Sympathetic Inrush Identification Based on Features of Exponential Component in Differential Current

When the core of a power transformer enters saturation region, inrush will occur and result in results in the increase of differential current and may cause protection relay to malfunction. In order to prevent transformer protection relay from malfunctioning, this paper proposes a method for sympathetic inrush identification based on the trend of the exponential component extracted by using morphological transform (MT). Simulation studies is conducted using PSCAD/EMTDC to verify the feasibility of the proposed method. Simulation results show that the proposed method is adaptable to different conditions even if current transformer (CT) is severely saturated.