GE t60 Instruction Manual page 365

5 SETTINGS
INVERSE CURVE B:
The curve for the Volts/Hertz Inverse Curve B shape is derived from the formula:
where: T = Operating Time
TDM = Time Delay Multiplier (delay in sec.)
V = fundamental RMS value of voltage (pu)
F = frequency of voltage signal (pu)
Pickup = volts-per-hertz pickup setpoint (pu)
The volts/hertz inverse B curves are shown below.
Figure 5–130: VOLTS-PER-HERTZ CURVES, INVERSE CURVE B
INVERSE CURVE C:
The curve for the Volts/Hertz Inverse Curve C shape is derived from the formula:
where: T = Operating Time
TDM = Time Delay Multiplier (delay in sec.)
V = fundamental RMS value of voltage (pu)
F = frequency of voltage signal (pu)
Pickup = volts-per-hertz pickup setpoint (pu)
GE Multilin
--------------------------------------------- - when V TDM
T
=
V
  Pickup

--- -
1
–
 
F
Multiples of volts per hertz pickup
TDM
---------------------------------------------------- - when
T
=
0.5
V
  Pickup
--- - 
1
–
 
F
T60 Transformer Protection System
5.6 GROUPED ELEMENTS
--- - 
Pickup
F
Time
delay
setting
830739A1.CDR
V

--- -
Pickup
F
(EQ 5.46)
5
(EQ 5.47)
5-241