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3-78
Protection Functions
857-UM001A-EN-P – July 2009
Fully programmable inverse delay characteristics
Building the characteristics by setting 16 [current, time] points.
The relay interpolates the values between given points with 2nd
degree polynomials. This mode is activated by setting curve
family to 'PrgN''. There are maximum three different
programmable curves available at the same time. Each
programmed curve can be used by any number of protection
stages. See "Programmable Inverse Time Curves".
Local Panel Graph
The relay will show a graph of the currently used inverse delay on
the local panel display. Up and down keys can be used for zooming.
Also the delays at 20xI
SET
Inverse Time Setting Error Signal
If there are any errors in the inverse delay configuration the
appropriate protection stage will use definite time delay.
There is a signal 'Setting Error' available in output matrix, which
indicates three different situations:
1. Settings are currently changed with SetPointPS or local panel,
and there is temporarily an illegal combination of
curve/delay/points. For example if previous settings were
IEC/NI and then curve family is changed to IEEE, the setting
error will active, because there is no NI type available for IEEE
curves. After changing valid delay type for IEEE mode (for
example MI), the 'Setting Error' signal will release.
There are errors in formula parameters A...E, and the device
is not able to build the delay curve
There are errors in the programmable curve configuration
and the device is not able to interpolate values between the
given points.
Limitation
The maximum measured phase current is 50xI
directly measured earth fault current is 5xI
inverse delay curves goes up to 20 times the setting. At high setting,
the maximum measurement capability limits the scope of inverse
curves according to the following table.
, 4xI
and 2xI
are shown.
SET
SET
and the maximum
N
. The full scope of
0N
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