Phase Undervoltage Unit (27P) - GE Multilin F650 Instruction Manual

5 SETPOINTS

5.4.8.1 PHASE UNDERVOLTAGE UNIT (27P)

27P unit is a phase undervoltage protection element that uses as input magnitude the fundamental phasor of phase-to-
phase or phase-to-ground voltage, selectable by setpoint. The unit time delay can be selected between definite time and
inverse time. The unit reset is always instantaneous, that is, when the voltage exceeds the dropout value, the unit is reset.
There is an undervoltage setpoint that allows selection of a voltage level under which the unit will be inhibited. This way, we
can distinguish between a fault condition and a Deadline condition where VTs are located in front of the breaker, and when
it is open, the relay loses the voltage values. By setpoint this level to 0 we make this element operate every time the voltage
value is lower than the setpoint. This unit generates independent pickup and trip signals per phase, and general pickup and
trip signals for the unit. These last signals can be selected, by means of the operation logic setpoint, to be an OR (any
phase signal) or an AND (all phase signals).
Table 5–59: 27P UNIT SETPOINTS
SETPOINT > PROTECTION ELEMENTS > VOLTAGE ELEMENTS > PHASE UV >
PHASE UV 1> PHASE UV 2 > PHASE UV 3
SETPOINT DESCRIPTION
Function permission
Input mode
Pickup Level
Curve shape
Time Dial
Minimum Voltage Threshold
Operation logic
Supervision by breaker status
Snapshot Event generation
Phase undervoltage unit setpoints are:
Function Permission (Function):This setpoint indicates whether the phase undervoltage element is enabled or disabled.
Input mode (Mode):
Pickup Level:
Curve Shape (Curve):
Time Dial (Delay):
Minimum voltage Threshold (Minimum Voltage):Voltage setpoint under which the undervoltage element in inhibited, in
Operation logic (Logic):
Supervision by breaker status (Supervised by 52):This setpoint allows inhibiting the undervoltage element if the
Snapshot Events:
GE Multilin
NAME DEFAULT
VALUE
Function DISABLED
Mode PHASE-PHASE
Pickup Level 10
Curve DEFINITE TIME
Delay 10.00
Minimum Voltage 0
Logic ANY PHASE
Supervised by 52 DISABLED
Snapshot Events ENABLED
This setpoint allows selecting operation for phase-to-phase or phase-to-ground voltage,
depending on the selected setpoint.
This is the voltage threshold under which the undervoltage unit will operate.
Undervoltage elements can be set to operate with definite time or with an inverse time
curve. Units set as definite time operate when the voltage value remains under the
pickup setpoint during the set time. If inverse time is selected, the unit will operate
according the previously described inverse time curve.
setpoint of the Protection element operation time.
order not to operate in deadline cases.
This setpoint allows the unit operation logic selection:
ANY PHASE The unit will operate under an undervoltage condition in any of the three
phases.
TWO PHASES The unit will operate under an undervoltage condition in at least two
phases.
ALL PHASES The unit will operate under an undervoltage condition in the three
phases.
breaker is open breaker. In case this setpoint is enabled, the undervoltage element will
be supervised by the breaker status. Otherwise, the element will operate independently
of the breaker status.
The snapshot event setpoint enables or disables the snapshot event generation for this
unit.
F650 Digital Bay Controller
5.4 PROTECTION ELEMENTS
STEP RANGE
N/A [DISABLED – ENABLED]
N/A [PHASE-PHASE, PHASE-GROUND]
1 V [3 : 300]
N/A [DEFINITE TIME – INVERSE TIME]
0.01 s [0.00 : 900.00]
1 V [0 : 300]
N/A [ANY PHASE – TWO PHASES – ALL PHASES]
N/A [DISABLED – ENABLED]
N/A [DISABLED – ENABLED]
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