Rockwell Automation 1413-ME-PEA Capacitor Bank Controller - Series B - Manual (Page 40)

Publication 1413-UM001C-EN-P - May 2006
38 Operation
• Linear (mode = 1) – This mode of operation switches the
capacitor steps on and off in first-in, last-out (FILO) order. That
is, the first step on is the last step turned off. This is most useful
when all the capacitor steps are of similar sized.
• Balanced (mode = 2) – This mode counts the number of
opening operations on each capacitor step and switch-capacitor
steps to balance the number of opening operations equally
across all of the employed capacitor steps. This mode is also
most useful when all of the steps are of similar size.
• Best Fit (mode = 3) – This mode selects capacitor steps to be
switched on and off to most closely achieve the target power
factor and kVAR needs of the system. When the system’s kVAR
needs increase, the available step or steps with the closest
(aggregated) kVAR rating is added. On decreasing kVAR
demand, steps are switched off in similar fashion.
• Special (mode = 4) – This mode is reserved for
customer-defined switching sequences not described above
including voltage, current, and time of day type functions.
Special-switching mode might include switching on parameters
such as PF, current, voltage, time of day, weekends / weekdays,
or seasonal adjustments.
Refer to Add Special Functionality on page 51.
• %THD (mode = 5) – This mode selects capacitor steps to be
added in a linear fashion (for example, step 1, step 2) until the
%THD_V is below the setpoint for a user-configurable time
delay (default 60 seconds). The system will start to remove
capacitor steps when the %THD_V is 1% below the setpoint for
the user-configurable delay.
CTPT Modes The CTPT mode configures the capacitor bank controller to be
connected to current transformers (CTs) and potential transformers
(PTs) in one of three ways:
• 0 = Normal mode - CTs and PTs are installed in a typical
three-phase configuration. The controller uses the real- and
reactive-power data produced by the power monitor(s) without
further processing.
• 1 = NEU mode - One CT wired on the A phase and one PT
wired from phase A to neutral are installed on a three-phase
circuit. The power monitors must be set up in Wye-wiring mode.
The controller multiplies the real- and reactive-power data
produced by the power monitors by 3.