Relationship between static electrification of transformer oils with turbidity and spectrophotometry measurements.

Highlights: [•] Electrostatic charging tendency of fresh and aged oils were investigated in a spinning disk system. [•] The electrification currents were related to classical aging indexes. [•] Two testing procedures developed by ASTM were used to monitor decay products as trace impurities. [•] The electrification currents increase with temperature, fluid velocity and disk properties. [•] The electrification is definitely related to turbidity and spectrophotometry measurements. [ABSTRACT FROM AUTHOR]