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24. TROUBLESHOOTING
1)
Calculation
of
equivalent capacrty P O of harmonic generating equipment
The 'equivalent capacity^
is the
capauty
of a
&pulse
converter converted from the
capacrty
of a
oonsumer's harmonic generating equipment
and
is calculated
with
the following equation. If the
sum of
equivalent capacities is higher than the limit In Table
3,
harmonics must
be
calculated with the fdlowing
proc&&re:
PO
=
Z
(Ki
x
Pi)
[kVA]
Rated capacity: Determined by
the capaclly of
Ki: Canversion factor (refer to Table
2)
the applied motor and found in Table
5.
It
Pi: Rated capacrty
of
harmonic generating equip
should
be
noted that the rated
capacrty
used
here
is
used to calculate generated hamnic
i: Number
of
indicating the conv9rsion circuit type amount and is ditferent from the power
w l y
capacity required for actual inverter drive.
m e n t '
FVA]
-I
2)
Calculation
of
outgoing
harmonic current
Outgoing harmonic current=fundamental wave current (value converted from received power voila@)
x
operation ratio
x
harmonic content
*
Harmonic content: Found in Tabie
4.
Operation ratio: Operation ratio = actual load factor
x
operation time ratio during
30
minutes
Tabie 5
Rated Capacities
and Outgoing Harmonic Currents for Inverter Drive
1
I
3)
Harmonic suppression technique requirement
if
the outgoing harmonic current
is
higher than the maximum value per
1 kW
contract power
x
contract
power, a harmonic suppression technique is required.
4)
Harmonic suppression techniques
I
its DC Jde
or
both
to w p r e s s h a m k
aments
I
Designed
to
switch the converter circuit
m-off
to convert an
inprt
current
I 1
(FR-HC)
High power
factor converter waveform into
a
sine wave,
the
high power factor converter
(FR-HC)
suppresses h a m ~ c current
considerably
The
FR-HC
IS
used
mth
tlw
stardad accessories
I
-
I
Instdation
of m e r
factor
I
When
l a d
with
a
senes
reactor.
the
wwer factor imDrowng cacackor
has
I
'
an effect
of
absorbing
harmonu:
currenk.
impro~ing
capacitor
.
-
.
Transformer ~ I t i P h a S e
Operation
Use
hvo
transformers
with
a phase angle difference
of
30
as in
Y-A, A-A
dearee
harmonlc currenh
combination
lo
provide an
effect
corresponding to
12
pulses, reducing
low-
5
A C
filter
A
capacitor and a reactor are used together to reduce impedance at specrRc
frequencies. prcduang a great effect
of
absortlng h a r m c CUnBnk.
I
This
filler
deteck
the
current
of
a circcuit generating a harmonic current and
6
Active Mer
generates a hamxxic Current
equivalent to
a difference between that ament
and a tundamental wave current to suppress a harmonic Current at a
detectiw
point, providing
a
great
effect of
absorbing harmonic cunenk.
- 1 1 5 -
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