Case Studies

3 Fluke Corporation Power Quality Case Study: Clean power delivers clean water
Figure 2 and 3: Power usage
The Fluke 434 shows the power usage of the MCC with and without the power conditioner.
N
ote the reductions in reactive power (kVAR), apparent power (kVA) and rms current (Arms).
P
ower factor is ideal with the corrector activated.
Figure 5 and 6: Harmonic correction
The Fluke 434 shows the harmonic distortion with and without the conditioner. The fifth
harmonic is the biggest c
ontributor to the current distortion. With the power conditioner turned
on (right) note the sig
nificant reduction in the fifth harmonic
. Current T
H
D not displayed.
Figure 7 and 8: Harmonics aff
ects on voltage and current
These screens show phase A voltage and current w
ith and w
ithout the power c
orrector
.
Note the effect of phase correction and harmonic cleanup on the current waveform.
Before and after
The power correction system
lived up to expectations. Six
screens from the power quality
analy
zer tell the whole story.
The change in current is a
real testimony to the impact of
power factor correction. By
correcting the power factor the
rms current drawn by the MCC
was reduced by 27 %. You can
see what happens in the power
measurements. The power
conditioner uses a relatively
small amount of power to run.
But it counteracts the reactive
power, and reduces the appar-
ent power (kVA’s) dramatically.
You can see the power relation-
ships in the vector diagrams
below.
Prior to the installation, the
upstream distribution equip-
ment had to carry a lot of
reactive current and harmonic
current that was sloshing
around without doing any real
work. Now the system carries
only hard-working current to
the MCC’s.
The power corrector cleaned
up the harmonic content, too.
Most of the non-linear load
was from large motor drives.
The 5th harmonic was a big
contributor to the overall distor
-
tion. Both the amount of the 5th
harmonic current and the
current THD were cut by more
than 50 %.
Without power corrector With power corrector
Figure 4: Reactive (kVAR) vs. apparent (kVA) power.
100.9 kVA
73.61 kVAR
100.9 kVA
73.4 kVA
10.84 kVAR
72.6 kVA
Bef
ore
After
Before
After
Bef
ore
After