Prevention of Malfunctions in Differential Protection of Power Transformers Using Digital Twin Technology

During the energization of transformers, the prevalent method for configuring the differential protection blocking logic involves setting it based on the second-harmonic content of magnetizing inrush. The protection IED can mal-operate as the second-harmonic content decreases during the magnetizing inrush in modern transformers. This paper presents a method for preventing the maloperation of differential protection by estimating the second-harmonic content using Digital Twin. In this study, the potential second-harmonic content from determined transformer conditions is estimated using Digital Twins. Comparative analyses under various conditions are provided through PSCAD simulations. Finally, based on the results of PSCAD simulations performed on transformers with different initial characteristics, a method is proposed to prevent maloperation of differential protection through the estimation of second-harmonic content.