GE T60 Instruction Manual page 470

GROUPED ELEMENTS
The undervoltage elements can be programmed to have a definite time delay characteristic. The definite time curve
operates when the voltage drops below the pickup level for a specified period of time. The time delay is adjustable from 0
to 600.00 seconds in steps of 0.01. The undervoltage elements can also be programmed to have an inverse time delay
characteristic.
The undervoltage delay setting defines the family of curves shown as follows.
where
T = operating time
D = undervoltage delay setting (D = 0.00 operates instantaneously)
V = secondary voltage applied to the relay
V = pickup level
pickup
5
At 0% of pickup, the operating time equals the
5.7.12.2 Phase undervoltage (ANSI 27P, IEC PTUV)
SETTINGS  GROUPED ELEMENTS  SETTING GROUP 1(6)  VOLTAGE ELEMENTS  PHASE UNDERVOLTAGE1(3)
 PHASE
 UNDERVOLTAGE1
5-288
Figure 5-163: Inverse time undervoltage curves
PHASE UNDERVOLTAGE DELAY
PHASE UV1

FUNCTION: Disabled
PHASE UV1 SIGNAL

SOURCE: SRC 1
PHASE UV1 MODE:

Phase to Ground
PHASE UV1

PICKUP: 1.000 pu
PHASE UV1

CURVE: Definite Time
PHASE UV1

DELAY: 1.00 s
setting.
Range: Disabled, Enabled
Range: SRC 1, SRC 2, SRC 3, SRC 4, SRC 5, SRC 6
Range: Phase to Ground, Phase to Phase
Range: 0.004 to 3.000 pu in steps of 0.001
Range: Definite Time, Inverse Time
Range: 0.00 to 600.00 s in steps of 0.01
T60 TRANSFORMER PROTECTION SYSTEM – INSTRUCTION MANUAL
CHAPTER 5: SETTINGS
Eq. 5-51