5-60 F650 Digital Bay Controller GE Multilin
5.4 PROTECTION ELEMENTS 5 SETPOINTS
5
5.4.6.3 INSTANTANEOUS OVERCURRENT UNIT FOR UNGROUNDED SYSTEMS (50IG)
50IG unit is a protection element for distribution feeders connected to a busbar that is fed by a power transformer in a delta
or wye connection. The operation of this unit is similar to that of sensitive ground overcurrent units; the difference is that in
the case of 50IG, the 3I0 current is capacitive, and uses very reduced magnitudes (0.5-10 A primary values).
The operation characteristic is shown on figure Figure 5–13:, where Vh, Vl, Ih and Il are unit setpoints.
Figure 5–13: OPERATION CHARACTERISTIC FOR UNIT 50IG
Table 5–56: 50IG UNIT SETPOINTS
The relay setpoints for the 50IG elements are as follows:
Function: This setpoint determines whether the unit is operative and can generate pickup and
trip events, which can be configured to close outputs, light up LEDs or trigger
oscillography.
Vh, VL, Ih, IL: Vn and In values that define the points in the operative area.
Operation time (Delay): This is the selectable period between the unit pickup and trip, with a range from 0 to
900 seconds in steps of 0,01 seconds.
Deviation time to Instantaneous (Time to inst): Time after the trip during which the units become instantaneous. It must
be set to zero if the functionality is not required.
Snapshot Events: The snapshot event setpoint enables or disables the snapshot event generation for
this unit.
SETPOINT > PROTECTION ELEMENTS > SENSITIVE GROUND CURRENT > ISOLATED GROUND IOC
ISOLATED GROUND IOC 1> ISOLATED GROUND IOC 2 > ISOLATED GROUND IOC 3
SETPOINT DESCRIPTION NAME DEFAULT VALUE STEP RANGE
Function Permission Function DISABLED N/A [DISABLED – ENABLED]
High Voltage Vh Level 20 1 V [2 : 70]
Low Current Il LEVEL 0.005 0.001 A [0.005 : 0.400]
Low Voltage Vl LEVEL 2 1 V [2 : 70]
High Current Ih LEVEL 0.025 0.001 A [0.005 : 0.400]
Operation time Delay 0.00 0.01 s [0.00 : 900.00]
Deviation time to instantaneous Time to inst 0.00 0.01 s [0.00 : 900.00]
Snapshot event generation Snapshot Events ENABLED N/A [DISABLED – ENABLED]
O
eration Are
I
h
I
l
V
V
h
V
n
=3V
0
I
n
=3I
0
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