ABB RET615 Product Manual page 36

Transformer Protection and Control
RET615
Product version: 4.0
Table 30. Non-directional earth-fault protection (EFxPTOC)
Characteristic
Operation accuracy
1)2)
Start time
Reset time
Reset ratio
Retardation time
Operate time accuracy in definite time mode
Operate time accuracy in inverse time mode
Suppression of harmonics
1) Measurement mode = default (depends on stage), current before fault = 0.0 x I
random phase angle, results based on statistical distribution of 1000 measurements
2) Includes the delay of the signal output contact
Start value = 2.5 x I Start value multiples in range of 1.5 to 20
3) Maximum ,
n
36
EFLPTOC
EFHPTOC
and
EFIPTOC
EFIPTOC:
Start value
I = 2 x set
Fault
Start value
I = 10 x set
Fault
EFHPTOC and EFLPTOC:
Start value
I = 2 x set
Fault
Value
Depending on the frequency of the current measured: f
±2 Hz
±1.5% of the set value or ±0.002 x I
±1.5% of set value or ±0.002 x I
(at currents in the range of 0.1...10 x I
±5.0% of the set value
(at currents in the range of 10...40 x I
Minimum Typical
16 ms 19 ms
11 ms 12 ms
22 ms 24 ms
< 40 ms
Typical 0.96
< 30 ms
±1.0% of the set value or ±20 ms
±5.0% of the theoretical value or ±20 ms
RMS: No suppression
DFT: -50 dB at f = n x f , where n = 2, 3, 4, 5,...
n
Peak-to-Peak: No suppression
, f = 50 Hz, earth-fault current with nominal frequency injected from
n n
1MRS756891 F
n
n
n
)
n
)
n
Maximum
23 ms
14 ms
25 ms
3)
ABB