A novel pilot protection scheme for transmission lines based on current distribution histograms and their Bhattacharyya coefficient

•The current characteristics at both ends of a transmission line are represented by probability distribution histograms.•The similarity of current distribution histograms is quantified by Bhattacharyya coefficient (BC) to form a novel pilot protection scheme.•The proposed scheme is applicable to faults accompanied with CT saturation, which may cause the malfunction of conventional protection scheme.•The proposed scheme has good robustness with respect to false pulse data, data loss, and white noise. The current waveform characteristics at both ends of a transmission line under different disturbances are represented by means of probability distribution histograms. By adopting the Bhattacharyya distance (BD) algorithm to quantify the similarity of current distribution histograms, a novel scheme of pilot protection for transmission lines based on Bhattacharyya coefficient (BC) is put forward. The proposed scheme can correctly identify internal faults, external faults, and faults accompanied with current transformer (CT) saturation of transmission lines. It also shows good performance in the cases of abnormal samples. The validity of the proposed scheme is evaluated by various simulation and dynamic analog experiment tests.