Current-only fault passage indicator for high impedance grounded networks

In this paper a novel algorithm for earth-fault passage indication in high-impedance grounded medium voltage networks is proposed. Given that the majority of secondary substations in medium voltage (MV) grids lack voltage measurements, the algorithm relies solely on current measurements. This feature significantly reduces the time required to identify faulty sections, thereby accelerating power restoration for all affected customers. Unlike other current-only methods, the proposed approach eliminates the need for estimating any fundamental or higher harmonic phasors. It is also resilient to false indications that can occur during post-fault transients or from unreliable phasor information during steady-state conditions – issues often influenced by the level of network compensation. The proposed method achieves robust and accurate fault passage indications through the utilization of transient signal components in short time intervals following fault inception. The algorithm's efficacy is validated using fault records from real-world power networks.