ABB SACE Tmax XT2 User Manual page 37

S Protection Function
If the current of one or more phases exceeds the I2 threshold, the protection is activated and,
after a time determined by the value read and the parameters set, it sends the TRIP command.
To verify and simulate the trip times based on all the parameters, see:


Parameters
Parameter
Enable
Trip Enable
Function
Threshold I2
Time t2
Thermal
memory
Zone
Selectivity
Selectivity
time
StartUp
enable
StartUp
threshold
StartUp time
Constraints, limitations, and additional functions


1SDH002031A1002 ECN000092998
Protection summary table with the formulas for calculations (page 78)
Chart with tripping curve (page 84)
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
Determines the curve dynamic and threshold or the calculation of
trip time:

t= k: trip at set time

2
t= k/I : dynamic inverse time-delay trip
Defines the value that activates protection and contributes to
calculating trip time.
The value is expressed both as an absolute value (Ampere) and as
a relative value (In), settable in a range: 0.6 In .. 10In with 0.1 In
step
Depending on the type of curve selected, this is the trip time or
contributes to calculating timing.
The value is expressed in seconds, which are settable in a range:
0.05 s .. 0.4 s, with 0.01 s step
Activates/deactivates the thermal memory function, see page 70 for
details
NOTE: the function is available only with a curve t=k/I
Activates/deactivates the function and the display availability of
selectivity time, see page 70 for details
NOTE: the function is available only with curve t = k
This is the trip time of the protection with the zone selectivity
function active and the selectivity input not present see page 70for
details
The value is expressed in seconds, which are settable in a range:
0.04 s .. 0.2 s, with 0.01 s step
Activates/deactivates the function and display availability of the
combined parameters, see page 73 for details
Protection threshold valid during Startup time, in conditions in which
the function is active, see page 73 for details
The value is expressed both as an absolute value (Ampere) and as
a relative value (In), settable in a range: 0.6 In .. 10In with 0.1 In
step
This is the time for which the StartUp threshold is active, calculated
from tripping of activation threshold, set details on page 73
The value is expressed in seconds, which are settable in a range:
0.1 s .. 30 s, with 0.01 s step
The I2 threshold must be greater than the I1 threshold (if the S protection is active)
2
With curve t = k/I the trip time is forced to t2 if the calculations result in a theoretical value
that is lower than t2 itself
Rev. B
Default
OFF
ON
t= k
2 In
0.05 s
OFF
2
OFF
0.04 s
OFF
0.6 In
0.1 s
SACE Tmax XT2 – XT4 | 37