Table 39. Negative-sequence overcurrent protection (NSPTOC)
Characteristic Value
Operation accuracy Depending on the frequency of the measured current: f
n
±1.5% of the set value or ±0.002 × I
n
Start time
1)2)
Minimum Typical Maximum
I
Fault
= 2 × set
Start value
I
Fault
= 10 × set
Start value
23 ms
15 ms
26 ms
18 ms
28 ms
20 ms
Reset time Typically 40 ms
Reset ratio Typically 0.96
Retardation time <35 ms
Operate time accuracy in definite time mode ±1.0% of the set value or ±20 ms
Operate time accuracy in inverse time mode
±5.0% of the theoretical value or ±20 ms
3)
Suppression of harmonics DFT: -50 dB at f = n × f
n
, where n = 2, 3, 4, 5,…
1) Negative sequence current before fault = 0.0, f
n
= 50 Hz, results based on statistical distribution of 1000 measurements
2) Includes the delay of the signal output contact
3) Maximum
Start value
= 2.5 × I
n
,
Start value
multiples in range of 1.5...20
Table 40. Negative-sequence overcurrent protection (NSPTOC) main settings
Parameter
Function Value (Range) Step
Start value NSPTOC 0.01...5.00 × I
n
0.01
Time multiplier NSPTOC 0.05...15.00 0.01
Operate delay time NSPTOC 40...200000 ms 10
Operating curve type
1)
NSPTOC Definite 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, see the Operation characteristics table
Table 41. Negative-sequence overcurrent protection for machines (MNSPTOC)
Characteristic
Value
Operation accuracy Depending on the frequency of the measured current: f
n
±1.5% of the set value or ±0.002 x I
n
Start time
1)2)
Minimum Typical Maximum
I
Fault
= 2.0 × set
Start value
23 25 ms 28 ms
Reset time Typically 40 ms
Reset ratio Typically 0.96
Retardation time <35 ms
Operate time accuracy in definite time mode ±1.0% of the set value or ±20 ms
Operate time accuracy in inverse time mode
±5.0% of the theoretical value or ±20 ms
3)
Suppression of harmonics DFT: -50 dB at f = n × f
n
, where n = 2, 3, 4, 5,…
1) Negative-sequence current before = 0.0, f
n
= 50 Hz, results based on statistical distribution of 1000 measurements
2) Includes the delay of the signal output contact
3)
Start value
multiples in range of 1.10...5.00
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