Protection Function

Three Phase Current Protection

Functionality

The three-phase overcurrent protections is used as single-phase, two-phase

or three phase non-directional overcurrent and short-circuit protection for feeders.

The function starts when the current exceeds the set limit. 

The operate time characteristics for low stage is both DMT and IDMT and high stage is definite time (DT) definite minimum. 

The instantaneous stage always operates with the DT characteristic.

In the DT mode, the function operates after a predefined operate time and resets when the fault current disappears. 

The IDMT mode provides current-dependent timer characteristics.

Earth Fault Protection

Functionality

The earth-fault function is used as non-directional earth-fault protection for feeders.

The function starts and operates when the set current exceeds the set limit.

The relay can measure earth current by internal calculation (IEC variant only) and

also by external core balance current transformer input.

Separate earth fault input is available in relay which can be connected to corebalance current transformer of 1A secondary.

The operate time characteristic for low stage has both DT and IDMT and high stage has only

definite time (DT) .. In the DT mode, the function operates after a predefined

operate time and resets when the fault current disappears.