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M-3520 Instruction Book
51G Inverse Time Neutral Overcurrent
Neutral Inverse Time Overcurrent relay is used to
trip circuits selectively for ground faults, and to time
coordinate with up or down stream relays. For this
function, eight complete series of inverse time
characteristics are included. The eight curve families
to be chosen are definite, inverse, very inverse,
extremely inverse, and four IEC curves. The
operator selects the time dial within each family
setting and pickup setting through the M-3520 menu.
The curves available for use are shown in Appendix
D, Figures D-1 through D-8. They cover a range
from 1.5 to 20 times the pickup. For currents beyond
20 times the pickup setting, the relay operating time
will remain the same as the time at 20 times the
pickup setting.
Save
Cancel
@ : WARNING, Function DISABLED until output selected!
(51G) - INVERSE TIME NEUTRAL OVERCURRENT
Pickup:
Delay:
#1
0.25 Amp
0.5
12.00 Amps
11.0
OUTPUT
8
7
6
5
4
3
2
1
FL
6
5
4
3
2
1
Blocking Input
@
Curves
Definite Time
IECI
Inverse
IECVI
Very Inverse
IECEI
Extremely Inverse
IECLTI
Ground Directional Element
Enable
Disable
Figure 2-18
M-3822 IPScom® for Windows™ Inverse Time Neutral Overcurrent (51G) Setpoint
Ranges
Path
: Relay Menu/Setup/Setpoints/(51G) Inverse Time Neutral Overcurrent
COMMAND BUTTONS
Save
Saves all information to the relay.
Cancel
Returns the user to the previous window; any changes to the displayed information are lost.
Sets ground current pickup.
Selects one of the eight inverse time curves as shown in
Appendix D, Figures D-1 through D-8.
The appropriate curve in the selected family of curves is
chosen here.
51G may be directionally controlled. See 67N function for
maximum sensitivity angle and polarization setup.
51G PICKUP
________ Amps
51G CURVE
DEF inv vinv einv
51G TIME DIAL
________
DIRECTIONAL ELEMENT
disable ENABLE
If this function is enabled, the following settings are applicable:
Summary of Contents for M-3520
Page 1: ...Instruction Book M 3520 Intertie Protection Relay ...
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