GE UR F35 Series Instruction Manual page 144

5.2 PRODUCT SETUP
• DEFAULT MESSAGE INTENSITY: To extend phosphor life in the vacuum fluorescent display, the brightness can be
attenuated during default message display. During keypad interrogation, the display always operates at full brightness.
• SCREEN SAVER FEATURE and SCREEN SAVER WAIT TIME: These settings are only visible if the F35 has a liquid
crystal display (LCD) and control its backlighting. When the
is turned off after the
have been pressed and no target messages are active. When a keypress occurs or a target becomes active, the LCD
backlighting is turned on.
• CURRENT CUT-OFF LEVEL: This setting modifies the current cut-off threshold. Very low currents (1 to 2% of the
rated value) are very susceptible to noise. Some customers prefer very low currents to display as zero, while others
prefer the current be displayed even when the value reflects noise rather than the actual signal. The F35 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 substi-
tuted with zero. This applies to phase and ground current phasors as well as true RMS values and symmetrical compo-
nents. 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
setting value. Raw current samples available via oscillography are not subject to cut-off.
CUT-OFF LEVEL
• VOLTAGE CUT-OFF LEVEL: This setting modifies the voltage cut-off threshold. Very low secondary voltage measure-
ments (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 sig-
nal. The F35 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 cut-off.
The
CURRENT CUT-OFF LEVEL
power cut-off level is calculated as shown below. For Delta connections:
5
3-phase power cut-off
For Wye connections:
3-phase power cut-off
per-phase power cut-off
where VT primary = VT secondary × VT ratio and CT primary = CT secondary × CT ratio.
For example, given the following settings:
CURRENT CUT-OFF LEVEL
VOLTAGE CUT-OFF LEVEL
PHASE CT PRIMARY
PHASE VT SECONDARY
: "208.00 : 1"
PHASE VT RATIO
PHASE VT CONNECTION
We have:
CT primary = "100 A", and
VT primary =
PHASE VT SECONDARY
The power cut-off is therefore:
power cut-off = (
CURRENT CUT-OFF LEVEL
= (
= 720.5 watts
Any calculated power value below this cut-off will not be displayed. As well, the three-phase energy data will not accumu-
late if the total power from all three phases does not exceed the power cut-off.
5-20
DEFAULT MESSAGE TIMEOUT
and the
VOLTAGE CUT-OFF LEVEL
×
3
CURRENT CUT-OFF LEVEL
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- -
=
3 ×
CURRENT CUT-OFF LEVEL
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- -
=
CURRENT CUT-OFF LEVEL
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- -
=
: "0.02 pu"
: "1.0 V"
: "100 A"
: "66.4 V"
: "Delta".
x
PHASE VT RATIO
×
VOLTAGE CUT-OFF LEVEL
× 0.02 pu × 1.0 V × 100 A × 13811.2 V) / 66.4 V
3
F35 Multiple Feeder Protection System
SCREEN SAVER FEATURE
followed by the
SCREEN SAVER WAIT TIME
are used to determine the metered power cut-off levels. The
×
VOLTAGE CUT-OFF LEVEL
VT secondary
× ×
VOLTAGE CUT-OFF LEVEL
VT secondary
× ×
VOLTAGE CUT-OFF LEVEL
VT secondary
= 66.4 V x 208 = 13811.2 V
× CT primary × VT primary)/VT secondary
5 SETTINGS
is "Enabled", the LCD backlighting
, providing that no keys
CURRENT
× ×
VT primary CT primary
VT primary × CT primary
VT primary × CT primary
GE Multilin
(EQ 5.3)
(EQ 5.4)
(EQ 5.5)