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3-32
Protection Functions
857-UM001A-EN-P – July 2009
Inverse Operation Time (I
Inverse delay means that the operation time depends on the amount
the measured current exceeds the pick-up setting. The bigger the
fault current is, the faster will be the operation. Accomplished
inverse delays are available for the I
types are described under "Inverse Time Operation". The relay will
show a scaleable graph of the configured delay on the local panel
display.
Inverse Time Limitation
The maximum measured secondary residual current is 10xI
maximum measured phase current is 50xI
inverse curves with high pick-up settings. See "Inverse Time
Operation" for more information.
Setting Groups
There are two settings groups available for each stage. Switching
between setting groups can be controlled by digital inputs, virtual
inputs (mimic display, communication, logic) and manually.
Table 3.18 – Parameters of the Undirectional Earth Fault Stage I
Parameter
Value
Status
-
Blocked
Start
Trip
TripTime
SCntr
TCntr
SetGrp
1 or 2
SGrpDI
-
DIx
VIx
LEDx
VOx
Force
Off
On
> stage only)
0
> stage. The inverse delay
0
. This limits the scope of
N
Unit
Description
Current status of the stage
s
Estimated time to trip
Cumulative start counter
Cumulative trip counter
Active setting group
Digital signal to select the active setting
group
None
Digital input
Virtual input
LED indicator signal
Virtual output
Force flag for status forcing for test
purposes. This is a common flag for all
stages and output relays, too.
Automatically reset by a 5-minute
timeout.
and
0N
> (50N/51N)
0
Note
F
F
Clr
Clr
Set
Set
Set
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