Figure 208: Example of INTRPTEF operation in ”Transient EF” mode in the faulty
feeder
In the "Intermittent EF" mode the OPERATE output is activated when the following
conditions are fulfilled:
• the number of transients that have been detected exceeds the
Peak counter limit
setting
• the timer has reached the time set with the
Operate delay time
• and one additional transient is detected during the drop-off cycle
The
Reset delay time
starts to elapse from each detected transient (peak). In case
there is no OPERATE activation, for example, the fault disappears momentarily
START stays activated until the
Reset delay time
elapses, that is, reset takes place
if time between transients is more than
Reset delay time
. After OPERATE activation,
a fixed pulse length of 100 ms for OPERATE is given, whereas START is reset after
Reset delay time
elapses
1MRS757644 H
Protection functions
620 series
Technical Manual
423
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