Page 75 - Sace Emax 2 Manual for design engineers

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ABB | SACE Emax 2
D Protection Function
D protection is very similar to S protection, with the additional capability of recognizing the direction of the
t current during a fault.
I7 D The current direction allows the user to find out whether the fault is on the supply side or load side of the
t7bw device controlled by Ekip Touch.
t7fw In ring type distribution systems, D protection allows the distribution section in which the fault has occurred
to be identified and disconnected without affecting the rest of the installation (using zone selectivity).
I Depending on the direction of the fault, if the current of one or more phases exceeds threshold I7 (I7fw or
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 Reference direction
Phase sequence (set) Power flow (set)
(detected) (forward direction)
123 High-->Low 123 High-->Low
123 Bottom --> Top 123 Bottom --> Top
123 High-->Low 321 Bottom --> Top
123 Bottom --> Top 321 High-->Low
321 High-->Low 123 Bottom --> Top
321 Bottom --> Top 123 High-->Low
321 High-->Low 321 High-->Low
321 Bottom --> Top 321 Bottom --> Top

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 93)
• the graph with trip curve (page 106)
Parameter Description Default
Activates/deactivates the protection and its availability in the parameters
Enable OFF
menu
Activates/deactivates transmission of the open command: if disabled, the
Trip Enable ON
alarm and exceedance of protection time are only managed as information
Establishes the value that activates the protection with forward direction.
Threshold I7 Fw The value is given as both absolute value (Amperes) and relative value (In) 4 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.
Threshold i7 The value is given as both absolute value (Amperes) and relative value (In) 4 In
Bw
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.
Time t7 Fw The value is given in seconds and can be set within the range: 0.1 s to 0.8 0,2 s
s, in 0.01 s steps
This is the trip time in the case of backward direction.
Time t7 Bw The value is given in seconds and can be set within the range: 0.1 s to 0.8 0,2 s
s, in 0.01 s steps
Activates/deactivates the function and selectivity time availability on the
ZoneSelectivity display.

(1) NOTE: configure selectivities S, S2 OFF to ensure that selectivity D OFF
functions correctly, G, Gext and MDGF
This is the trip time of the protection with the zone selectivity function
Selectivity time activated, forward direction and selectivity input Fw not present. 0,13 s
Fw (1) 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
Selectivity time activated, backward direction and selectivity input Bw not present. 0,13 s
Bw (1) 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

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