Instantaneous Overcurrent Unit For Ungrounded Systems (50Ig); Operation Characteristic For Unit 50Ig - GE Multilin F650 Instruction Manual

5.4 PROTECTION ELEMENTS

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.
5
Table 5–56: 50IG UNIT SETPOINTS
SETPOINT > PROTECTION ELEMENTS > SENSITIVE GROUND CURRENT > ISOLATED GROUND IOC
ISOLATED GROUND IOC 1> ISOLATED GROUND IOC 2 > ISOLATED GROUND IOC 3
SETPOINT DESCRIPTION
Function Permission
High Voltage
Low Current
Low Voltage
High Current
Operation time
Deviation time to instantaneous
Snapshot event generation
The relay setpoints for the 50IG elements are as follows:
Function:
Vh, VL, Ih, IL:
Operation time (Delay):
Deviation time to Instantaneous (Time to inst): Time after the trip during which the units become instantaneous. It must
Snapshot Events:
5-60
V =3V
n 0
V
h
V
l
I
l
Figure 5–13: OPERATION CHARACTERISTIC FOR UNIT 50IG
NAME
Function
Vh Level
Il LEVEL
Vl LEVEL
Ih LEVEL
Delay
Time to inst
Snapshot Events
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.
Vn and In values that define the points in the operative area.
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.
be set to zero if the functionality is not required.
The snapshot event setpoint enables or disables the snapshot event generation for
this unit.
F650 Digital Bay Controller
Operation Area
I
h
DEFAULT VALUE STEP
DISABLED N/A
20 1 V
0.005 0.001 A
2 1 V
0.025 0.001 A
0.00 0.01 s
0.00 0.01 s
ENABLED N/A
5 SETPOINTS
I =3I
n 0
RANGE
[DISABLED – ENABLED]
[2 : 70]
[0.005 : 0.400]
[2 : 70]
[0.005 : 0.400]
[0.00 : 900.00]
[0.00 : 900.00]
[DISABLED – ENABLED]
GE Multilin