S&C Instruction Sheet 1041-540 23
Switch Control Operation
STEP 2.
At the
SETUP: Automatic Operation
screen, enter values for the
Phase Loss
Protection Time Threshold
and the
Phase Loss Protection Current
Threshold
timers. A
Phase Loss Protection Voltage Threshold
value can
also be entered. Otherwise, the switch control uses the
Loss of Voltage
Threshold
value on the
SETUP: Site-Related
screen. See the
SETUP:
Automatic Operation
screen explanation in Instruction Sheet 1041-530 for
details.
NOTICE
Be sure to select a conservative value for the
Phase Loss Protection
Current Threshold setting, one that is clearly below the load break rating
for the line switch .
Use either the faceplate automatic operation ENABLE/DISABLE switch or
a SCADA command to enable automatic operation of the switch control.
When the
Automatic Reclose
feature is enabled and the switch is tripped open because
of a phase imbalance, the switch control recloses the switch once voltage is again present
on all three phases. (If
Phase Loss Protection
feature is enabled but
Automatic
Reclose
feature is not, an operator must use the faceplate switch or a SCADA command
to manually close the tripped switch.)
Note:
Automatic reclose is not available in conjunction with automatic transfer.
When Automatic reclose is enabled, the switch control uses the following logic to
determine when to reclose the switch:
(a) The switch control monitors the line for the return of all voltage phases.
(b) As soon as the switch control senses voltage is present on all three phases, it
starts the “Automatic Reclose” timer.
(c) If voltage remains continuously present for the duration of the timer, the switch
control recloses the tripped switch.
Note:
Automatic Reclose only occurs if the switch control tripped the switch open
because of phase imbalance; switches opened for other reasons must be reclosed
manually.
Complete the following steps to enable the
Automatic Reclose
feature:
STEP 1.
In the
Features Enabled
field on the
SETUP: Automatic Operation
screen,
select a combination that includes “Phase Loss Protection with Automatic
Reclose.”
STEP 2.
At the
SETUP: Automatic Operation
screen, enter values for the
Phase Loss
Protection Time Threshold
, the
Phase Loss Protection Current
Threshold
, and the
Phase Loss Protection Automatic Reclose Time
Threshold
settings. A
Phase Loss Protection Voltage Threshold
value can
also be entered. Otherwise, the switch control uses the
Loss of Voltage
Threshold
setting on the
SETUP: Site-Related
screen. See the
SETUP:
Automatic Operation
screen explanation in S&C Instruction Sheet 1041-530
for details.
STEP 3.
Use either the faceplate automatic operation ENABLE/DISABLE switch or a
SCADA command to enable automatic operation of the switch control.
Phase Loss Protection
with Automatic
Reclose
