GE TRANSFORMER MANAGEMENT RELAY 745 Instruction Manual page 126

5.6 S4 ELEMENTS
The curve for the Inverse Curve 1 shape is derived
from the formula:
D
T -----------------------------------
=
V F ⁄ 2
 
----------------- -
1
–
 
Pickup
where T = operate time (seconds)
D = delay setpoint (seconds)
V = fundamental RMS value of voltage (V)
F = frequency of voltage signal (Hz)
Pickup = volts-per-hertz pickup setpoint (V/Hz)
The curve for the inverse curve 2 shape is derived
from the formula:
D
T
-------------------------- -
=
V F ⁄
----------------- - 1
–
Pickup
5
where T = operate time (seconds)
D = delay setpoint (seconds)
V = fundamental RMS value of voltage (V)
F = frequency of voltage signal (Hz)
Pickup = volts-per-hertz pickup setpoint (V/Hz)
The curve for the inverse curve 3 shape is derived
from the formula:
D
T -------------------------------------- -
=
V F ⁄ 0.5
 
----------------- -
1
–
 
Pickup
where T = operate time (seconds)
D = delay setpoint (seconds)
V = fundamental RMS value of voltage (V)
F = frequency of voltage signal (Hz)
Pickup = volts-per-hertz pickup setpoint (V/Hz)
5-76
Courtesy of NationalSwitchgear.com
V
--- - >
when Pickup
(EQ 5.12)
F
V
>
when --- - Pickup
(EQ 5.13)
F
V
--- - >
when Pickup
(EQ 5.14)
F
745 Transformer Management Relay
1000
100
10
1
0.1
0.01
1.00 1.20 1.40
Multiples of Volts/Hertz Pickup
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
5 SETPOINTS
Time
Delay
Setting
ò
10
3
1
0.3
0.1
1.60 1.80 2.00
Time
Delay
Setting
10
3
1
0.3
0.1
1.60 1.80 2.00
Time
Delay
Setting
ò
10
3
1
0.3
0.1
1.60 1.80 2.00
GE Multilin