2.13 Earth fault protection I0>
(50N/51N)
2 Protection functions Technical description
68
VAMP 24h support phone +358 (0)20 753 3264 VM50.EN004
Parameter Value Unit Description Note
Input Io1
IoCalc
Io1Peak
X1-7,8,9. See chapter 8.
IL1 + IL2 + IL3
X1-7,8,9 peak mode (I
0
>
only)
Set
Intrmt s Intermittent time Set
Dly20x s Delay at 20xIon
Dly4x s Delay at 4xIon
Dly2x s Delay at 2xIon
Dly1x s Delay at 1xIon
A, B, C, D,
E
User's constants for standard
equations. Type=Parameters.
See chapter 2.23.
Set
For details of setting ranges see chapter 9.3.
Set = An editable parameter (password needed)
C = Can be cleared to zero
F = Editable when force flag is on
Recorded values of the latest eight faults
There is detailed information available of the eight latest earth
faults: Time stamp, fault current, elapsed delay and setting
group.
Recorded values of the directional earth fault stages (8 latest
faults) I
0
>, I
0
>> (67N)
Parameter Value Unit Description
yyyy-mm-dd Time stamp of the recording, date
hh:mm:ss.ms Time stamp, time of day
Flt pu Maximum earth fault current
EDly %
Elapsed time of the operating time
setting. 100% = trip
Angle
Fault angle of I
0
. –U
0
= 0
Uo % Max. U
0
voltage during the fault
SetGrp 1
2
Active setting group during fault
2.13. Earth fault protection I
0
> (50N/51N)
The undirectional earth fault protection is to detect earth faults
in low impedance earthed networks. In high impedance earthed
networks, compensated networks and isolated networks
undirectional earth fault can be used as back-up protection.
The undirectional earth fault function is sensitive to the
fundamental frequency component of the residual current 3I
0
.
The attenuation of the third harmonic is more than 60 dB.
Whenever this fundamental value exceeds the user's pick-up
setting of a particular stage, this stage picks up and a start
signal is issued. If the fault situation remains on longer than
the user's operation time delay setting, a trip signal is issued.
To Next Page
Loading...
