GE UR T60, Instruction Manual

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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
>
=
Ti
me
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
>
=