New broad range mode earth fault protection from Arcteq

The increased medium voltage cabling, distributed power generation and compensated networks (Petersen coil), has led to new challenges in earth-fault protection of distribution feeders. Relying on conventional protection methods may lead to either nuisance trips of healthy feeders or undetected faults in faulty feeders.

To meet the new network requirements 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 (see figure on left). 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 overhead lines.

 

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