GE UR T60 - Page 364

5-226 T60 Transformer Protection System GE Multilin
5.6 GROUPED ELEMENTS 5 SETTINGS
5
INVERSE CURVE B:
The curve for the Volts/Hertz Inverse Curve B shape is derived from the formula:
(EQ 5.46)
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 5–124: 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:
(EQ 5.47)
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)
T
TDM
V
F
--- -


Pickup⁄ 1–
----------------------------------------------
when
V
F
--- -
Pickup>=
Time to trip (in seconds)
Multiples of volts per hertz pickup
830739A1.CDR
Time
delay
setting
T
TDM
V
F
--- -


Pickup⁄
0.5
1–
---------------------------------------------------- -
when
V
F
--- -
Pickup>=