The requirements for the distribution network management are changing rapidly. Underground cabling and distribution automation is implemented in distribution networks to increase network reliability. Cabling also increases earth-fault currents. To achieve safer network operation and to further increase the reliability, compensated networks are ever more common in all around the world. Despite the numerous benefits of compensated networks, until today locating earth faults in such sophisticated systems has been a challenge.
This paper describes a novel algorithm for feeder earth-fault protection applicable in compensated and unearthed medium-voltage networks. The results show that the novel algorithm provides universal, all-in-one protection function that detects selectively all types of earth faults.
The paper was first published at CIRED 2014.