S Protection - ABB SACE Emax E1.2 Operating Instructions For The Design Engineer

S Protection

t
I2 S
t2
63 | © 2017 ABB | 1SDH001330R0002 - ECN000058721 Rev. A
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Function
S protection protects against selective short circuit.
NOTE: the protection is available for LSI and LSIG versions of the trip unit.
When the activation threshold is exceeded, the protection trips within a fixed or dynamic time (the time
decreases as the current reading increases).
I
Parameters
Here is a list of the available parameters:
Parameter Description
Enable To activate/deactivate the protection.
It determines the dynamic of the curve and the tripping time, fixed or dynamic
according to the selection:
• t = k (ANSI 50TD): fixed time trip.
Curve
• t = k / I
The calculation of the tripping time of the inverse time curve is based on a
mathematical expression. The details are provided in the table on page 73.
It defines the current value that activates the protection when exceeded (with
reference to the figure above, the threshold is the part of the curve parallel to the
y-axis).
It is represented both as an absolute value (Ampere) and as a relative value (In,
nominal value defined by the Rating Plug).
Threshold I2
The selected function determines the contribution of t2:
• t = k: t2 is the delay time between the exceeding of the I2 threshold and the
sending of the opening command.
• t = k / I
Time t2 above curve, t2 affects the curve, shifting it along the vertical axis).
S protection has Trip Enable, Thermal Memory, Zone Selectivity, Startup Enable, see page 71.
Via Ekip Connect it is also possible to access the blocking functions, see page 72.
(ANSI 51): inverse time dynamic tripping.
2
IMPORTANT: The I2 threshold set must be higher than the I1
threshold. An incorrect configuration gives an error on the display and
the programming session doesn't conclude, with consequent rejection
of the changes made to the parameters.
: t2 contributes in calculating the tripping time (with reference to the
2
IMPORTANT: the minimum tripping time for the protection is t2. If
according to the calculation the tripping time is less, it is automatically
limited to t2.
ABB | SACE Emax 2
Ekip Touch protection trip unit | 9 - Touch protections