Setting Range Of Earth Fault Overcurrent Protection; Three Phase Inrush Detector - ABB REF601 Applications Manual

Section 4
Protection and Control Function
4.2.3
4.3
18

Setting range of Earth fault Overcurrent Protection

Table 7: Setting ranges Non-directional earth fault protection, Low stage Io>, 51N
Description
Nominal value of earth current
Setting range of pick-up current Io>
Operate time delay (DT) to>
Operating curve type (IDMT)
Time multiplier setting ko (IDMT)
Reset ratio
Reset time
Trig CBFP
Table 8: Setting ranges Non-directional earth fault protection, High stage Io>>, 50N
Description
Setting range of pick-up current 'Io>>'
Operation mode
Operate time delay (DMT)
'to >>'
Reset ratio
Reset time
Trig CBFP

Three Phase Inrush Detector

The transformer inrush detection is used to block overcurrent protection during
transformer inrush situations in distribution networks.
Transformer inrush detection is based on the ratio of 2
fundamental frequency. When an inrush case is detected, the phase overcurrent and
earth fault protection functions are immediately blocked.
Table 9: Setting ranges Transformer inrush detector
Description
Inrush threshold value
Ratio Setting
Value
1 A or 5A for CT variant, 1A for sensor variant
External earth :
0.01...2.0 x In in steps 0.001, infinite
Internal earth :
0.1...2.0 x In in steps 0.001, infinite
0.04...64 sec in steps of 0.01
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
0.02...1.6, in steps of 0.01
IDMT : 0.96 and DT : 0.98
40 Msec
Yes / No
Value
External earth:
0.05...12.5 x In in steps 0.001, infinite
Internal earth:
0.5...12.5 x In in steps 0.001, infinite
Definite time
0.04...64 sec in steps of 0.01
0.98
40 msec
Yes / No
nd
harmonic current and the
Value
0.2 ... 20 x In (Sensor Variant)
0.2 ... 25 x In (CT variant)
30%...50%
1MDU07212-YN Rev. C
REF601 / REJ601
Application Manual