Studying the Novel Interaction of Carbon Dots with Aged Mineral Oil Through Photoluminescence Emission

Carbon dots have covered a wide range of applications recently since they are biocompatible, non-toxic, and created in a low-cost hydrothermal process. Their size affects their photoluminescence properties which are determined by the specified conditions in the synthesis process. Photoluminescence spectroscopy is far less used than ultraviolet visible spectroscopy in the literature concerning condition assessment of power transformer insulating oil. This paper focuses on the development of a compatible optical sensor from carbon dots to assess the condition of aged mineral oil. The aged oil simulates the naturally occurring accelerated oxidation in an in-service power transformer according to ASTM D1934. During this, the novel interaction between the novel synthesized carbon dots and the mineral oil whether fresh or aged will be highlighted. Dielectric dissipation factor is obtained in the lab and correlated with the optical emission spectra of the novel optical sensor. Judging the oil condition is done by referencing the in-service limits of dielectric dissipation factor for mineral oil in power transformer specified in IEEE Std C57.106-2015. A novel optical sensor is developed from carbon dots capable of indicating dielectric dissipation factor and aging of the mineral oil under conditions that simulate real operation.