In this paper, application of alienation technique has been presented for fault analysis on three-terminal transmission line system. For evaluation of Alienation Coefficients, samples of post-fault differential current (of successive cycles), are compared, for a quarter cycle window. This Alienation Coefficient is compared with the threshold, to detect and classify the faults. The proposed protection scheme is able to detect and classify the faults, within quarter-cycle. The performance of the proposed scheme has been established by case studies, in which fault locations, incipient angles and impedances are varied. © 2018 IEEE.