Table 37. Rotor earth-fault protection (MREFPTOC) main settings
Parameter Function Values (Range) Step
Alarm start value MREFPTOC 0.010 - 2.000 0.001
Operate start value MREFPTOC 0.010 - 2.000 0.001
Alarm delay time MREFPTOC 0.04 - 200.00 0.01
Operate delay time MREFPTOC 0.04 - 200.00 0.01
Table 38. Negative-sequence overcurrent protection for motors (MNSPTOC)
Characteristic
Value
Operation accuracy At the frequency f = f
n
±1.5% of the set value or ±0.002 × I
n
Start time
1)2)
I
Fault
= 5.0 x set Start
value
Typical 43 ms (±15 ms)
Reset time < 70 ms
Reset ratio Typical 0.96
Retardation time < 35 ms
Operate time accuracy in definite time mode ±1.0% of the set value or ±35 ms
Operate time accuracy in inverse time mode
±5.0% of the theoretical value or ±30 ms
3)
Suppression of harmonics DFT: -50 dB at f = n x f
n
, where n = 2, 3, 4, 5,
…
1) Negative-sequence current before = 0.0 × I
n
, f
n
= 50 Hz
2) Includes the delay of the signal output contact
3)
Start value multiples in range of 1.10 to 5.00
Table 39. Negative-sequence overcurrent protection for motors (MNSPTOC) main settings
Parameter
Function Value (Range) Step
Start value MNSPTOC 0.01...0.50 pu 0.01
Operating curve type MNSPTOC ANSI Def. Time
IEC Def. Time
Inv. Curve A
Inv. Curve B
-
Operate delay time MNSPTOC 0.10...120.00 s 0.01
Cooling time MNSPTOC 5...7200 s 1
Motor Protection and Control 1MRS756977 D
REM630
Product version: 1.1 Issued: 2011-05-18
34 ABB
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