a notable particulate content. This indicates that Kraft paper is unlikely to be eroded by normal reclamation activities, even in a severely aged asset. This confirms the validity of using this approach to extend plant life