ABB SACE Tmax XT5 Operation And Maintenance Manual page 42

L Protection
t
I1
t1
40 | © 2019 ABB | 1SDH002039A1002 - ECN000093027 - Rev. A
Function
If the current of one or more phases exceeds threshold I1, the protection trips and, after a time established
by the value read and by the parameter settings, transmits the TRIP command.
L
To check and simulate the trip times in relation to all the parameters, please consult:
• the summary table of the protections with the calculation formulas (page 79)
• the graph with trip curve (from page 82)
Parameters
I
NOTE: the limitations and default parameters of the Ekip M Touch Trip unit are different from
those of the other models. Details are given after the table
Parameter Description
Establishes curve dynamics and trip time calculation:
• t = k / I
• IEC 60255-151 SI
Curve
• IEC 60255-151 VI
• IEC 60255-151 EI
• t = k / I
Establishes the value that activates the protection and contributes
towards calculating the trip time.
Threshold I1
The value is given as both absolute value (A) and relative value (In) and
can be set within the range: 0.4 In to 1 In, in 0.001 In steps
Contributes towards calculating the trip time.
The value is given in seconds and can be set within the range: 3 s ..
Time t1
48 s (for curve t = k / I
Activates/deactivates the thermal memory function (page 72)
Thermal
memory
Warns that the measured current is near to protection activation
threshold I1.
The value is given in percentage of threshold I1 and can be set within
the range: 50% I1 to 90% I1, in 1% steps.
Prealarm I1
Ekip M Touch
With Ekip M Touch, L protection features the following differences compared to the other models:
• Curve: non-editable; specific for Ekip M Touch (page 85)
• Time t1: non-editable; determined by the Trip class (page 68)
• Thermal memory: always enabled, functions according to standard IEC 60255-8; thermal memory reset
time is established by the Trip class (page 68)
• Different default parameters: I1 = 0.4 In; t1 = 45 s (Class = 20E)
Limitations and additional functions
• threshold I1 must be lower than threshold I2 (if S protection is activated)
• the trip time of the protection is forcibly set at 1 s if the calculation results give a lower theoretical value
and/or if the current reading is more than 12 In
according to IEC 60947-2.
2
according to 60255-151
4
) or 3 s .. 9 s (for the other curves), in 1 s steps
2
NOTE: the function is always ON with Ekip M Touch and
available with curve t = k / I
2
NOTE: the prealarm condition deactivates in two cases:
• current lower than prealarm threshold I1
• current higher than threshold I1
for all the other trip unit models
Protections | 1 - Standard Protections
ABB | SACE Tmax XT
Default
t = k/I
2
1 In
48 s
OFF
90 % I1