Short Circuit Protection of Circuits with Mixed Conductor Technologies in Transmission Networks

The TB gives all informations to compute series impedances, shunt admittances and sequence series impedances for overhead lines, underground cables and mixed conductor circuits. It also covers impedance calculation for internal faults in underground cables. Protection schemes to discriminate between faults in the underground cable section and faults in the overhead line section are described. Several solutions for transition equipments auxiliary supply are described and compared. Finally, emerging solutions allowing precise fault discrimination between sections avoiding the need for transition equipment are presented.