Power Factor Correction

Power factor is a measure of how efficiently certain equipment makes use of the electricity network.

Some types of equipment, referred to as “inductive loads”, such as electric motors and fluorescent lights, draw more current from the electricity network than they need to perform the useful work they are designed to do. These additional currents are out of phase with the supply voltage and perform no useful work, but are required to maintain the magnetic fields within the devices. This means you end up paying for more power than you actually need.

The concept is expressed as the ratio of power consumed (kW) to current flow required (kVA). A power factor of 1.0 is perfect. A power factor of 0.8 means the useful work being done is 80% of what could be done with the same power and a perfect power factor.

Your energy retailer should be able to tell you what your power factor is - it's worth giving them a call.

Power factor correction equipment can be used to bring low power factor installations closer to a power factor of 1.0.

Power factor correction involves using capacitors that have opposite characteristics to inductive loads, and cancel out the inductive currents. By sensing inductive loads and automatically substituting an equal but opposite amount of capacitive load, power factor correction equipment improves the power factor of a site to typically within 1-2% of the optimum. Power factor correction equipment is installed in the switchboard, and does not affect the operation of other equipment within a building.

The most common technical obstacle to implementing power factor correction is simply a lack of available space in the building switchboard and/or switchroom to install power factor correction equipment.