ABB XT7, Руководство по эксплуатации и обслуживанию

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ABB | SACE Tmax XT
44 | © 2020 ABB | 1SDH001821A1002 - ECN000135670 Protections | 7 - Standard Protections
L Protection
L I1
t
t1
I
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.
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 87)
• the graph with trip curve (from page 91)
Parameters
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 Default
Curve
Establishes curve dynamics and trip time calculation:
• t = k / I
2
according to IEC 60947-2.
• IEC 60255-151 SI
• IEC 60255-151 VI
• IEC 60255-151 EI
• t = k / I
4
according to 60255-151
t = k/I 2
Threshold I1
Establishes the value that activates the protection and contributes
towards calculating the trip time.
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
1 In
Time t1
Contributes towards calculating the trip time.
The value is given in seconds and can be set within the range: 3 s ..
144 s, in 1 s steps
144 s
Thermal
memory
Activates/deactivates the thermal memory function (page 75)
NOTE : the function is always ON with Ekip M Touch and
available with curve t = k / I
2
for all the other trip unit models
OFF
Prealarm I1
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.
NOTE : the prealarm condition deactivates in two cases:
• current lower than prealarm threshold I1
• current higher than threshold I1
90 % 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 94)
• Time t1 : non-editable; determined by the Trip class (page 71)
•
Thermal memory
: always enabled, functions according to standard IEC 60255-8; thermal memory reset
time is established by the Trip class (page 71)
• 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
• with CB in UL standard configuration, the only available curve is t = k/I
2