ABB 1MDU07204-YNE Protection Function Feeder Protection REF601

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.

Principle of Operation

The three-phase overcurrent unit continuously measures the phase currents of the protected object. 

On detection of a fault the relay starts, trips the circuit breaker, records fault data etc. in accordance with the application.

REF601 has overcurrent protection with low set, high set and very high set module.

The product support both DMT and IDMT times in low set (I>) while high set (I>>) and Very high set (I>>>) supports to DMT timings. 

As the fault current exceeds the set value, trip time counting is started and start LED on front panel of relay glows ON. 

If fault current falls down below the drop off value of set current for 40 ms before trip time gets complete, start LED

will be turned off and trip count will become zero. 

Trip time will start from zero for next time when the fault current exceeds the set value again.

After a healthy trip, Start LED will be turned off and again if fault current exceeds threshold, start LED will be turned ON again.

In case of healthy trip, after trip time get elapsed relay generates the trip command which operates the Trip relay contacts as per user selected

configuration. Two LED indications on front plate of relay i.e. Trip (common trip indication) and Trip Ip and one signaling contact (XK2.3 –

XK2.4) will also be activated for user as Trip indication.

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.

Principle of Operation

REF601 has earth fault protection with low set and high set module.

Earth fault modules operate the protection as soon as fault current exceeds the set value of current.

It supports both DMT and IDMT timing while highset supports to DMT timings.

As the fault current exceeds the set value, trip time counting is started and start LED on front panel of relay glows ON.

If fault current falls down below the drop-off value of set current for 40 ms before trip time gets complete,

start LED will be turned off and trip count will become zero.

Trip time will start from zero next time when the fault current exceeds the set value again.

After a healthy trip, Start LED will be turned off and again

if fault current exceeds threshold, start LED will be turned ON again.

In case of healthy fault generation, after trip time get elapsed relay generates the trip

command which operates the Trip relay contacts as per user selected configuration.

Two LED indications on front plate of relay i.e.

Trip (common trip indication) and Trip Io and one signaling contact (XK2.1 –XK2.2) will

also be generated for user as Trip indication.