ABB SACE Tmax XT5 Operation And Maintenance Manual page 46

G Protection
t
I4
t4
44 | © 2019 ABB | 1SDH002039A1002 - ECN000093027 - Rev. A
Function
Ekip Touch calculates the vector sum of the phase currents (L1, L2, L3, Ne) and obtains the internal earth
fault current (Ig): if current Ig exceeds threshold I4, the protection trips and, after a time established by the
G
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 79)
• the graph with trip curve (page 87)
Parameters
I
Parameter Description
Activates/deactivates the protection and its availability in the
Enable
parameters menu.
Activates/deactivates transmission of the open command. if disabled,
Trip Enable the alarm and exceedance of protection time are only managed as
information.
Establishes curve dynamics and the threshold or trip time calculation:
Curve
Establishes the value that activates the protection and contributes
towards calculating the trip time.
Threshold I4
The value is given as both absolute value (A) and relative value (In) and
can be set within the range: 0.1 In to 1 In, in 0.001 In steps
It is the trip time or contributes towards timing calculation, depending
on the type of curve selected.
The value is given in seconds and can be set within the range: 0.1 s to
Time t4 1 s, in 0.05 s steps
Warns that the measured current is near to the protection activation
threshold.
The value is given in percentage of threshold I1 and can be set within
Prealarm I4 the range 50% I4 to 90% I4, in 1% steps.
The prealarm condition deactivates in two cases:
Activates/deactivates the function and selectivity time availability on
the display (page 72)
ZoneSelectivity
This is the trip time of the protection with the zone selectivity function
activated and selectivity input not present (page 72)
Selectivity time
The value is given in seconds and can be set within the range: 0.04 s
to 0.2 s, in 0.01 s steps
Activates/deactivates the function and availability of the associated
StartUp enable
parameters on the display (page 75)
Protection threshold valid during Startup time, in the conditions in
StartUp which the function is activated (page 75)
Threshold The value is given as both absolute value (A) and relative value (In) and
can be set within the range: 0.2 In to 1 In, in 0.1 In steps
This is the time for which the StartUp threshold remains activated,
as calculated from the moment the activation Threshold is exceeded
StartUp Time (page 75)
The value is given in seconds and can be set within the range: 0.1 s to
30 s, in 0.01 s steps
• t = k: fixed time trip
• t = k/I : inverse time-delay dynamic trip
2
NOTE: in the presence of curve: t = k, t4 can also be configured
as: instantaneous; in this mode, the trip time is comparable to
that given for I protection (page 79)
• current lower than prealarm threshold I4
• current higher than threshold I4
NOTE: the function is only available with curve t = k
ABB | SACE Tmax XT
Default
OFF
ON
t = k
0,2 In
0,4 s
90 % I4
OFF
0,04 s
OFF
0,2 In
0.1 s
Continued on the next page
Protections | 1 - Standard Protections