GE 745 Instruction Manual page 182

S4 ELEMENTS
5–86
where: T = operate time (in seconds)
D = delay setpoint (in seconds)
V = fundamental RMS value of voltage (V)
F = frequency of voltage signal (Hz)
Pickup = volts per hertz pickup setpoint (V/Hz)
1000
100
10
1
0.1
0.01
1.00
The curve for the inverse curve 2 shape is derived from the formula:
T
where: T = operate time (in seconds)
D = delay setpoint (in seconds)
V = fundamental RMS value of voltage (V)
F = frequency of voltage signal (Hz)
Pickup = volts per hertz pickup setpoint (V/Hz)
1000
100
10
1
0.1
1.00
1.20 1.40 1.60
Multiples of Volts/Hertz Pickup
FIGURE 5–34: Volts per hertz curve 1
D V
------------------------- - -- - >
when Pickup
=
V F ⁄ F
--------------- - 1
–
Pickup
1.20 1.40 1.60
Multiples of Volts/Hertz Pickup
FIGURE 5–35: Volts per hertz curve 2
745 TRANSFORMER PROTECTION SYSTEM – INSTRUCTION MANUAL
CHAPTER 5: SETPOINTS
Time
Delay
Setting
ò
10
3
1
0.3
0.1
1.80 2.00
(EQ 5.13)
Time
Delay
Setting
10
3
1
0.3
0.1
1.80 2.00