POWER FACTOR CORRECTION
Importance of power factor and power factor correction
Power factor is on the list of design concerns for designers of virtually every device that draws significant power from a mains socket, as well as for engineers in heavy-electrical sectors. Not only are there principles of good engineering practice at stake, there is also legislation to enforce conformance with power-factor norms. Improve the efficiency of your power systems, reduce power bills and avoid power factor penalties from electricity suppliers.
What is a power factor?
Put simply, the power factor describes how efficiently power is being used. It’s expressed as a ratio of the usable (productive) power to the total power supplied by the electricity company. So a power factor of 1 or 100% is the most efficient, 0.90 is 90% efficient and so on.
Things like electric motors, for example, store some of the supplied energy in magnetic fields. Although this energy doesn’t get used productively by the motor, it’s still adding to the current running through your system and the power company still has to recover the costs of providing it. Many power companies also charge an ‘inefficiency penalty’ based on a customer’s power factor.
In addition, the out of sync back and forth flow of this unproductive energy can interfere with the quality of the system’s AC electrical supply.
Correcting a poor power factor
Power factor correction equipment maximizes the efficiency of an electrical system. As a simplified example, large capacitors can be used to store and release energy exactly out of time with the storing and releasing of energy in the magnetic fields of AC motors. This allows the unproductive energy to flow back and forth between the capacitors and the motor, rather than main electricity supply. The overall result is a much more efficient system.
Benefits of power factor correction
- Reduced power factor tariffs and penalties on your electricity bill
- Increased available load/equipment capacity
- Improved system efficiency
- Improved quality of electrical supply
- Reduced greenhouse emissions
- Extended working life of plant machinery