Feeder protection REF601:

 REF601 is a dedicated feeder protection relay, intended for the protection, measurement and supervision of utility substations and industrial power systems.   Engineered from the ground up, the relay is inspired by and is compatible with the Rogowski coil sensor for current measurement. The new feeder protection relay is designed to unleash the advantages of current sensors for protection and control in medium voltage applications.   -----> Protection Functions  REF601 offers three-stage overcurrent and two-stage earth-fault protection functions. The transformer inrush detector function is incorporated to prevent unwarranted trippings.  The low-set stages for overcurrent and earth-fault protection are equipped with selectable Definite-time (DT) and Inverse-Definite Minimum Time (IDMT) characteristics. The relay features standard IDMT characteristics – Normal Inverse (NI), Very Inverse (VI), Extremely Inverse (EI), Long-time Inverse (LI) and a special characteristic RI inverse (RI) for better co-ordination with rest of the network.  The table in figure  indicates the protection functions available in the relay.