ABB RET630 - Residual Overvoltage Protection; Frequency Gradient Protection

Table 55. 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 56. 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 57. 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 1MRS756788 A
RET630
Product version: 1.0 Issued: 15.09.2009
ABB 41