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In a
typical industrial plant, AC induction motors constitute a large portion of the
equipment. Since induction motors are mainly inductive loads, they are likely
to lead to a low power factor. Some of the benefits of improving your power
factor include:
Lower
Utility Fees
Inductive
loads, which require reactive power, are the main cause of a low power factor.
This increase in required reactive power (KVAR) causes an increase in required
apparent power (KVA), which is what the utility company supplies to your facility
So,
a facility’s low power factor causes the electricity company to have to increase
its generation and transmission capacity in order to handle this extra demand. By
lowering your power factor, you use less KVAR. This results in less KW, which equates
to a dollar savings from the utility company. Also note that a utility company
will charge any consumer whose power factor is less than 0.95 an additional
fee. If you reduce power factor you can avoid this additional fee.
Increased System Capacity
By
improving power factor, the KW capacity of the system is increased. This
implies that for a given KVA, as we improve power factor, the reactive power
component, KWAR, decreases and the KW component increases.
Reduced System Losses
As
current flows through conductors, the conductors produce heat. This heating is
power loss. Power loss is proportional to current squared (PLoss =I2
R) and current is proportional to the power factor. In any given electrical
distribution system, Conductor loss can account for as much as 2-5% of total
load.
By
improving your power factor, these losses can be reduced. With the current rise
in the cost of energy due to ever increasing fluctuations in the price of crude
oil, increased facility efficiency is very desirable. And with lower system
losses, you are also able to add additional load to your system.
Increased Voltage Level and
Cooler and More Efficient Motors
Uncorrected
power factor causes power system losses in the distribution system. As power
losses increase, voltage drops. Excessive voltage drops can cause overheating
and premature failure of motors and other inductive equipment.
By
improving the power factor of your plant, you will minimize these voltage
drops
along feeder cables and avoid related problems. Your motors will run cooler and
be more efficient, with a slight increase in capacity and starting torque. Also
note that Severe over-correction (P.F. greater than 1) will cause a voltage rise that can
damage insulation & equipment; or result in utility surcharges!
