ABB RET615 Product Manual page 38

Transformer Protection and Control
RET615
Product version: 4.0
Table 34. Negative phase-sequence overcurrent protection (NSPTOC)
Characteristic
Operation accuracy
1)2)
Start time
Reset time
Reset ratio
Retardation time
Operate time accuracy in definite time mode
Operate time accuracy in inverse time mode
Suppression of harmonics
1) Negative sequence current before fault = 0.0, f
2) Includes the delay of the signal output contact
Start value = 2.5 x I Start value multiples in range of 1.5 to 20
3) Maximum ,
n
Table 35. Negative phase-sequence overcurrent protection (NSPTOC) main settings
Parameter
Start value
Time multiplier
Operate delay time
1)
Operating curve type
1) For further reference please refer to the Operating characteristics table
38
Start value
I = 2 x set
Fault
Start value
I = 10 x set
Fault
= 50 Hz, results based on statistical distribution of 1000 measurements
n
Function
NSPTOC
NSPTOC
NSPTOC
NSPTOC
Value
Depending on the frequency of the current measured: f
±2 Hz
±1.5% of the set value or ±0.002 x I
Minimum Typical
22 ms 24 ms
14 ms 16 ms
< 40 ms
Typical 0.96
< 35 ms
±1.0% of the set value or ±20 ms
±5.0% of the theoretical value or ±20 ms
DFT: -50 dB at f = n x f , where n = 2, 3, 4, 5,...
n
Value (Range)
0.01...5.00 x I
n
0.05...15.00
40...200000 ms
Definite or inverse time
Curve type: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15,
17, 18, 19
1MRS756891 F
n
n
Maximum
25 ms
17 ms
3)
Step
0.01
0.01
10
ABB