Alarm Indication - ABB 615 series Technical Manual

1MAC059074-MB A
5.7.4.4
615 series ANSI
Technical Manual
Generally, 21FL requires a minimum of two fundamental cycles of measuring time after
the fault occurrence. Figure 421
21FL as a function of time.
• 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-2C1E2C55-B61A-4200-BC8E-0F6FC9036A56 V3 EN
Figure 421: The behavior of fault distance estimate in time

Alarm indication

21Fl 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.
The ALARM output can be utilized, for example, in regions with waterways or other places
where knowledge of certain fault locations is of high importance.
Protection related functions
illustrates typical behavior of fault distance estimate of
Section 5
823