Volts/Hertz; Phase Reversal - GE 489 Instruction Manual

4.7 S6 VOLTAGE ELEMENTS
The formula for volts/hertz curve 2 is:
D
T = ------------------------------------------------------------- -
V F ⁄
---------------------------------------------------- - 1
( ⁄ ) ×
V F Pickup
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 2 trip curves are shown on the right
for delay settings of 0.1, 0.3, 1, 3, and 10 seconds.
4
The formula for volts/hertz curve 3 is:
D
T
= ------------------------------------------------------------------------- -
V F ⁄

---------------------------------------------------- -

( ⁄ ) Pickup ×
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 on the right
for delay settings of 0.1, 0.3, 1, 3, and 10 seconds.
Volts/Hertz is calculated per unit as follows:
NOTE
T

PHASE REVERSAL

T
[ENTER] for more
The 489 can detect the phase rotation of the three phase voltages. A trip will occur within 200 ms if the Phase Reversal fea-
ture is turned on, the generator is offline, each of the phase-phase voltages is greater than 50% of the generator rated
phase-phase voltage and the phase rotation is not the same as the setpoint. Loss of VT fuses cannot be detected when the
generator is offline and could lead to maloperation of this element. If the VT type is selected as "None", the phase reversal
protection is disabled.
4-32
V
>
, when --- - Pickup
F
–
setpoint
setpoint
V
>
, when --- - Pickup
 0.5 F
– 1

setpoint
setpoint

Volts/Hertz

ð
PHASE REVERSAL
ENTER
TRIP: Off
ESCAPE
ASSIGN TRIP
ESCAPE
RELAYS (1-4): 1---
MESSAGE
489 Generator Management Relay
1000
100
10
1
0.1
1.00 1.20 1.40
Multiples of Volts/Hertz Pickup
10000
1000
100
10
1
0.1
1.00 1.20 1.40
Multiples of Voltz/Hertz Pickup
phase-phase voltage rated phase-phase voltage
= ----------------------------------------------------------------------------------------------------------------------------------
frequency rated frequency
Range: Off, Latched, Unlatched
Range: Any combination of Relays 1 to 4
4 SETPOINT PROGRAMMING
10
3
1
0.3
0.1
1.60 1.80 2.00
10
3
1
0.3
0.1
1.60 1.80 2.00
⁄
⁄
4.7.4 PHASE REVERSAL
GE Power Management