Volts/Hertz - GE 489 Instruction Manual

4 SETPOINTS
PATH: SETPOINTS S6 VOLTAGE ELEMENTS

VOLTS/HERTZ

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The Volts/Hertz elements may be used generator and unit transformer protection. They are active as soon as the magni-
tude and frequency of V is measurable. The alarm element is definite time; the trip element can be definite time or a
ab
curve. Once the V/Hz measurement V
rate is a linear reset time from the threshold of trip and should be set to match cooling characteristics of the protected
equipment. The measurement of V/Hz will be accurate through a frequency range of 5 to 90 Hz. Settings less than 1.00
only apply for special generators such as short circuit testing machines.
The formula for Volts/Hertz Curve 1 is:
D
T ----------------------------------------------------------------------
=
V F ⁄
⎛ ⎞ 2
---------------------------------------------------- -
⎝ ⎠
( ⁄ ) 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 1 trip curves are shown on the right
for delay settings of 0.1, 0.3, 1, 3, and 10 seconds.
GE Multilin
VOLTS/HERTZ
ð
VOLTS/HERTZ
ENTER
ð
ESCAPE ALARM: Off
ASSIGN ALARM
ESCAPE
RELAYS (2-5): ---5
MESSAGE
VOLTS/HERTZ ALARM
ESCAPE
PICKUP: 1.00 x Nominal
MESSAGE
VOLTS/HERTZ ALARM
ESCAPE
DELAY: 3.0 s
MESSAGE
VOLTS/HERTZ ALARM
ESCAPE
EVENTS: Off
MESSAGE
VOLTS/HERTZ
ESCAPE
TRIP: Off
MESSAGE
ASSIGN TRIP
ESCAPE
RELAYS (1-4): 1---
MESSAGE
VOLTS/HERTZ TRIP
ESCAPE
PICKUP: 1.00 x Nominal
MESSAGE
VOLTS/HERTZ TRIP
ESCAPE
DELAY: 1.0 s
MESSAGE
VOLTS/HERTZ CURVE
ESCAPE
RESET RATE: 1.4 s
MESSAGE
VOLTS/HERTZ TRIP
ESCAPE
ELEMENT: Curve #1
MESSAGE
exceeds the pickup level for the specified time, a trip or alarm will occur. The reset
ab
V
--- - >
, when Pickup
F
1
–
setpoint
setpoint
489 Generator Management Relay
4.7 S6 VOLTAGE ELEMENTS
Range: Off, Latched, Unlatched
Range: Any combination of Relays 2 to 5
Range: 0.50 to 1.99 × Nominal in steps of 0.01
Range: 0.1 to 150.0 s in steps of 0.1
Range: On, Off
Range: Off, Latched, Unlatched
Range: Any combination of Relays 1 to 4
Range: 0.50 to 1.99 × Rated in steps of 0.01
Range: 0.1 to 150.0 s in steps of 0.1
Range: 0.0 to 999.9 s in steps of 0.1
Range: Curve #1, Curve #2, Curve #3, Definite Time
1000
100
10
1
0.1
0.01
1.00 1.20 1.40
Multiples of Volts/Hertz Pickup
4.7.3 VOLTS/HERTZ
10
3
1
0.3
0.1
1.60 1.80 2.00
808743A1-X1.CDR
4-35
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