ABB 22
1MAC251744 -PG Rev. A
Issued: 03.01.2010
Motor Protection
REM615 ANSI
Product Version 2.0
Table 30.Directional ground fault protection (67/51N)
Characteristic Value
Pickup
accuracy
Depending on the frequency of the current meas-
ured: f
n
±2Hz
67/51N
Current:
±1.5% of the set value or ±0.002 x I
n
Vo l t a g e :
±1.5% of the set value or ±0.002 x U
n
Phase angle:
±2°
Pickup time
1) 2)
Minimum Typical Maximum
67/51N:
I
Fault
= 2 x set Pickup range
61 ms 64 ms 66 ms
Reset time < 40 ms
Reset ratio Typical 0.96
Retardation time < 30 ms
Trip time accuracy in de nite time mode ±1.0% of the set value or ±20 ms
Trip time accuracy in inverse time mode ±5.0% of the theoretical value or ±20 ms
3)
Suppression of harmonics RMS: No suppression DFT: -50dB at f =
n x f
n
, where n = 2, 3, 4, 5,…
Peak-to-Peak: No suppression
1)
Set De nite time delay = 0,06 s, Inverse-time (IDMT) and de nite-time (DT) curves = IEC de nite time, Measurement mode = default
(depends on stage), current before fault = 0.0 x In, fn = 50 Hz, earth-fault current with nominal frequency injected from random phase
angle, results based on statistical distribution of 1000 measurements
2)
Includes the delay of the signal output contact
3)
Maximum Pickup range = 2.5 x In, Pickup range multiples in range of 1.5 to 20
Table 29. Non-directional ground fault protection (51G) main settings
Parameter Function Value (Range) Step
Pickup range 51G 0.05...5.00 x I
n
0.01
Time multiplier 51G 0.05...15.00 0.05
De nite time delay 51G 40...200000 ms 10
Operating curve type
1)
51G De nite or inverse time
Curve type: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13,
14, 15, 17, 18, 19
1)
For further reference please refer to the Operating characteristics table at the end of the Technical data chapter
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