BECKWITH ELECTRIC M-6280A, Инструкция

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M-6280A Instruction Book
4–98
No Prior Operation Element
The “No Prior Operation” element of the Bank/
Switch Failed Level 2 feature considers detected
neutral current after a prescribed time period (No
Prior Operation is considered to be greater than
one minute following switch operation) and in the
event that the detected neutral current exceeds the
Bank/Switch Failed Level 2 setpoint, activates user
selected “No Prior Operation” actions in a specific
sequence.
The “No Prior Operation” element includes the
following user selectable actions:
• Open and Lockout Time Delay (1 to 4320
minutes)
• Lockout Reset Time Delay (1 to 72 hours)
Sequence with all “No Prior Operation”
actions enabled
When a capacitor bank performs a Close operation
and greater than 1 minute after the Close operation
the detected neutral current exceeds the Bank/
Switch Failed Level 2 setting for the duration of the
Prior Operation Time delay setting, the control will
sequence through the following actions as long
as detected neutral current exceeds Bank/Switch
Failed Level 2 setting:
1. Start “Open and Lockout Reset Time
Delay” timer
2. When “Open and Lockout Reset Delay
Timer” times out, capacitor bank Open is
initiated and control operation is locked
out
3. HMI displays "NC Lockout in effect",
CapTalk Metering and Status screen
Block Status indicates a Neutral Current
Lockout is in effect
4. Start “Lockout Reset Time Delay” timer
5. Remove control operation lockout when
“Lockout Reset Time Delay” times out
6. HMI and CapTalk Metering and Status
screen no longer indicate a Neutral
Current Lockout is in effect
7. 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.
Clear Neutral Current Lockout (No Prior
Operation)
The Neutral Current Lockout initiated in the “No Prior
Operation” scheme can be cleared/reset by any of
the following methods:
• Remotely from CapTalk . CapTalk provides
a “Neutral Current Lockout Reset”
selection on the “Alarms” dialog screen
Figure 4-40.
• Remotely through a DNP Binary/Control
Output point named "Reset NC Lockout".
• Locally from the Programmable Alarm
menu in the Configuration menu.
• The capacitor bank switch is Closed
manually 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.
The Lockout Reset Time Delay” timer is stored
on power loss and upon power restoration it will
compare the Lockout start date/time with the unit’s
date/time and apply the remaining time if any. If the
time is exceeded, the lockout would be cleared/
reset.
If the control is placed in Manual from the front
panel Auto/Manual switch and a neutral overcurrent
alarm is received, the control will not take action
to operate the bank to retry, reverse, or lockout. It
will alarm only.