S&C Instruction Sheet 1041-540 21
Switch Control Operation
The 5800 Series switch control can carry out several automatic operations: sectionalizing,
phase imbalance protection, phase imbalance protection with automatic reclose, and
one- or two-shot-lockout of a faulted circuit. These are explained below.
Note:
For any of the automatic operation features to work correctly, the user must
enter an appropriate value for the
Loss of Voltage Threshold
setpoint. See the
SETUP:
Site- Related
screen explanation in Instruction Sheet 1041-530 for more details.
Automatic Operations
The switch control can sectionalize a distribution circuit based on detected fault current
and voltage fluctuations associated with source-side recloser operation.
Note:
In the 5802/5803 controls, the control monitors each feeder (or branch) indepen-
dently and responds to changes on that feeder regardless of the condition of the other
pad-mounted switch and feeder.
When
Sectionalizing
mode is enabled, the switch control uses the following logic to
determine when to trip open the switch:
(a) The switch control continuously monitors all sensed voltage phases and
compares the voltage to the
Loss of Voltage Threshold
setpoint value.
(b)
If the voltage drops below the setpoint on all sensed phases
: The switch control
starts the
Sectionalizer Reset and Extended Voltage Loss Time
timer. In
addition, the control sets an internal counter of recloser operations to “1.”
If a phase or ground overcurrent fault was present within 0.6 seconds prior
to the detected loss of voltage:
The control assumes the voltage loss was caused by
a source-side breaker or recloser opening in response to a load-side overcurrent
fault.
If an overcurrent fault was not detected prior to the loss of voltage
: The control
assumes the voltage loss was caused by a source-side breaker or recloser opening
in response to a source-side overcurrent fault.
(c) The switch control continues to monitor the voltage levels. The control adds one
count to the counter for each time the source-side device opens.
(d) If the “Successful Reclose Reset Time” is greater than zero, then the
Reset on
Successful Reclose
logic is also active. If voltage returns on all sensed phases
(above the loss of voltage threshold) and current is below the fault-detection
threshold, and this condition persists without interruption for longer than the
Successful Reclose Reset Time
setting, the sectionalizing counts and memory
timer are reset and sectionalizing is canceled.
Line Sectionalizing
The second log contains the magnitude and duration information for each “fault.” The
recorded magnitude is the maximum RMS current amplitude encountered during the
“fault.” The duration is recorded in units of milliseconds, with 6.25-millisecond resolution
and a maximum recordable fault duration of 409 seconds (6 minutes, 49 seconds). The
information in this log is displayed on the IntelliLink software
OVERCURRENT FAULT:
Fault Magnitudes
screen and the LCD.
Note:
Because of the delayed rise and fall times of the hardware, the logged time
for detection of ground overcurrent faults may be delayed relative to the logged time
for phase overcurrent faults caused by the same event. In addition, the accuracy of
recorded duration times for ground overcurrent events is affected by the 50-millisec-
ond sampling interval and hardware rise and fall times. Peak magnitude data of ground
overcurrent is also affected by the amount of time that the event is present. Accurate
magnitude recording requires the condition to be present for approximately 400 mil-
liseconds. See S&C Instruction Sheet 1041-530 for additional details.
