Using structured laser illumination planar imaging (SLIPI) as a new technique to monitor the degradation of biodegradable oils in electrical power transformers

The aging process of the insulating oils of an electrical transformer is initiated as soon as the transformer is put into service. The quality of these oils must therefore be rigorously evaluated to have reliable and exploitable data for decision-making. In general, the decision is to continue monitoring, reclaiming/regenerating, or replacing the oil in extreme cases. Thus, early diagnosis of power transformer oils helps prevent potential breakdowns that could considerably impact the electrical energy transmission and distribution network. This research used an imaging technique called SLIPI (Structured Laser Illumination Planar Imaging) to accurately determine the extinction coefficient in different samples of optically dense biodegradable oils (natural and synthetic esters). The variation in the extinction coefficient as a function of the aging of these biodegradable oils under test has been investigated. The results indicate that the SLIPI is reliable as a diagnostic tool for biodegradable oils in power transformers. This technique could therefore be an alternative solution to the conventional monitoring methods.