The increase of medium voltage cabling, connection of distributed generation and compensated networks (Petersen coil) along with distributed compensation has led to new challenges in earth-fault protection of distribution feeders.

Arcteq has developed a new broad range mode with multi-criteria detection that handles earth fault situations in both isolated and compensated networks, without need to make changes to the settings of the protection relays. The new algorithm combines sample based (3,2 kHz) and symmetrical component calculation. The multi-criterion based method also improves detection of earth faults in networks with distributed compensation and with a combination of cables and over head lines.

Read more about the new solution from our latest application note.


Figure 1 Traditional directional earth-fault protection modes

Figure 2 Operation of new broad range mode covers both ungrounded and compensated
networks and is equipped with optional, additional multi-criteria detection for compensated
networks to increase the protection sensitivity