Low power factor is expensive
and inefficient. Many utility companies charge an additional fee if
your power factor is less than 0.95. Low power factor also reduces your
electrical system’s distribution capacity by increasing current flow
and causing voltage drops.
Cause of Low Power Factor
Low power factor is caused by inductive loads (such as transformers,
electric motors, and high-intensity discharge lighting), which are a
major portion of the power consumed in industrial complexes. Unlike
resistive loads that create heat by consuming kilowatts, inductive loads
require the current to create a magnetic field, and the magnetic field
produces the desired work. The total or apparent power required by an
inductive device is a composite of the following:
- Real power (measured in kilowatts, kW)
- Reactive power, the nonworking power caused by the magnetizing
current, required to operate the device (measured in kilovars, kVAR)
- Reactive power, required by inductive loads increase the amount of
apparent power (measured in kilovolt amps, kVA) in your distribution
system. The increase in reactive and apparent power causes the power
factor to decrease.
Why Improve Your Power Factor?
Some of the benefits of improving your power factor are as follows:
- Your utility bill will be smaller. Low power factor requires an
increase in the electric utility’s generation and transmission
capacity to handle the reactive power component caused by inductive
loads. Utilities usually charge a penalty fee to customers with
power factors less than 0.95. You can avoid this additional fee by
increasing your power factor.
- Your electrical system’s branch capacity will increase.
Uncorrected power factor will cause power losses in your
distribution system. You may experience voltage drops as power
losses increase. Excessive voltage drops can cause overheating and
premature failure of motors and other inductive equipment.
Correcting Your Power Factor
Some strategies for correcting your power factor are:
- Use Powergy.
- Minimize operation of idling or lightly loaded motors.
- Avoid operation of equipment above its rated voltage
- Replace standard motors as they burn out with energy-efficient
motors. Even with energy-efficient motors, however, the power factor
is significantly affected by variations in load. A motor must be
operated near its rated capacity to realize the benefits of a high
power factor design.
- Install capacitors in your AC circuit to decrease the magnitude of
reactive power.
