Sympathetic inrush is a phenomenon that occurs in an in-service transformer (IT) when a nearby transformer is energized. The phenomenon can cause transformer differential protection to maloperate. Identification methods for sympathetic inrush have been proposed to deal with the problem. However, these methods are based on local information from the IT, while sympathetic inrush involves two or more transformers. Therefore, an identification method is proposed based on substation-area information. A substation-area differential current is defined and its second harmonic component is utilized to identify the sympathetic inrush. Simulation results by PSCAD/EMTDC show the proposed method can distinguish sympathetic inrush from internal faults and energization inrush effectively.

differential protection,magnetizing inrush,substation-area information,sympathetic inrush,transformer protection