Evaluation of a New Current Directional Protection Technique Using Field Data

A novel current polarized directional element technique to determine the fault direction on a transmission line is evaluated using fault data recorded in the field. The post-fault current signal and a directional reference current signal are used. A directional current element is derived from these quantities. The directional normal power flow before fault occurrence is also used. The voltage signal is excluded from the study after fault occurrence. Test results show that the new technique is not affected by the system operating parameters. The technique has a high degree reliability, selectivity and stability for a majority of practically encountered problems.