ABB SACE Tmax XT7 Operation And Maintenance Manual page 53

IU Protection
t
I6
Neutral Protection Function
51 | © 2020 ABB | 1SDH001821A1002 - ECN000135670
Function
The protection trips if the current readings are unbalanced; the protection sends a TRIP command if the
detected unbalance exceeds threshold I6 for longer than t6.
IU
The protection is automatically self-excluding in two cases:
• the measurement of at least one current exceeds 6 In
• the maximum current among all the phases is less than 0.3 In
t6
To check and simulate the trip times in relation to all the parameters, please consult:
• summary table of the protections with the operating characteristics (page 87)
I
• the graph with trip curve (page 99)
Parameters
Parameter Description
Enable Activates/deactivates the protection and its availability in the parameters menu OFF
Activates/deactivates transmission of the open command: if disabled, the
Trip Enable
alarm and exceedance of protection time are only managed as information
Allows the unbalance calculation mode to be selected:
• Old: % Sbil = 100 x (I
• New: % Sbil = 100 x (Δmax I
Version
Establishes the unbalance value that trips the protection.
Threshold I6 Unbalance is given in percentage value within the range: 2% to 90% with 1%
steps.
This is the trip time of the protection; the value is given in seconds and can be
Time t6
set within a range: 0.5 s to 60 s, in 0.5 s steps
Ekip M Touch
With Ekip M Touch, IU protection features the following differences compared to the other models:
• version set as New, non-editable
• protection is inhibited if the rms value of at least one of the phase currents is less than 0.25 In.
Neutral protection characterizes protections L, S and I differently on the neutral phase by introducing a
different control factor from the other phases.
The protection is available with the 4P and 3P + N configuration; the configuration parameters can be
accessed via the Settings menu (page 37).
Parameters
Parameter Description
Enable Activates/deactivates the protection
Defines the multiplicative factor applied to the trip thresholds and curves of
the protections for the current read on phase Ne:
Neutral
threshold
Limitations and additional functions
Ekip Touch rejects modification of thresholds I1 and InN in the absence of the following limitation: (I1 x InN)
≤ Iu
• I1 is the threshold of L protection in Amperes (example: In= 800 A and I1= 0.6 becomes I1= 480 A)
• InN is the neutral threshold expressed as multiplicative factor (example: InN= 200% becomes InN= 2)
• Iu is the size of the CB
WARNING! With 150% and 200% threshold; if the measured neutral current exceeds
16In, the Trip unit resets the protection to 100% by itself
- I ) / I
max min
) / I
mi
NOTE:Δmax I : maximum deviation among the measured currents,
mi
calculated by comparing each current with the mean value;
I : mean value of the current readings
mi
• 50 %: lowest trip thresholds for the neutral current
• 100 %: same trip thresholds for all phases
• 150 %: highest trip thresholds for the neutral current
• 200 %: highest trip thresholds for the neutral current
max
mi
Protections | 7 - Standard Protections
ABB | SACE Tmax XT
Default
OFF
Old
50 %
5 s
Default
OFF
50 %