Rockwell Automation 1413-ME-PEA Capacitor Bank Controller - Series B - Manual (Page 39)

37 Publication 1413-UM001C-EN-P - May 2006
Chapter
3
Operation
Introduction The capacitor bank controller gathers real- and reactive-power data
using one or more Powermonitor meters. The processor manipulates
data in engineering units of kVAR and kW. The unit does not directly
control power factor, but rather works to actively minimize imported
and exported kVAR. The net result of this philosophy indirectly
controls power factor and minimizes voltage excursions associated
with excessive kVAR export.
The capacitor bank controller can accommodate up to four different
utility feeds and/or generators. Each feed requires an individual
Powermonitor meter. The unit sums the kW and kVAR readings from
each of the Powermonitor meters to arrive at an aggregate kVAR so
that a single capacitor bank could be used to compensate several
feeds simultaneously.
The traditional C/k ratio is not required for the capacitor bank
controller since we are working in engineering units within the
processor.
Aggregate Power Factor is calculated and displayed using the
following formula:
The Powermonitor meter data is gathered with RS-485 ports using the
DF-1 half-duplex protocol at a data rate of 19.2 Kbps.
Operating Modes Each capacitor step can be individually selected to on, off, or auto
status. The capacitor discharge-timer interlock is in effect in Manual
mode to prevent capacitor bank damage. In Auto mode, a step is
available to any of the automatic sequences described below. In the
On or Off mode, a step is unavailable to any automatic operating
mode.
• Manual (mode = 0) – This mode disables all automatic
operating modes.
Manual mode is the default configuration. All capacitor steps
have a default configuration of auto.
PF
Aggregate
KW
Aggregate
KW
Aggregate
2
KVAR
Aggregate
2
+
------------------------------------------------------------------------------ =