BECKWITH ELECTRIC M-6280A, Instruction Book

Page: 288 / 462

Configuration – 4
4–97
Sequence with all “Prior Operation” actions
enabled
When a capacitor bank performs an Open or Close
operation, and within 1 minute of the Open/Close
operation the detected neutral current exceeds the
Bank/Switch Failed Level 2 setting for the duration
of the Bank/Switch Failed Level 2 Time delay setting,
the control will sequence through the following
actions as long as detected neutral current exceeds
the Bank/Switch Failed Level 2 setting:
1. Retry the operation (up to nine retry
operations)
2. Attempt a reverse operation (1)
3. Block Operation
4. HMI displays "NC Block in effect",
CapTalk Metering and Status screen
Block Status indicates a Neutral Current
Block is in effect
5. Start “Block Reset Time Delay” timer
6. Remove Block control operation when
“Block Reset Time Delay” timer times out
7. HMI and CapTalk Metering and Status
screen no longer indicate a Neutral
Current Block is in effect
8. Resume operation
If at any time the detected neutral current decreases
to less than the Bank/Switch Failed Level 2 setting
the sequence of actions will stop and normal control
operation will resume.
During Retry Operations the control will ignore the
controlling parameter (voltage or current) in relation
to being in band or not, unless the parameter
exceeds the band opposite the operation it is
retrying. If that occurs, the control will stop the retry
function and perform the required operation instead.
During a Retry Operation the control will ignore
the controlling parameter (voltage or current) in
relation to being in band or not unless the parameter
exceeds the band opposite the operation it is
Retrying. If that occurs, the control will halt the
Retry Operation function and perform the required
operation instead. For example, if Retrying a Close
and a voltage based controls measured voltage
rises above the Control Open Voltage setting and
times out, the Control will stop the Retry Close
operation and perform the Open.
During a Reverse Operation, the control will ignore
the controlling parameter (voltage or current) in
relation to being in band or not unless the parameter
exceeds the band opposite the operation it is
retrying. If that occurs, the control will stop the
reverse function and perform the required operation
instead.
During a Reverse Operation, the control will ignore
the controlling parameter (voltage or current) in
relation to being in band or not unless the parameter
exceeds the band limit of the operation it is reversing
to. If that occurs, the control will halt the Reverse
Operation and Block function and perform the
required operation instead. For example, if opening
due to a Reverse condition after a Close operation
and a voltage based controls measured voltage
rises above the Control Open Voltage setting
and times out, the Control will stop reversing and
perform the normal Open operation.
The “Block Reset Time Delay” timer is stored on a
loss of power to the control. When power is restored,
the control will compare the Block start date/time
with the unit’s date/time and apply the remaining
time if any. If the time is exceeded, the block will
be cleared/reset.
Clear Neutral Current Block (Prior Operation)
The Neutral Current Block initiated in the “Prior
Operation” scheme can be cleared/reset by any of
the following methods:
• Remotely from CapTalk. CapTalk provides
a “Neutral Current Block Reset” selection
on the “Alarms” dialog screen Figure 4-40.
• Remotely through a DNP Binary/Control
Output point named "Reset NC Block".
• Locally from the Programmable Alarm
menu in the Configuration menu.
• The capacitor bank switch is manually
operated in the direction that caused the
block and the detected neutral current is
less than the Bank/Switch Failed Level 2
setting.
• The “Lockout Reset Time Delay” is
enabled and the timer expires.