ABB RELION REX640 Technical Manual page 1123

1MRS759142 C
REX640
Technical Manual
• Immediately after the fault occurrence, the estimate is affected by initial fault
transients in voltages and currents.
• Approximately one fundamental cycle after the fault occurrence, the fault
distance estimate starts to approach the final value.
• Approximately two fundamental cycles after the fault occurrence, the stability
criterion for fault distance estimate is fulfilled and the TRIGG_OUT event is sent.
The recorded data values are stored at this moment.
GUID-6E0FE428-C55C-40E4-B489-D375C3D91DF9 V1 EN
Figure 607: The behavior of fault distance estimate in time
Alarm indication
SCEFRFLO contains an alarm output for the calculated fault distance. If the
calculated fault distance FLT_DISTANCE is between the settings Low alarm Dis
limit and High alarm Dis limit, the ALARM output is activated. If setting High alarm
Dis limit has been set below Low alarm Dis limit, the ALARM operation is inverted:
the ALARM output is activated if High alarm Dis limit is undershot or Low alarm Dis
limit is exceeded. The default value for both is zero so that no distance estimate
activates ALARM.
The ALARM output can be used, for example, in regions with waterways or other
places where knowledge of certain fault locations is of high importance.
Protection related functions
Section 5
1117