1SDH002031A1002 ECN000092998 Rev. B SACE Tmax XT2 – XT4 | 49
Function
The protection is activated in the event of an imbalance between the line-to-line voltages read by
the Trip unit. If the detected imbalance exceeds the U14 threshold for a time greater than t14,
the protection sends the TRIP command.
The protection automatically cuts out if the maximum line-to-line voltage value is less than 0.3
Un.
To verify and simulate the trip times based on all the parameters, see:
Protection summary table with the operating characteristics (page 79)
Chart with tripping curve (page 88)
Parameters
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
Defines the unbalance value that activates the protection.
The unbalance is expressed as a percentage value and is
calculated as follows: % Sbil = 100 x (max U
mi
) / U
mi
in a range: 2 % .. 90 %, with 1 % step.
NOTE:
max U
mi
: maximum deviation between the three
voltages by comparing each network voltage with the
average value;
U
mi
: average value of the network voltages
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
Constraints, limitations, and additional functions
From the service connector (with Ekip Connect) or with system bus communication it is also
possible to access the block functions, see page70.
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