Self-powered feeder protection
14 ABB
Table 24. Very high-set phase overcurrent protection, stage I>>> / 50-2
Setting range of pick-up current ‘I >>>’
0.2...32.0 x In in steps 0.001, infinite for CT variant
± 3.0% x In for value < 1.2 In , ± 3.0% x I for value ≥ 1.2 In
Definite time, Instantaneous
Operate time delay (DMT) ‘t >>>’
0.04...64 s in steps of 0.01
Operation time accuracy
1)
± 2.0% of set value or ± 30 ms
1)
Operation time accuracy for protection functions when relay is in energised condition.
Table 25. Low-set earth-fault protection, stage I0> / 51N
Setting range of pick-up current ‘I0 >’
External earth measurement (through CBCT or residual connection) :
0.01...2.0 x In in steps 0.01, infinite
Internal earth measurement : 0.1...2.0 x In in steps 0.01, infinite
External earth measurement : ± 3.0% x In for value < 1.2 In ,
± 3.0% x I for value ≥ 1.2 In
Internal earth measurement : ± 9.0% x In for value < 1.2 In ,
± 9.0% x I for value ≥ 1.2 In
Operate time delay (DMT) ‘t0 >’
0.04...64 s in steps of 0.01
Operation time accuracy
1)
External earth measurement : ± 2.0% of set value or ± 30 ms
Internal earth measurement : ± 10.0% of set value or ± 30 ms
IEC 60255-151:
Normal inverse, Very inverse, Extremely inverse, Long-time inverse
ANSI C37.112:
Moderate inverse, Normal Inverse, Very inverse, Extremely inverse
Special curves:
RI inverse, HR fuse, FR fuse
Time multiplier setting ‘k0’
0.02...1.6, in steps of 0.01
Operation time accuracy
1)
IEC, ANSI, HR, FR characteristics
RI characteristics
IEC, ANSI, HR, FR characteristics
RI characteristics
External earth measurement : class E(5) or ± 30 ms
External earth measurement : class E(7.5) or ± 30 ms
Internal earth measurement : ± 5.0% of set value or ± 30 ms
Internal earth measurement : ± 10.0% of set value or ± 30 ms
IDMT : 0.96 and DT : 0.98
1)
Operation time accuracy for protection functions when relay is in energised condition.
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