Application 

The REF601 and REJ601 are protection relays aimed at protection and control of incoming and outgoing feeders in MV distribution substations. 

They can be applied for short-circuit, overcurrent and ground-fault protection of 

overhead lines and cable feeders of distribution and sub-distribution networks.

The inrush current stabilization function allows the relays to be 

used as the main protection for distribution transformers.

The relay with application configuration B offers non-directional 

overcurrent and ground-fault protection. The residual current for 

the ground-fault protection is derived from the phase currents. 

When applicable, core-balance current transformers can be 

used for measuring the residual current, especially when sensitive ground-fault protection is required.

The application configuration C adds thermal overload protection for feeders, cables and transformers, phase discontinuity 

protection and circuit breaker failure protection.

The application configuration D provides the highest functionality with incorporation of negative 

phase sequence protection and a multi-shot auto-recloser function making the relay suitable for overhead line feeders.

Optimized for limited space

With their compact size and unique technical features, the 

REF601 and REJ601 are ideal for retrofits, compact switchgear 

and switchgear with limited space. These relays have a small 

mounting depth and do not have any loose mounting accessories. 

Uniquely, the REF601 and REJ601 use a press-fit mounting 

arrangement, suitable for quick and easy installation on switchgear

Control 

The REF601 features control of one circuit breaker with dedicated push-buttons and guidance on local HMI for opening and closing. 

It includes two dedicated outputs for breaker control. 

The breaker control is also possible through optional MODBUS RTU or IEC 60870-5-103 communication.