Underfrequency Unit (81U); Overfrequency Unit (81O) - GE Multilin F650 Instruction Manual

5.5 CONTROL ELEMENTS
Setpoint >Control Elements > Underfrequency
The 81U unit is an underfrequency control element. The pickup setpoint can be selected from 20.00 to 65.00 Hz, allowing
its use as load shedding unit. The unit reset time delayed is selectable between 0.00 and 900 seconds, and for the unit to
operate it is necessary that the voltage value is over the value set for minimum voltage threshold. This way undesired trips
are prevented when the signal for metering the frequency is not available or has a very low value.
Table 5–69: 81U UNIT SETPOINTS
SETPOINT > CONTROL ELEMENTS > UNDERFREQUENCY
UNDERFREQUENCY 1 > UNDERFREQUENCY 2 > UNDERFREQUENCY 3
SETPOINT DESCRIPTION
Function permission
Pickup level
Trip time
Reset time
Minimum voltage threshold
Snapshot event generation
The snapshot event setpoint enables or disables the snapshot event generation for this unit.
Frequency elements operate with the system frequency, this frequency is measured in the voltage channel set for the
5
frequency reference, in the Frequency Reference setpoint inside Setpoint > System Setup >General setpoints.
Setpoint >Control Elements > Overfrequency
The 81O unit is an overfrequency protection element. The pickup setpoint can be selected from 20.00 to 65.00 Hz, with a
time delay selectable between 0 and 900 seconds. The unit-reset delay is from 0.00 to 900.00 seconds.
Table 5–70: 81O UNIT SETPOINTS
SETPOINT > CONTROL ELEMENTS > OVERFREQUENCY
OVERFREQUENCY 1 > OVERFREQUENCY 2 > OVERFREQUENCY 3
SETPOINT DESCRIPTION
Function permission
Pickup level
Trip time
Reset time
Minimum voltage threshold
Snapshot event generation
The snapshot event setpoint enables or disables the snapshot event generation for this unit.
5-78
NAME DEFAULT VALUE
Function DISABLED
Pickup Level 49.50
Trip Delay 0.00
Reset Delay 0.00
Minimum Voltage 30
Snapshot Events ENABLED
NAME DEFAULT VALUE
Function DISABLED
Pickup Level 50.50
Trip Delay 0.00
Reset Delay 0.00
Minimum Voltage 30
Snapshot Events ENABLED
F650 Digital Bay Controller
5 SETPOINTS

5.5.2 UNDERFREQUENCY UNIT (81U)

STEP RANGE
N/A [DISABLED – ENABLED]
0.01 Hz [20.00 : 65.00]
0.01 s [0.00 : 900.00]
0.01 s [0.00 : 900.00]
1 V [30 : 300]
N/A [DISABLED – ENABLED]

5.5.3 OVERFREQUENCY UNIT (81O)

STEP RANGE
N/A [DISABLED – ENABLED]
0.01 Hz [20.00 : 65.00]
0.01 s [0.00 : 900.00]
0.01 s [0.00 : 900.00]
1 V [30 : 300]
N/A [DISABLED – ENABLED]
GE Multilin