Time-domain application of superimposed quantities in the phase comparison transmission line protection scheme

Here, the use of incremental currents in time-domain phase comparison (PC) line protection schemes is evaluated. The incremental currents have been applied in modern high-speed protection relays, showing to be suitable for protection functions based on time-domain analysis. To carry out the proposed studies, the alternative transients programme was used to simulate a wide variety of fault scenarios in a 500kV/60Hz test power system, considering different fault features (distance, resistance, and inception angle), source-to-line impedance ratio values, and system loading conditions. In each case, the tripping times of the time-domain PC protection when implemented using traditional phase currents, sequence currents, traditional incremental currents, and incremental replica currents are compared. The obtained results show the use of incremental currents improves the PC protection reliability, speeding up the protection operation times.