ABB REF615 relay configuration(CT ratio)

REF615 is a dedicated feeder protection and control relay for protection, control, measurement and supervision of overhead lines and cable feeders in utility and industrial power distribution systems, including radial, looped and meshed distribution networks, with or without distributed power generation. REF615 has been designed to be the main overcurrent and earth-fault protection for overhead lines and cable feeders, in either isolated neutral, resistance-earthed, compensated or effectively-earthed distribution networks, depending on the standard configuration. REF615 is available in altogether twelve standard configurations, of which two provide maximum functionality to allow fully flexible tailoring, one for sensors and the other for conventional current transformers. The extensive earth-fault protection portfolio has been expanded to include a unique multifrequency admittance-based protection for higher sensitivity and selectivity. The new earth-fault protection is...