ABB SACE Tmax XT2 User Manual page 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:


To verify and simulate the trip times based on all the parameters, see:


Parameters
Parameter
Enable
Trip Enable
Version
Threshold I6
Time t6
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.
1SDH002031A1002 ECN000092998
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
Protection summary table with the operating characteristics (page 78)
Chart with tripping curve (page 87)
Description
Enables/disables protection and availability on menu of the
parameters
Activates/deactivates the open command: if disabled, the alarm
and the lapsing of the protection time are managed only as
information
Enables the unbalance calculation method to be selected:

Old: % Sbil = 100 x (I

New: % Sbil = 100 x = 100 x (max I
NOTE:
currents, calculated by comparing each current with the
average value; I
Defines the trip value that activates the protection.
The unbalance is expressed as a percentage value in a range:
2 % .. 90 %, with 1 % step
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
Rev. B
- I ) / I
max min max

max I : maximum deviation between measured
mi
: average value of the read currents
mi
) / I
mi mi
SACE Tmax XT2 – XT4 | 43
Default
OFF
OFF
Old
50 %
5 s