Application

The REJ603 is a protection relay aimed at selective short-circuit and earth-fault protection

of feeders in secondary distribution networks and for protection of transformers in utilities and industries.

The inrush current stabilization function allows the relay to be used as main protection of

distribution transformers.

The relay is powered up through current transformer if current is above energizing level of

relay, front USB power or through auxiliary supply (optional feature).

The relay offers, non-directional over current and earth-fault protection. 

The residual current for the earth-fault protection is derived from the phase currents. 

When applicable,the corebalance current transformers can be used for measuring the residual current,

especially when sensitive earth-fault protection is required.

The relay additionally offers thermal overload protection for feeders, cables and transformers.

There is optional provision of remote trip through binary input with external auxiliary power supply.

The remote trip signals like transformer trouble output (Buchholz, Oil temperature,

Winding temperature trip) or an external trip can be wired

to binary input. The remote trip function works even in CT-powered mode when auxiliary supply

is not available but enough CT current is available to power-up the relay.