Table 33. Directional earth-fault protection (DEFxPDEF)
Characteristic Value
Operation accuracy At the frequency f = f
n
DEFLPDEF
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°
DEFHPDEF 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)
DEFHPDEF and
DEFLPTDEF:
I
Fault
= 2 x set Start
value
Typical 54 ms (±15 ms)
Reset time < 40 ms
Reset ratio Typical 0.96
Retardation time < 30 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: -50dB at f = n x f
n
, where n = 2, 3, 4, 5,
…
Peak-to-Peak: No suppression
1)
Set Operate delay time = 0.06 s,Operate curve type = IEC definite time, Measurement mode = default (depends on
stage), current before fault = 0.0 x I
n
, f
n
= 50 Hz, earth-fault current 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 1MRS756788 A
RET630
Product version: 1.0 Issued: 15.09.2009
30 ABB
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