GE t60 Instruction Manual page 333

5 SETTINGS
The element has a linear reset characteristic. The reset time can be programmed to match the cooling characteristics of the
protected equipment. The element will fully reset from the trip threshold in
may be used as an instantaneous element with no intentional time delay or as a Definite or Inverse timed element.
The characteristics of the inverse curves are shown below.
• DEFINITE TIME: T(sec.) = TD Multiplier. For example, setting the TD Multiplier set to 20 means a time delay of 20 sec-
onds to operate, when above the Volts/Hz pickup setting. Instantaneous operation can be obtained the same way by
setting the TD Multiplier to "0".
• INVERSE CURVE A:
The curve for the Volts/Hertz Inverse Curve A shape is
derived from the formula:
TDM
T ------------------------------------------------ - when
=
2
⎛ ⎞ Pickup
V
⁄
--- -
– 1
⎝ ⎠
F
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)
• INVERSE CURVE B:
The curve for the Volts/Hertz Inverse Curve B shape is
derived from the formula:
TDM
T --------------------------------------------- - when
=
⎛ ⎞ Pickup
V
⁄
--- -
– 1
⎝ ⎠
F
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)
• INVERSE CURVE C:
The curve for the Volts/Hertz Inverse Curve C shape is
derived from the formula:
TDM
T ---------------------------------------------------- - when
=
0.5
⎛ ⎞ Pickup
V
⁄
--- -
– 1
⎝ ⎠
F
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
V
>
--- - Pickup
(EQ 5.45)
F
V
>
--- - Pickup
(EQ 5.46)
F
V
>
--- - Pickup
(EQ 5.47)
F
T60 Transformer Protection System
5.6 GROUPED ELEMENTS
seconds. The V/Hz element
VOLTS/HZ T-RESET
Multiples of volts per hertz pickup
Multiples of volts per hertz pickup
Multiples of volts per hertz pickup
Time
delay
setting
830738A1.CDR
5
Time
delay
setting
830739A1.CDR
Time
delay
setting
830740A1.CDR
5-201