Table 60. Residual overvoltage protection (ROVPTOV)
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
Typical 27 ms (± 15 ms)
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 voltage with nominal frequency injected from
random phase angle
2) Includes the delay of the signal output contact
Table 61. Residual overvoltage protection (ROVPTOV) main settings
Parameter
Function
Value (Range)
Step
Start value
ROVPTOV
0.010...1.000 pu
0.001
Operate delay time
ROVPTOV
0.040...300.000 s
0.001
Table 62. Frequency gradient protection (DAPFRC)
Characteristic
Value
Operation accuracy
df/dt < ± 10 Hz/s: ±10 mHz/s
Undervoltage blocking: ±1.5% of the set
value or ±0.002 × U
n
Start time
1)2)
Start value
= 0.05 Hz/
s
df/dt
FAULT
= ±1.0 Hz/s
Typical 110 ms (±15 ms)
Reset time
< 150 ms
Operate time accuracy in definite time mode
±1.0% of the set value or ±30 ms
Suppression of harmonics
DFT: -50 dB at f = n × f
n
, where n = 2, 3, 4, 5,
…
1) Frequency before fault = 1.0 × f
n
, f
n
= 50 Hz
2) Includes the delay of the signal output contact
Transformer Protection and Control
1MRS756978 D
RET630
Product version: 1.1
Issued: 2011-05-18
48
ABB
