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8.2.2 Evaluation of Transient and Arcing Faults
An arcing earth fault is characterized by its transient nature. It extinguishes and then returns with a new
transient after a certain time or with a certain frequency. If the time delay is short enough, a single
transient may be sufficient for the detector to go to the
TRIP
state. If an error occurs and the detector
reaches the
START
state, the
reignition
timer is started. If the fault returns within the set reignition time,
the detector will indicate
TRIP
immediately when the
START
state is reached. Thus, it does not wait for the
normal time delay between
START
and
TRIP
to expire. Two consecutive starts within a certain time is
evaluated as an arcing fault. The method ensures that an arcing error does not start and reset repeatedly.
Figure 9.
Earth fault with arcing characteristics
–
after the second ”
START
”
the detector progresses immediately to
state TRIP.
-1,5
-1
-0,5
0
0,5
1
1,5
2
2,5
Earth Fault - Arcing
L1
L2
L3
In
0
2
4
6
8
10
1
23
45
67
89
111
133
155
177
199
221
243
265
287
309
331
353
375
397
419
441
463
485
507
529
551
573
595
617
639
661
683
705
727
749
771
793
815
837
859
881
State
Reignition time