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

L Protection

t
L
I1
t1
62 | © 2017 ABB | 1SDH001330R0002 - ECN000058721 Rev. A
Path
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Function
L protection protects against overloads
NOTE: the protection is available and active for all the versions of the trip unit. You can disable
the protection by configuring the trip unit 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
Here is a list of the available parameters:
Parameter Description
It determines the dynamic of the curve and the calculation of the tripping time,
conforming to various reference standards:
• t = k / I
• IEC 60255-151 SI
• IEC 60255-151 VI
• IEC 60255-151 EI
Curve
• t = k / I
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 73.
than 1 second, it is automatically limited to 1 second.
The value I1 contributes in calculating the tripping time, and also defines the current
value that, if exceeded, activates the protection (with reference to the curve, it is the
part parallel to the y-axis).
It is represented both as an absolute value (Ampere) and as a relative value (In, nominal
Threshold I1 value defined by the Rating Plug).
between 1.05 and 1.2 of the I1 threshold set. Example (with I1 set = 400 A):
the protection is activated for currents read between 420 A and 480 A.
The value T1 contributes to calculate the tripping time (with reference to the curve, T1
affects the entire curve shifting it along the vertical axis).
Time t1
The protection limits the tripping time to 1 second in two cases:
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 can be set by
I1 Prealarm the user, and is deactivated in two cases:
• Current lower than the prealarm threshold.
• Current higher than the protection activation threshold.
A value within the 50 % ... 90 % range can be entered, with 1 % steps.
L protection has Thermal Memory, see page 71.
according to IEC 60947-2.
2
according to IEC 60255-151
4
IMPORTANT: if from the calculation the tripping time turns out to be less
IMPORTANT: the protection is activated and starts timing for currents
IMPORTANT:
• if, according to the calculation, the time is less than 1 second.
• If the fault current is greater than 12 In.
ABB | SACE Emax 2
Ekip Touch protection trip unit | 9 - Touch protections