Page 25 - Sace Emax 2 Manual for design engineers

ABB | SACE Emax 2
G Protection G protection protects against a ground fault.
NOTE: the protection is available for the LSIG version of the trip unit.

t I4 G When the activation threshold is exceeded, the protection trips within a fixed or dynamic time (the time
decreases as the current reading increases).
Parameters
t4 All the parameters that can be modified by the user affect the response curve, and related tripping times.

Parameter Description
I By setting the dip-switches of the threshold in one of the available combinations
other than Off, the protection is enabled.
If enabled, the protection is inhibited automatically by the trip unit under two
conditions:
• Disconnection of one or more current sensors.
• Current measured on one of the phases higher than a maximum value.
Enable
IMPORTANT: the maximum current value that deactivates G protection
varies according to the threshold set:
• 8 In (with I4 ≥ 0.8 In)
• 6 In (with 0.5 In ≤ I4 < 0.8 In)
• 4 In (with 0.2 In ≤ I4 < 0.5 In)
• 2 In (with I4 < 0.2 In)
It determines the dynamic of the curve and the tripping time, fixed or dynamic
according to the selection:
Type of curve
NOTE: calculation of the tripping time of the inverse time curve is based on a
mathematical expression. The details are provided in the table on page 26.
It defines the current value that activates the protection when exceeded (with
reference to the curve, it is the part parallel to the y-axis).
IMPORTANT:
Threshold I4 • The delay is interrupted if the current drops below the tripping
threshold.
• For all the UL versions the maximum threshold allowed by the trip
unit is 1200 A. If a higher value is set, the trip unit signals the error and
forces the parameter to 1200 A.
The selected function determines the contribution of t4:
• Fixed time: t4 is the delay time between the exceeding of the I4 threshold and the
sending of the opening command.
• Dynamic time: t4 contributes in calculating the tripping time (with reference to the
curve, t4 affects the entire curve, shifting it as a whole along the y-axis).
Time t4
IMPORTANT:
• The minimum tripping time of the protection is t4. If, according to
the calculation, the tripping time is less, it is automatically limited to t4.
• For all the UL versions, the maximum time allowed by the trip unit
is 0.4s. If a higher value is set, the trip unit signals the error and forces the
parameter to 0.4 s.

With the Ekip T&P module and with the Ekip Connect software it is possible to adjust the threshold of Pre-
alarm.

23 | © 2020 ABB | 1SDH001330R1002 - ECN000134959 - Rev. A Ekip Dip | 1 - Protections - Introduction