ABB SACE Tmax XT2 - Page 43

1SDH002031A1002 ECN000092998 Rev. B SACE Tmax XT2 – XT4 | 43
IU Protection
Function
The protection is activated in the event of an imbalance between the currents detected. If the
detected imbalance exceeds the I6 threshold for a time greater than t6, the protection sends the
TRIP command.
The protection automatically cuts out in two cases:
 The measurement of at least one current is greater than 6 In
 The maximum current value of all phases is less than 0.3 In
To verify and simulate the trip times based on all the parameters, see:
 Protection summary table with the operating characteristics (page 78)
 Chart with tripping curve (page 87)
Parameters
Parameter
Description
Default
Enable
Enables/disables protection and availability on menu of the
parameters
OFF
Trip Enable
Activates/deactivates the open command: if disabled, the alarm
and the lapsing of the protection time are managed only as
information
OFF
Version
Enables the unbalance calculation method to be selected:
 Old: % Sbil = 100 x (I
max
- I
min
) / I
max
 New: % Sbil = 100 x = 100 x (max I
mi
) / I
mi
NOTE:  max I
mi
: maximum deviation between measured
currents, calculated by comparing each current with the
average value; I
mi
: average value of the read currents
Old
Threshold I6
Defines the trip value that activates the protection.
The unbalance is expressed as a percentage value in a range:
2 % .. 90 %, with 1 % step
50 %
Time t6
This is the trip time of the protection; the value is expressed in
seconds, which are settable in a range: 0.5 s .. 60 s with 0.5 s step
5 s
Ekip M Touch
With Ekip M Touch IU protection is inhibited if the rms value of at least one of the phase currents
is less than 0.25 In.