Phase Reversal - GE Multilin 489 Instruction Manual

Note
5.7.4

Phase Reversal

1 PHASE
REVERSAL
5–48
Courtesy of NationalSwitchgear.com
The formula for Volts/Hertz Curve 3 is:
T
---------------------------------------------------------------------- -
=
V F ⁄
⎛
------------------------------------------------- -
⎝
( V ⁄ F
nom s
where: T = trip time in seconds
D =
VOLTS/HERTZ TRIP DELAY
V = RMS measurement of Vab
F = frequency of Vab
V = generator voltage setpoint
NOM
F = generator frequency setpoint
S
Pickup =
VOLTS/HERTZ TRIP PICKUP
The V/Hz Curve 3 trip curves are shown below for delay settings of 0.1, 0.3, 1, 3, and 10
seconds.
10000
1000
100
10
1
0.1
1.00
Volts/Hertz is calculated per unit as follows:
phase-phase voltage rated phase-phase voltage
Volts/Hertz
---------------------------------------------------------------------------------------------------------------------------- -
=
frequency rated frequency
PATH: SETPOINTS S6 VOLTAGE ELEM.
[ ] PHASE REVERSAL
TRIP: Off
ASSIGN TRIP
MESSAGE
RELAYS (1-4): 1---
The 489 can detect the phase rotation of the three phase voltages. A trip will occur within
200 ms if the Phase Reversal feature is turned on, the generator is offline, each of the
phase-phase voltages is greater than 50% of the generator rated phase-phase voltage
D
V
, when -- - >
F
0.5
⎞
1
–
⎠
) × Pickup
setpoint
setpoint
1.20 1.40 1.60
Multiples of Voltz/Hertz Pickup
⁄
⁄
PHASE REVERSAL
Range: Off, Latched, Unlatched
Range: Any combination of Relays 1 to
489 GENERATOR MANAGEMENT RELAY – INSTRUCTION MANUAL
CHAPTER 5: SETPOINTS
Pickup
(EQ 5.22)
10
3
1
0.3
0.1
1.80 2.00
808743A1-X3.CDR
4