◦ With option »Reset Mode« = “inverse time” (only available for IEC and◦
ANSI/IEEE curves): The reset delay is calculated based on the selected
characteristics.
• tChar (for all characteristics except “DEFT”):•
◦ Time multiplier/tripping characteristic factor. The setting range depends on the◦
selected tripping curve.
◦ Setting via [Protection Para / IG>] »tChar«◦
For all inverse-time characteristics (i. e. all curves except the DEFT), there are two minimum
trip delays, and independent of the selected characteristic will the actual trip delay never be
smaller than any of these two minimum delays.
• »IG> . tMin« is a minimum delay settable by the user. So, this is simply a timer•
that is triggered independent of the inverse-time curve and that has to elapse before
the protection stage trips. If it is set to 0 seconds it is deactivated. (See also ╚═▷
“4.5.2.1 Earth (Ground) Overcurrent Protection – Settings via DiggiMEC or via Smart
view”.)
•
Another minimum delay, t
Dyn.Lim.
, results from a calculated “knee-point” of the
•
characteristic. This means it is dependent on a particular current value on the curve,
I
G,Dyn.Lim.
. The eective trip delay does never fall below t
Dyn.Lim.
, independent of the
actual value of IG.
◦ I
G,Dyn.Lim.
is dened as the smallest value out of these three values:◦
20⋅I
G>
(EF Curve: 30⋅I
G>
),
20⋅In
,max
, if calculated ground/earth current IG calc is used,
20⋅IGnom, if measured ground/earth current IG meas is used.
◦ Then t
Dyn.Lim.
is the delay time that is calculated from this I
G,Dyn.Lim.
based on◦
the selected characteristic.
◦ (The diagram of each characteristic curve shows this “knee-point”, assuming◦
the example value I
G,Dyn.Lim.
= 20⋅I
G>
[EF Curve: 30⋅I
G>
].)
◦ Exception: For »Char« = “RXIDG”, t
Dyn.Lim.
is independent of I
G,Dyn.Lim.
, but has◦
the xed value t
Dyn.Lim.
= 0.02 s
290 WIC1 WIC1-1.0-EN-MAN
11 Appendix
11.2.2 Characteristics (IG>, IG>>)
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