EHV transmission line protection using a morphological lifting scheme

This paper presents a novel algorithm for ultra-high-speed (UHS) protection relays of extra high voltage (EHV) transmission lines, using a morphological lifting scheme (MLS). The MLS focuses on identifying the gradient of the wavefront of a traveling wave contaminated by noise. The proposed algorithm can be used for either transient positional or directional protection. It is evaluated through a variety of simulation studies which are carried out on a typical 400 kV EHV transmission system model using the power simulation program PSCAD/EMTDC. The simulation results show that, with the MLS used, the algorithm is capable of providing accurate responses under various fault conditions in comparison with previous algorithms, such as wavelet transform (WT).