6–112 339 MOTOR PROTECTION SYSTEM – INSTRUCTION MANUAL
S3 PROTECTION CHAPTER 6: SETPOINTS
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 X
For details see Common setpoints
.
BLOCK 1/2/3
For details see Common setpoints
.
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