TAS APFC-06 04 User Manual page 10

Power Factor Controller APFC 06
Case-3: PF
UPPER
-
kW
PF
LOWER.
PF
UPPER.
There are two PF set points to be set in APFC 06. The UPPER limit and
the LOWER limit. APFC 06 ensures that PF-UPPER is never exceeded.
Additionally, "No change band" to minimum kVAr band size equal to
smallest bank kVAr x 1.5 ensures no hunting during the low kW loading.
APFC 06 is normally set for PF settings as per first two diagrams shown
where PF LOWER is inductive. This philosophy helps to optimize the
system maximum kVAr to be used as well as reduces the number of
switching operations during higher loading conditions. This ensures better
life expectancies of the switched capacitors as well as the switching
devices.
This methodology of kVAr compensation reduces the complex settings
that are used by conventional PF relays. The settings like C/K ratio and
kVAr offsets/shifts are eliminated which makes APFC 06 user friendly and
thus easy to commission.
& PF- both set as Capacitive:
LOWER
kVAr
(Ind)
No change band.
Capacitor addition band.
Capacitor removal band.
- 8 -
smallest
Capacitor bank
kVAr x 1.5 width.
kVAr
(Cap)
kW.
PF
LOWER.
PF
UPPER.