L Protection - ABB SACE Emax 2 Series Installation, Operation And Maintenance Instructions

L Protection

t
I1 L
t1
85 | © 2013 ABB | 1SDH001000R0002 - L7804
Path
Main page - Menus - Protections
Function
The protection L protects against overloads
NOTE: the protection is available and active for all the versions of the release. You
can disable the protection by configuring the release with rating plug L = Off.
When the activation threshold is exceeded, the protection trips in a time that decreases as the
current read increases.
I
Parameters
The following is a description of the parameters:
Parameter Description
It determines the dynamic of the curve and the calculation of the
tripping time, conforming to various reference standards:
Function
Each function corresponds to a mathematical expression that allows
the tripping time to be calculated. The details of the expressions are
provided in the table on page 94.
The value I1 contributes in calculating the tripping time, and also
defines the current value that, if exceeded, activates the protection (in
reference to the curve, it is the part parallel to the ordinate).
It is represented both as an absolute value (Ampere) and as a relative
value (In, nominal value defined by the Rating Plug).
Threshold (I1)
The value T1 contributes in calculating the tripping time (in reference to
the curve, T1 affects the entire curve shifting it along the vertical axis).
Time (t1)
The prealarm of L allows notification that the measured current is near
the activation threshold of the protection.
The prealarm state is activated for currents higher than a threshold that
Prealarm I1
can be set by the user, and is deactivated in two cases:
• t=k/i according to IEC 60947-2.
2
• IEC 60255-3 SI.
• IEC 60255-3 VI.
• IEC 60255-3 EI.
• t=k/i according to 60255-3.
4
IMPORTANT: if from the calculation the tripping time turns
out to be less than 1 second, it is automatically limited to 1
second.
IMPORTANT: the protection is activated and starts timing
for currents between 1.05 and 1.2 of the I1 threshold set.
Example (with I1 set = 400 A): the protection is activate for
currents read between 420 A and 480 A.
IMPORTANT: the parameter is used if the selected function
is t=k/i
.
2
• Current lower than the prealarm threshold.
• Current higher than the protection activation threshold.
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