A Portable, Non-Invasive and Non-Destructive Technique for Condition Assessment of Liquid Insulation

Liquid insulation plays a vital role as an insulant and coolant in transformers. It provides detailed information about the condition of the transformers. Numerous testing methodologies and equipment are available to evaluate the physiochemical and electrical properties of the liquid insulation. In their previous work, the authors presented a non-invasive and non-destructive technique for condition assessment of mineral oil. This work focuses on making the technique portable and extending it to alternate insulating oils such as nanofluids, ester, and blended oils. It also discusses the limitations of its application to nanofluids. The average errors in the prediction of moisture and acid number for blended oils are found to be
$11.53{\rm{\% }}$
and
$3.26{\rm{\% }}$
, respectively. This handy, portable and fast condition assessment module for insulating oils will be helpful for utilities in on-site testing.