IG-150-EN version 04; 03/10/16
55
General instructions
ekor.rps
Protection functions. Description and settings
Working with curve, the time to trip depends on the
selected curve (family and index) and the current value.
The curves which are normal, very inverse and extremely
inverse, or user curves can be selected as corresponding
to the standard BS142 (IEC 255-4) or ANSI. In appendix II
graphics and formulas for calculating the time are given, as
a function of the ratio between the current and the pickup
current. If the ratio is higher than 40, 40 will be taken for
calculating.
It is also possible to program 4 user curves.
The unit allows setting the drop time characteristics,
emulating the induction disc of the electromechanical
relays and allowing a better coordination of the protection.
If the enabling is set at "YES+REDROP" and the current
decreases below the 95 % of the set value, the trip drops
instantaneously and the pickup drop time will depend on
the selected curve (family and index) and o the current.
If the selected curve is denite time, the pickup will drop
when the programmed time since it decreases below the
pick up current elapses, regardless the current value. (See
“curves for timed characteristic” in appendix II).
If the enabling is set at "YES" and the current decreases
below the 95 % of the set value, the trip and the pick up
drop instantaneously.
The maximum error in times, for values higher than 50 ms,
is 30 ms or 5 % of the theoretical value (the higher of the
two). For the denite time setting of 0 ms, the behavior is
the same as for the instantaneous characteristic (see next
paragraph).
If an unacceptable index value is programmed
for a type of curve, the unit takes the closest
acceptable value.
4.1.3. Timing cancellation
Through the console screen “timing cancellation” or
through keyboard/display (in the CURRENT PROT., in
TIMING CANCELATION) a digital or logical input can be
programmed for every overcurrent timed , so that if the
function is activated it is not timed any more and behaves
as instantaneous.
4.1.4. Settings ranges of the instantaneous characteristic (low level) (6 tables) (normal and HIGH2)
Setting Min Max Step Notes
Enable
YES/NO/pick up
Phase instantaneous trip [A]
0.02 40.00 0.01 With standard ratings
0.1 200.0 0.01 With specied ratings
Additional time [s]
0.00 60.00 0.01
Special function
See “Instantaneous special operation”
These settings can be found in the console on the screen “overcurrent protection (1)”. INSTANT PHASES box
Table 4.2. Settings ranges of the instantaneous characteristic
The trip current is set in secondary amperes.
If additional time 0 is programmed, for current values
between the tripping current and 1.5 times that value,
it trips between 40 and 50 ms; for 2 times the tripping
current between 35 and 40 ms, and from 3 times the
tripping currents, on 30 to 35 ms. If an additional time is
programmed, this is added to the indicated time.
With additional times higher than 50 ms the maximum time
error is 30 ms or 5 % of the theoretical value (the higher of
the two).
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