Compatibility of mineral insulating oil with transformer construction materials

This study is focused on the determining the compatibility of mineral insulating oil with various transformer materials obtained from transformer manufacturers. For this study, traditional chemical methods, in accordance with the requirements of the IEC 60422 standard (See Table 3), were applied. The effects of the various transformer materials - such as epoxide, polyurethane, cyanoacrylate, polyvinyl alcohol (PVA) adhesives and an epoxy reinforcing bar on the oil's properties were determined. The findings were evaluated by means of the sensitivity of individual methods to any changes in the oil's properties caused by the transformer materials. Furthermore, the oil's properties were evaluated according to the requirements of the ASTM D3455-11 standard, and some tested materials were excluded. The aim of the study was to reveal which materials are most compatible with the oil. This insight could be of great interest to transformer manufacturers, as it was shown that some materials could considerably affect the oil's properties.