Detection, classification, and location of faults in power transmission lines

Selective scaling (a) the whole frequency spectrum (b) frequency components after selective scaling. The frequency components selected belong to the harmonics of a particular fundamental frequency (c) Discrete S-Transform complex matrix representation only the darkened portion needs to be computed. [Display omitted] •A novel Fast Discrete S-Transform is presented for differential and impedance protection.•The new variant provides fast fault classification and location using frequency filtering.•Spectral energy changes can be calculated in real time.•Effects of several parameters are also discussed. This paper presents a pattern recognition approach for current differential relaying of power transmission lines. The current differential method uses spectral energy information provided through a new Fast Discrete S-Transform (FDST). Unlike the conventional S-Transform (ST) technique the new one uses different types of frequency scaling, band pass filtering, and interpolation techniques to reduce the computational cost and remove redundant information. Further due to its low computational complexity, the new algorithm is suitable for real-time implementation. The proposed scheme is evaluated for current differential protection of a transmission line fed from both ends for a variety of faults, fault resistance, inception angles, and significant noise in the signal using computer simulation studies. Also the fundamental amplitude and phase angle of the two end currents and one end voltage are computed with the help of the new formulation to provide fault location with significant accuracy. The results obtained from the exhaustive computation show the feasibility of the new approach.