DCS/PLC module PFTL101A 0.5KN 3BSE004172R1

DCS/PLC module PFTL101A 0.5KN 3BSE004172R1

DCS/PLC module PFTL101A 0.5KN 3BSE004172R1

Zone 3 distance elements must be set according to the following criteria where possible:

• Zone 3 should overreach the remote terminal of the longest adjacent line by an acceptable margin (typically 20% of highest impedance seen) for all fault conditions and in feed conditions associated with all intended modes of system operation

• Zone 3 reach should be less than the zone 2 protection coverage of the shortest adjacent transmission circuit, and it should not see through power transformers into distribution systems in order to minimize the required zone 3 time delay setting. 7.4.3.5 Setting of overreaching zone The first overreaching zone (normally zone 2) must detect faults on the whole protected line.

Considering the different errors that might influence the measurement in the same way as for zone 1, it is necessary to increase the reach of the overreaching zone to at least 120% of the protected line. The zone 2 reach can be even higher if the fault infeed from adjacent lines at remote end is considerable higher than the fault current at the IED location. The setting shall generally not exceed 80% of the following impedances:

The impedance corresponding to the protected line, plus the first zone reach of the shortest adjacent line.

• The impedance corresponding to the protected line, plus the impedance of the maximum number of transformers operating in parallel on the bus at the remote end of the protected line.