Table 58. Negative-sequence overvoltage protection (NSPTOV)
Characteristic
Value
Operation accuracy
At the frequency f = f
n
±1.5% of the set value or ±0.002 × U
n
Start time
1)2)
U
Fault
= 1.1 x set
Start value
U
Fault
= 2.0 x set
Start value
Typical 29 ms (± 15ms)
Typical 24 ms (± 15ms)
Reset time
< 40 ms
Reset ratio
Typical 0.96
Retardation time
< 35 ms
Operate time accuracy in definite time mode
±1.0% of the set value or ±20 ms
Suppression of harmonics
DFT: -50 dB at f = n × f
n
, where n = 2, 3, 4, 5,
…
1) Residual voltage before fault = 0.0 × U
n
, f
n
= 50 Hz, residual overvoltage with nominal frequency injected from
random phase angle
2) Includes the delay of the signal output contact
Table 59. Negative-sequence overvoltage protection (NSPTOV) main settings
Parameter
Function
Value (Range)
Step
Start value
NSPTOV
0.010...1.000 pu
0.001
Operate delay time
NSPTOV
0.040...120.000 s
0.001
Transformer Protection and Control
1MRS756978 D
RET630
Product version: 1.1
Issued: 2011-05-18
ABB
47