Journal of Engineering Research

, 3:13

First online:

Open Access This content is freely available online to anyone, anywhere at any time.

Condition monitoring and fault diagnosis of an MR load tap changer using oil analysis data

  • H. MolaviAffiliated withNiroo Research Institute (NRI) Email author 
  • , A. ZahiriAffiliated withNiroo Research Institute (NRI)


Considering the objectives of “condition based preventative maintenance strategy”, condition monitoring and fault diagnosis of an MR M-type load tap changer (LTC) was assessed by applying several oil analysis techniques, followed by interpretation of the derived data. The interpretation revealed the oil low cleanliness level as well as in progress thermal fault with light coking or increased resistance of the contacts or severe arcing. As a result, overhauling and visual inspection were recommended in spite of the suggested overhaul criteria by the manufacturer, which advised no overall repair for the pilot LTC at that time.

Finally by overhauling the pilot LTC, the observations from physical inspection were compared to the extracted results from oil analyses data interpretation, which were in close agreement with each other.


Condition monitoring DGA fault diagnosis LTC: oil analysis