Alireza Zahiri - Researcher in Chemistry and Material Center, NRI
Hoda Molavi - Assistant Professor in Chemistry and Material Center, NRI

Due to the critical role of on load tap changers (OLTCs) in electrical network, it is essential to choose condition based preventative maintenance strategy in order toreach the aims such as reduction in costs, the number of unnecessary visits as well as the probability of interruptions and also increment in equipment reliability. Considering the mentioned objectives, condition assessment was performed over an MR M-type load tap changer using oil analyses includingmeasurement of breakdown voltage, dissolved gas analysis as well as analyses of dissolved metals and suspended particles in oil.

Condition Assessment, Oil Analysis, On Load Tap Changer