Feeder protection and control / Feeder protection
14 ABB
18. Protection functions
Table 23. Low-set phase overcurrent protection, stage 3I> / 51
Setting range of pick-up current ‘I >’
0.5...2.5 x In in steps 0.001, infinite
± 5.0% of set value, ± 10.0% of set value for set value < 0.2
Operate time delay (DMT) ‘t >’
0.04...64 s in steps of 0.01
1.2 x setting of pick-up current “I >”
± 5.0% of set value or ± 30 ms
IEC 60255-3:
Normal inverse, Very inverse, Extremely inverse, Long-time inverse
ANSI C37.112:
Moderate inverse, Normal Inverse, Very inverse, Extremely inverse
Special curves: RI inverse
Time multiplier setting ‘k’
0.02...1.6, in steps of 0.01
Operation time accuracy
IEC and ANSI characteristics
RI characteristics
class E(5) or ± 30 ms, class E(7.5) or ± 30 ms for set value < 0.2
± 5.0% of set value or ± 30 ms
IDMT : 0.96 and DT : 0.98
Table 24. High-set phase overcurrent protection, stage 3I>> / 50-1
Setting range of pick-up current ‘I>>’
0.5...25.0 x In in steps 0.001, infinite
Definite time, Instantaneous
Operate time delay (DMT) ‘t >>’
0.04...64 s in steps of 0.01
± 5.0% of set value or ± 30 ms
Table 25. Very high-set phase overcurrent protection, stage 3I>>> / 50-2
Setting range of pick-up current ‘I>>’
0.5...25.0 x In in steps 0.001, infinite
Definite time, Instantaneous
Operate time delay (DMT) ‘t >>>’
0.03...64 s in steps of 0.01
± 5.0% of set value or ± 15 ms