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Directional Sensitive Ground/Earth
(SGF/SEF) Fault
The Directional SGF/SEF Fault feature adds directional
capabilities to the SGF/SEF protection features. It pro-
vides a sensitive ground/earth trip if the fault is downline
of the recloser on a radial distribution system. Directional
SGF/SEF is used on ungrounded Delta systems for sup-
pression of ground trips for faults occurring on other circuit
branches.
The user sets the parameters for Direction SGF/SEF
through the interface software via the Protection Profile
menu. See Figure 15. In addition to the normal (non-direc-
tional) SGF/SEF settings, the user enters the following
directional SGF/SEF parameters:
• Direction Enable
Note:
If Direction Enable is not selected, SGF/SEF tripping
occurs through normal (non-directional) settings.
• Maximum Torque Angle (-180° to 180°, in 1° increments)
• Torque Angle Width (10° to 90°, in 1° increments)
• Zero Sequence Voltage (V
0
)
Threshold (4 to 130 V)
The Maximum Torque Angle parameter determines the
angle of maximum tripping sensitivity between the phase
angle of the zero sequence voltage and current at the time
of fault. The setting of this value depends on knowledge
of the power system. Typically, a resistive fault has a
value of 0°, and a capacitive fault has a value of 90°.
Torque Angle Width parameter restricts the tripping to an
angle of plus or minus the specified width about the
Torque angle setting. For example, if the Maximum
Torque Angle is 45°, and the Torque Angle Width is set for
10°, then the control will trip at angles between 35° and
55°.
The Zero Sequence Voltage Threshold is used to set the
threshold voltage below the disabled directional SGF/SEF
tripping voltage.
Note: In most cases, a default value of 4 is adequate.
Directional SGF/SEF Fault is recorded as an event in the
control Event Recorder for retrieval. Refer to Service Infor-
mation S280-79-2 Form 5 Microprocessor-Based Recloser
Control Programming Guide for additional information.
Kyle Form 5, Form 5 UDP, Form 5 DC NOVA Recloser Control Installation and Operation Instructions
18
Figure 15.
Directional SGF/SEF configuration screen.