ABB SACE Tmax XT7 Operation And Maintenance Manual page 66

D Protection
t
I7
t7bw
64 | © 2020 ABB | 1SDH001821A1002 - ECN000135670
Function
D protection is very similar to S protection, with the additional capability of recognizing the direction of the
current during a fault.
D
The current direction allows the user to find out whether the fault is on the supply side or load side of the
device controlled by Ekip Touch.
In ring type distribution systems, D protection allows the distribution section in which the fault has occurred
t7fw
to be identified and disconnected without affecting the rest of the installation (using zone selectivity).
Depending on the direction of the fault, if the current of one or more phases exceeds threshold I7 (I7fw or
I
I7bw) for longer than time t7 (t7fw or t7bw), the protection activates and sends a TRIP command.
The fault direction is established by comparing the detected fault current with the reference direction.
NOTE: the reference direction is calculated considering the set value of the power flow
direction and the phase sequence (cyclic direction of the phases):
Phase sequence (set) Power flow (set)
123
123
123
123
321
321
321
321
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 88)
• the graph with trip curve (page 103)
Parameter
Enable
Trip Enable
Threshold I7 Fw
Threshold i7 Bw
Time t7 Fw
Time t7 Bw
ZoneSelectivity
(1)
Selectivity t
ime Fw
(1)
Selectivity
time Bw
(1)
High-->Low
Bottom --> Top
High-->Low
Bottom --> Top
High-->Low
Bottom --> Top
High-->Low
Bottom --> Top
Description
Activates/deactivates the protection and its availability in the parameters
menu
Activates/deactivates transmission of the open command: if disabled, the
alarm and exceedance of protection time are only managed as information
Establishes the value that activates the protection with forward direction.
The value is given as both absolute value (Amperes) and relative value (In)
and can be set within the range: 0.6 In to 10 In, in 0.1 In steps
Establishes the value that activates the protection with backward direction.
The value is given as both absolute value (Amperes) and relative value (In)
and can be set within the range: 0.6 In to 10 In, in 0.1 In steps
This is the trip time in the case of forward direction.
The value is given in seconds and can be set within the range: 0.1 s to 0.8
s, in 0.01 s steps
This is the trip time in the case of backward direction.
The value is given in seconds and can be set within the range: 0.1 s to 0.8
s, in 0.01 s steps
Activates/deactivates the function and selectivity time availability on the
display.
NOTE: configure selectivities S, S2, I, 2I, MCR, G, Gext and MDGF
OFF to ensure that selectivity D functions correctly
This is the trip time of the protection with the zone selectivity function
activated, forward direction and selectivity input Fw not present.
The value is given in seconds and can be set within the range: 0.1 s to 0.8
s, in 0.01 s steps
This is the trip time of the protection with the zone selectivity function
activated, backward direction and selectivity input Bw not present.
The value is given in seconds and can be set within the range: 0.1 s to 0.8
s, in 0.01 s steps
Phase sequence Reference direction
(detected) (forward direction)
123 High-->Low
123 Bottom --> Top
321 Bottom --> Top
321 High-->Low
123 Bottom --> Top
123 High-->Low
321 High-->Low
321 Bottom --> Top
Protections | 11 - Power protections
ABB | SACE Tmax XT
Default
OFF
ON
4 In
4 In
0,2 s
0,2 s
OFF
0,13 s
0,13 s
Continued on the next page