Protection functions 

The REF601 and REJ601 offer three-stage overcurrent and twostage ground-fault protection functions. 

The transformer inrush detector function is incorporated to prevent unwanted tripping due to energizing of transformers.

The REF601 and REJ601 offer three-stage overcurrent and 

two-stage ground fault protection functions. 

The low-set stages for overcurrent and ground fault protection are equipped with 

selectable characteristics – Definite Time (DT) and Inverse Definite Minimum Time (IDMT). 

The relays feature standard IDMT characteristics according IEC 61255-3 – Normal Inverse, Very 

Inverse, Extremely Inverse, Long-time Inverse. 

They also feature characteristics according to ANSI C37.112 – Moderate Inverse, 

Normal Inverse, Very Inverse, and Extremely Inverse. 

The relays also have a special characteristic RI Inverse (RI) for better coordination with the rest of the network. 

Additionally the relays also support two setting groups.

The REF601 and REJ601 also offer thermal overload protection for feeders, cables and transformers. 

Other protections include negative phase sequence protection, phase discontinuity 

protection and circuit breaker failure protection. 

The relays also have an auto-recloser option for overhead line feeders.