A phase-shifting transformer can effectively regulate the flow of electricity, and it is essential to equip it with high-performance protection devices to ensure the safe and reliable operation of the power system. Taking a 35 kV single-core symmetrical phase-shifting transformer as the research object, this paper proposes a corresponding protection scheme for the transformer. First, the operating characteristics of the transformer are analyzed based on Kirchhoff’s current law and the law of electromagnetic induction. Then, based on its topological structure, the installation position of the protection current transformer is designed, and electrical and magnetic balance differential protection schemes are constructed. This scheme can cover the internal phase-to-phase faults and winding-to-winding faults of each winding and the winding lead of the single-core phase-shifting transformer. Finally, a single-core phase-shifting transformer model is built on the Matlab/Simulink platform by setting up typical faults within the transformer body, and the validity of the two differential protection configuration schemes proposed is verified.