Section 6 1MRK 505 353-UEN
BP-Additions to base documentation
44 Application Manual
Bay protection functions REB500
Table 51 Inverse time earthfault overcurrent protection 51N (PTOC)
Function/ Parameter Range/ Value
Inverse time characteristic
(acc. to B.S. 142, IEC 60255-3 with extended setting range):
• normal inverse
• very inverse
• extremely inverse
• long time inverse
t = k
1
/ ((I/I
B
)
C
- 1)
• c = 0.02
• c = 1
• c = 2
• c = 1
• or RXIDG characteristic
t = 5.8 - 1.35 x·ln(I/I
B
)
• Number of phases
1 or 3
• Base current I
B
0.04 to 2.5 I
N
in steps of 0.01 I
N
• Pick-up current I
start
1 to 4 I
B
in steps of 0.01 I
B
• Min. time setting t
min
0 to 10 s in steps of 0.1 s
• k
1
setting
0.01 to 200 s in steps of 0.01 s
• Response time without delay
60 ms
· Neutral current measurement (derived externally or internally)
· 4 independent parameter sets
Table 52 Peak value over and undercurrent protection 50 (PTOC/PTUC)
Function/ Parameter Range/ Value
• Current
0.1 to 20 I
N
in steps of 0.1 I
N
• Delay 0 to 60 s in steps of 0.01s
• Max. trip time with no delay (at f
N
) for max. function
• Max. trip time with no delay (at f
N
) for min. function
£30 ms
£60 ms
· Maximum or minimum function (over- and undercurrent)
· Single or three-phase measurements
· Wide frequency range (0.04 to 1.2 f
N
)
· Peak value evaluation
Accuracies Value
Accuracy of the pick-up value (at 0.2 to 1.1 f
N
)
±5%
• Reset ratio for max. function
• Reset ratio for min. function
• >90%
• <110%
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