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The way to set is identical with 5.2.3
5.2.5. SEF Fault
SEF(Sensitive Earth Fault) fault is used when ground fault current is small in ungrounded
system. Next it is operation diagram about operation area. Like the picture, +-90° becomes
operation area by setting’s op-Angle. When earth current and voltage volume is over the
set value with a fault and earth current’s phase is in operation area based on earth
voltage, then it is picked up as fault. If this condition is kept during operation time, SEF
Fault is set.
To detect SEF Fault, setting items and ranges are like below.
<Table 5-3> Detecting Set Fault
Category Item Range Default Step Unit Explanation
Op Level
& Time
3I0 Pickup 0.1~20 5.0 0.1 A Set 3I0 current operation value
-3V0 Pickup 0~80 30 1 % Set 3V0 voltage operation value
SEF Reset Time 0.00~1.00 0.00 0.01 sec Set SEF reset time of definite time
Func In Use
OFF/ALARM/
TRIP
OFF Set SEF fault operation functions
Delay DT Level 25~10000 OFF 1 A Set operating value at delay DT level
Delay DT Time 0.01~2 2.00 0.01 sec Set operating time at delay DT time
HCT Level 25~10000 OFF 1 A
Set operating value at high current
trip level
HCT Time 0.01~1 0.04 0.01 sec
Set operating time at high current
trip time
Func In Use NO/YES YES Set phase fault operation functions
Block flt
Pickup
Cold Load Multi 1~10 2 1
A multiplier to prevent the
mis-recognizing as a fault by
increasing a multiply of pick-up level
under cold load condition.
Return Normal I 0~30 0.3 0.01 sec
Set the return current of restraining
operation against cold load
Cold Load Time 0~180 3 1 min Set restraining time of cold load
Use Cold Load NO/YES NO Set cold load Use/Not use
Inrush Multiply 1~10 2 1
A multiplier to prevent the
mis-recognizing as a fault by
increasing a multiple of pick-up level
under inrush condition
Inrush Time 0~30S 0.02 0.01 sec Set restraining time of Inrush
Use Inrush NO/YES NO Set inrush Use/Not use
2nd Harmonic 1-50 20 1 % A level of regarding 2
nd
harmonic as inrush
Use 2nd
Harmonic
0.02~1 0.02 0.01 sec Set 2
nd
harmonics Use/Not use
Fault
Direction
Trip Direction OFF/FWD/REV OFF Selection of ground fault direction
3V0 Threshold 0~100 20 1 % Set zero sequence voltage operating value
3I0 Threshold 0~100 20 1 % Set zero sequence current operating value
3I0 Angle 0~359 300 1 ° Set zero sequence current operating angle
Dir Block OC NO/YES NO Set direction function block