GE L60 Instruction Manual page 195

CHAPTER 5: SETTINGS
The language can be selected also for the front panel in EnerVista under Maintenance > Change Front Panel.
— Flash messages are status, warning, error, and information messages displayed in response to
FLASH MESSAGE TIME
certain key presses during settings programming. These messages override any normal messages. Use this setting to
change the duration of flash messages on the display.
— If the keypad is inactive for a period of time, the relay automatically reverts to a default
DEFAULT MESSAGE TIMEOUT
message. The inactivity time is modified using this setting to ensure that messages remain on the screen long enough
during programming or reading of actual values.
— To extend phosphor life in the vacuum fluorescent display, the brightness can be
DEFAULT MESSAGE INTENSITY
attenuated during default message display. During keypad interrogation, the display always operates at full brightness.
and
SCREEN SAVER FEATURE SCREEN SAVER WAIT TIME
(LCD) and control its backlighting. When the
followed by the
DEFAULT MESSAGE TIMEOUT
target messages are active. When a keypress occurs or a target becomes active, the LCD backlighting turns on.
— This setting modifies the current cut-off threshold. Very low currents (1 to 2% of the rated value)
CURRENT CUT-OFF LEVEL
are very susceptible to noise. Some customers prefer very low currents to display as zero, while others prefer the current to
display even when the value reflects noise rather than the actual signal. The L60 applies a cut-off value to the magnitudes
and angles of the measured currents. If the magnitude is below the cut-off level, it is substituted with zero. This applies to
phase and ground current phasors as well as true RMS values and symmetrical components. The cut-off operation applies
to quantities used for metering, protection, and control, as well as those used by communications protocols. Note that the
cut-off level for the sensitive ground input is 10 times lower that the
samples available via oscillography are not subject to cut-off.
— This setting modifies the voltage cut-off threshold. Very low secondary voltage measurements
VOLTAGE CUT-OFF LEVEL
(at the fractional volt level) can be affected by noise. Some customers prefer these low voltages to be displayed as zero,
while others prefer the voltage to be displayed even when the value reflects noise rather than the actual signal. The L60
applies a cut-off value to the magnitudes and angles of the measured voltages. If the magnitude is below the cut-off level,
it is substituted with zero. This operation applies to phase and auxiliary voltages, and symmetrical components. The cut-off
operation applies to quantities used for metering, protection, and control, as well as those used by communications
protocols. Raw samples of the voltages available via oscillography are not subject to cut-off.
The and the
CURRENT CUT-OFF LEVEL
power cut-off level is calculated using the following equations. For Delta connections:
For Wye connections:
where VT primary = VT secondary × VT ratio and CT primary = CT secondary × CT ratio.
For example, given the following settings:
: "0.02 pu"
CURRENT CUT-OFF LEVEL
: "1.0 V"
VOLTAGE CUT-OFF LEVEL
: "100 A"
PHASE CT PRIMARY
: "66.4 V"
PHASE VT SECONDARY
: "208.00 : 1"
PHASE VT RATIO
: "Delta"
PHASE VT CONNECTION
We have:
CT primary = "100 A", and
VT primary =
PHASE VT SECONDARY
L60 LINE PHASE COMPARISON SYSTEM – INSTRUCTION MANUAL
— These settings are only visible if the L60 has a liquid crystal display
SCREEN SAVER FEATURE
SCREEN SAVER WAIT TIME
are used to determine the metered power cut-off levels. The
VOLTAGE CUT-OFF LEVEL
x = 66.4 V x 208 = 13811.2 V
PHASE VT RATIO
is "Enabled," the LCD backlighting turns off after the
, provided that no keys have been pressed and no
setting value. Raw current
CURRENT CUT-OFF LEVEL
PRODUCT SETUP
5
Eq. 5-3
Eq. 5-4
Eq. 5-5
5-27