Table 32. Three-phase directional overcurrent protection (DPHxPDOC)
Characteristic
Value
Operation accuracy
At the frequency f = f
n
DPHLPDOC
Current:
±1.5% of the set value or ±0.002 x I
n
Voltage:
±1.5% of the set value or ±0.002 x U
n
Phase angle:
±2°
DPHHPDOC
Current:
±1.5% of the set value or ±0.002 x I
n
(at
currents in the range of 0.1…10 x I
n
)
±5.0% of the set value (at currents in the
range of 10…40 x I
n
)
Voltage:
±1.5% of the set value or ±0.002 x U
n
Phase angle:
±2°
Start time
1)2)
I
Fault
= 2.0 x set
Start
value
Typical: 24 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
Operate time accuracy in inverse time mode
±5.0% of the theoretical value or ±20 ms
3)
Suppression of harmonics
RMS: No suppression
DFT: -50 dB at f = n x f
n
, where n = 2, 3, 4, 5,
…
Peak-to-Peak: No suppression
P-to-P+backup: No suppression
1)
Measurement mode
= default (depends of stage), current before fault = 0.0 x I
n
, f
n
= 50 Hz, fault current in one
phase with nominal frequency injected from random phase angle, results based on statistical distribution of 1000
measurements
2) Includes the delay of the signal output contact
3) Maximum
Start value
= 2.5 x I
n
,
Start value
multiples in range of 1.5 to 20
Transformer Protection and Control
1MRS756978 D
RET630
Product version: 1.1
Issued: 2011-05-18
ABB
31
