A real-time DWT and traveling waves-based multi-functional scheme for transmission line protection reinforcement

This paper presents a multifunctional scheme to reinforce the protection of Extra High Voltage (EHV)/Ultra High Voltage (UHV) transmission lines. The proposed scheme employs d – q transformed traveling waves and the time of incidence of first traveling waves at both ends of the line for fault detection and location respectively. Furthermore, the faults are classified using energy values of approximation coefficients and the phasors are estimated from the approximation coefficients. The traveling waves are nothing but detail coefficients. The detail and approximation coefficients are obtained using discrete wavelet transform multi-resolution analysis (DWT-MRA) of the 3- ɸ current signals. The proposed algorithm detects and locates a fault within a quarter cycle. The proposed scheme has been implemented on a two-bus and the WSCC-9 bus systems in EMTDC/PSCAD software to verify the efficacy and reliability. Also, it has been realized on a laboratory model of an EHV transmission line of length 200 km using NI cDAQ-9178 chassis, NI-9227 current sensor card, and LabVIEW software. The simulation and hardware results evince the protection reinforcing property of the proposed multifunctional scheme.