4.3.3.9
Technical data
Table 500: LREFPNDF Technical data
Characteristic
Value
Operation accuracy
Depending on the frequency of the measured current: f
n
±2
Hz
±2.5% of the set value or ±0.002 x I
n
Start time ,
Minimum
Typical
Maximum
I
Fault
= 2.0 × set
Operate value 37 ms
41 ms
45 ms
Reset time
Typically 40 ms
Reset ratio
Typically 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, …
4.3.3.10
Technical revision history
Table 501: LREFPNDF Technical revision history
Technical revision
Change
B
Unit for setting
Start value 2.H
changed from
%In to %.
C
Internal Improvement.
4.3.4
High-impedance based restricted earth-fault protection
HREFPDIF
4.3.4.1
Identification
Function description
IEC 61850
identification
IEC 60617
identification
ANSI/IEEE C37.2
device number
High-impedance based restricted
earth-fault protection
HREFPDIF
dIoHi>
87NH
4.3.4.2
Function block
Figure 295: Function block
1
Current before fault = 0.0, f
n
= 50 Hz, results based on statistical distribution of 1000 measure-
ments
2
Includes the delay of the signal output contact
1MRS757644 H
Protection functions
620 series
Technical Manual
569
