A Traveling-Wave-Based Protection Technique Using Wavelet/PCA Analysis

This paper proposes a powerful high-speed traveling-wave-based technique for the protection of power transmission lines. The proposed technique uses principal component analysis to identify the dominant pattern of the signals preprocessed by wavelet transform. The proposed protection algorithm presents a discriminating method based on the polarity, magnitude, and time interval between the detected traveling waves at the relay location. A supplemental algorithm consisting of a high-set overcurrent relay as well as an impedance-based relay is also proposed. This is done to overcome the well-known shortcomings of traveling-wave-based protection techniques for the detection of very close-in faults and single-phase-to-ground faults occurring at small voltage magnitudes. The proposed technique is evaluated for the protection of a two-terminal transmission line. Extensive simulation studies using PSCAD/EMTDC software indicate that the proposed approach is reliable for rapid and correct identification of various fault cases. It identifies most of the internal faults very rapidly in less than 2 ms. In addition, the proposed technique presents high noise immunity.