A Wavelet-Based Transformer Differential Protection: Internal Fault Detection During Inrush Conditions

This paper proposes the boundary discrete wavelet transform-based differential protection for detecting internal faults during inrush conditions in order to enhance both the safety and reliability of the differential relay during transformer energizations. The proposed method was assessed by using representative simulations of transformer energizations (with and without internal faults) as well as sympathetic inrush conditions. The performance of the proposed method was compared with a conventional technique and a wavelet-based scheme, and good results were obtained.