GE 850 Instruction Manual page 357

CHAPTER 6: PROTECTION SETPOINTS
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850 FEEDER PROTECTION SYSTEM – INSTRUCTION MANUAL
PICKUP
Range: 0.00 to 1.50 x VT in steps of 0.01 x VT
Default: 0.90 x VT
This setting sets the phase Undervoltage pickup level specified as percent VT. For
example, a Pickup setting of 0.90xVT with 13800:115 VT translates into 12.42kV (or
103.5V secondary). If the Mode selection is Phase to Phase and Setpoints/ System Setup/
Voltage Sensing/ Phase VT Connection selection is Wye, the previous example will
translate to the Phase to Phase voltage value of 12.42kV x 1.732 = 21.51kV.
DROPOUT
Range: 102.00 to 150.00 %PKP in steps of 0.001 %PKP
Default: 102.00 %PKP
This setting sets the phase Undervoltage dropout level specified as a percentage of
Pickup. For example, a Dropout setting of 102 %PKP with 0.90 x VT as pickup and
13800:115 VT translates into 1.02 x 12.42kV = 12.67kV (or 105.57V secondary). If the
Mode selection is Phase to Phase and Setpoints/System Setup/Voltage Sensing/Phase
VT Connection selection is Wye, the previous example will translate to the Phase to
Phase voltage value of 12.67kV x 1.732 = 21.94kV.
DROPOUT DELAY
Range: 0.000 to 6000.000 s in steps of 0.001 s
Default: 0.000 s
This setting provides a definite time dropout delay. Instantaneous operation is selected
by a dropout time delay setting of 0.000 s.
MINIMUM VOLTAGE
Range: 0.00 to 1.50 x VT in steps of 0.01 x VT
Default: 0.20 x VT
This setting sets the minimum operating voltage for undervoltage pickup level specified
as percent of VT. For example, a minimum voltage setting of 0.20x VT with 13800:115 VT
translates into 2.76kV (or 23V secondary). If the Mode selection is Phase to Phase and
Setpoints/ System Setup/ Voltage Sensing/ Phase VT Connection selection is Wye, the
previous example will translate to a Phase to Phase voltage value of 2.76kV x 1.732 =
4.78kV.
COUNTER MODE
Range: Disabled, Enabled
Default: Disabled
This setpoint enables the counter based undervoltage protection. With this setting
enabled, define the number of tolerated voltage drops and the total time window for
which these voltage drops are allowed.
VOLTAGE DROPS
Range: 1 to 10 in steps of 1
Default: 2
This setpoint indicates the number of transient voltage drops the relay can tolerate
within the time allocated for the voltage drops. If the number of transient voltage drops
exceeds the defined setting within the time defined for the voltage drops, a trip is issued.
This setting can be coordinated with recloser shot settings.
This setting is only functional if the Counter Mode setting is set to Enabled.
VOLTAGE ELEMENTS
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