ABB | SACE Emax 2
40 | © 2017
ABB |
1SDH000999R0002 - ECN000058721 - Rev. B
Ekip Dip protection trip unit | 2 - Protections
G Protection
G
I4
t
t4
I
The G protection protects against an ground fault.
NOTE:
the protection is available for the LSIG version of the trip unit.
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
Enable
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 in two conditions:
• Disconnection of one or more current sensors.
• Current measured on one of the phases is higher than a maximum value.
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)
Type of curve
It determines the dynamic of the curve and the tripping time, fixed or dynamic
according to the selection:
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 43.
Threshold I4
It defines the current value that if exceeded activates the protection (with reference
to the curve, it is the part parallel to the y-axis).
IMPORTANT:
•
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.
Time t4
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).
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 or Ekip Bluetooth modules and with the Ekip Connect software, it is possible to adjust the
threshold of
Pre-alarm
. See page 42.
