A high-power factor
eliminates penalty amount imposed when operating with a low power factor. For
many years, most utilities demanded a minimum of 85% power factor as an average
for each monthly billing. Now many of these same utilities are demanding 95%…or
else pay a penalty! The actual wording or formula in the utility rate contract
might spell out the required power factor, or it might refer to KVA billing, or
it might refer to KW demand billing with power factor adjustment multipliers.
Have your utility representative explain the particular rate contract used in
your monthly bill. This will insure you are taking the proper steps to obtain
maximum savings by maintaining a proper power factor.
Additional
Capacity in Electrical System
A high-power factor can help
you utilize the full capacity of your electrical system. To refresh our memory,
let’s look again at the power triangle story, shown on figures 1, 2. Remember
that KVA is a measure of the total power generated by the utility for you to
accomplish your KW of work.
Remember that the KVA figure
is the amount of power passing through your plant transformer, and limited by
its rated size: e.g. 750 KVA, 1500 KVA, 2500 KVA, etc. In the previous example,
we reduced your transformer loading from 1160 to 913 KVA, thus allowing for
more load to be added in the future.
Reduction
of I^2 R Losses
A potential savings in
billed KW-Hrs can be realized depending upon where the capacitors are located
in your electrical system. When capacitors are energized they reduce the total
power usage (KVA) from their location in the system up to the utility source.
In other words, capacitors reduce the current in amperes that had been flowing
from the utility to the capacitor location. This ampere reduction might be as
high as 20%. Since watt loss generated by current passing through a conductor
is expressed by the formula…
Ø Watt
loss = (Ampere) 2 x Conductor Resistance (W=I2R)
It is obvious that locating
the capacitors at the extremities of the feeders and branch circuits (where the
loads are) can result in a sizeable reduction in total KW-Hrs usage every
month.
Source: Power factor
correction application guide
