18
l
ort
n
o
C
4.7 Optimal Control Operation
■
In the optimal control
,
connection and
disconnection is selectively performed
for one capacitor circuit with the most
appropriate capacity that will keep the
lagging reactive power within the
target power factor.
■
In the connection
,
capacitors are cut
o f f s e q u e n t i a l l y i n o r d e r t o
decrease capacity until the power
factor becomes the closest to the
target power factor and the lag is
minimized at the same time.
■
Capacitors are cut off sequentially in
order to decrease capacity until the
power factor becomes the closest to
the target power factor but it is never
below the target power factor.
■
The optimal control is suitable for
controlling the different - capacity
capacitor groups in the circuit where load
fluctuation is frequent. But since the
switching of vacuum electromagnetic
contactors become frequent and not
equal
,
the maintenance and inspections
must be performed frequently and each
contactor must be replaced at the end of
their respective lifetime.
■
At the time of turning on the power
supply
,
the device first operates in the
cyclic control mode until all capacitors
C
1
to C
6
(It is C
1
to C
12
at the time of
12
circuits.) are closed. The device then
begins the optimal control operations.
s
i
p
u
-
t
e
s
d
l
o
H
/
o
t
u
A
y
ti
c
a
p
a
C
n
e
h
W
■
on Hold set-up and each capacity is
the same
,
it becomes cyclic operation.
■
The optimal control is not possible
F
F
O
/
N
O
n
o
i
t
a
n
i
b
m
o
C
e
h
t
n
e
h
w
s
e
v
r
e
s
d
o
h
t
e
m
l
o
r
t
n
o
C
.
N
O
s
i
p
u
-
t
e
s
as only cyclic control.
Optimal Control Opration
Lagging
Reactive Power
Time
Total Connection
Capacity
Status of
connection/disconnection
90
240
990
410
110
790
210
1190
4. Explanation of Control and Movement
Summary of Contents for VAR-12A
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