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350 FEEDER PROTECTION SYSTEM – INSTRUCTION MANUAL
S3 PROTECTION
CHAPTER 6: SETPOINTS
NTRL DIR FUNCTION
Range: Disabled, Latched Alarm, Alarm, Control
Default: Disabled
When an
Alarm
function is selected, the alarm LED will flash upon detection of Reverse
direction, and will drop out when the direction changes to Forward. When
Latched
Alarm
is selected, the alarm LED will flash upon detection of Reverse direction, and will
stay lit (latched) after the direction changes to Forward. The alarm LED can be reset, by
issuing a Reset command. Detection of Reverse direction when the
Control
function is
selected, does not trigger the alarm LED.
NTRL DIR POLARIZING
Range: Voltage, Current, Dual
Default: Voltage
This setting specifies the voltage polarizing signal for the detection of Forward and
Reverse directions.
NTRL DIR MTA
Range: 0° to 359° Lead in steps of 1°
Default: 315°
This setting sets the Maximum Torque Angle (MTA), for the Neutral Directional element to
define the regions of Forward and Reverse directions. For Voltage polarizing, enter the
maximum torque angle by which the operating current leads the polarizing voltage. This
is the angle of maximum sensitivity.
MIN POL VOLTAGE
Range: 0.05 to 1.25 x VT in steps of 0.01
Default: 0.05 x VT
This setting affects only cases where voltage or dual polarizing is selected. The minimum
zero sequence voltage level must be selected to prevent operation due to normal
system unbalances, or voltage transformer errors. Set the minimum zero sequence
voltage level to 2% of VT for well balanced systems, and 1% of VT accuracy. For systems
with high resistance grounding or floating neutrals, this setting can be as high as 20%.
The default of 5% of VT is appropriate for most solidly grounded systems.
OUTPUT RELAY 3 to 6
Range: Do not operate, Operate
Default: Do not operate
Any or all of the output relays 3 to 6 can be selected to operate upon Neutral Directional
operation. The selection of relay outputs operation is available no matter whether
Latched Alarm, Alarm, or Trip function is selected.
BLOCK 1/2/3
Range: Off, Contact Input 1 to 10[8], Virtual Input 1 to 32, Remote Input 1 to 32, Logic
Element 1 to 16
Default: Off
Three blocking inputs are provided in the Neutral Directional menu. One blocking input
going “high” is enough to block the function. The selection for each block can be Contact
input, Virtual Input, Remote Input, or Logic Element.
