Protection G - ABB SACE Emax 2 Series Installation, Operation And Maintenance Instructions

Protection G

t
I4
G
t4
I
41 | © 2013 ABB | 1SDH001000R0002 - L7804
The protection G protects against an earth fault.
NOTE: the protection is available for the LSIG version of the release.
When the activation threshold is exceeded, the protection trips within a fixed or dynamic time
(the time decreases as the current read increases).
Parameters
All the parameters that can be modified by the user affect the response curve, and related
tripping times.
Parameter Description
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 release in two
conditions:
• Disconnection of one or more current sensors.
• Current measured on one of the phases is higher than a maximum
value.
Enabling
IMPORTANT: the maximum current value that deactivates
protection G 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).
Determines the dynamic of the curve and the tripping time, fixed or
dynamic according to the selection:
Type of curve
NOTE: the 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 44.
It defines the current value that if exceeded activates the protection (in
reference to the curve, it is the part parallel to the ordinate).
Threshold (I4)
IMPORTANT: the delay is interrupted if the current drops
below the activation threshold.
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 (in
reference to the curve, t4 affects the entire curve, shifting it as a whole
Time (t4)
along the vertical axis).
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.
ABB | SACE Emax 2
Ekip Dip protection release | 2 - Protections