Lifetime estimation of vegetable oil for transformers

Abstract

In this paper the results of an experimental study concerning the vegetable oil's (subjected to thermal ageing) lifetime estimation based on the activation energy and IEC 60216-1/2001 methods are presented. Three accelerated thermal ageing tests were performed on transformer vegetable oil samples at 135, 155 and 175 °C. The lifetime curves were drawn for three diagnostic factors, namely loss factor, conductivity and total acid number. Using DSC (Differential Scanning Calorimetry) method, the activation energy corresponding to the oxidation reaction has been determined. Subsequently, using the results of thermal ageing at 175 °C, the lifetime curves have been drawn. It is concluded that the activation energy method is quicker and less expensive therefore it could be useful to obtain new information about a new vegetable oil for paper/oil insulations.

Use of vegetable oils as transformer oils – a review

“…The major technical areas (with respect to the use of vegetable oils as insulation liquid in transformers), which need further attention is listed as following [5,[42][43][44][45][66][67][68][69][70][71][72][73][74][75][76][77][78][79][80][81][82][83][84][85]: (i) More studies and research is needed to the reduce the production cost, develop low cost feed stocks and identify potential markets in order to balance cost and availability. (ii) Continued transformer performance and durability in a variety of transformer types and sizes need to be developed to increase manufacture and consumer confidence.…”

“…The major challenges that face the use of vegetable oil as transformer oil are listed as follows [1,42,[66][67][68][69][70][71][72][73][74][75][76][77][78]:…”