WHAT IS POWER FACTOR CORRECTION
POWER FACTOR SYSTEMS
A power factor system is made up of capacitor banks, which are engaged and disengaged with power factor contactors, using a smart controller which measures the load and engages the capacitor banks to correct the power factor level according to the load being drawn at the time.
Excess energy, which is not needed is removed from the network and stored in the capacitor banks. This in turn reduces the maximum demand levels (kVA) and prevents any unnecessary spikes on the supply.
POWER FACTOR LEVEL
The power factor level of a supply can be seen as a percentage of efficiency at which energy is used on an inductive load.
Inductive load is load drawn by motor driven equipment, which includes air-conditioning, refrigeration plants, chiller plants and DC\Alternative speed drives.
The desired power factor level for any supply with inductive load is 0.99.
Correcting power factor levels is mainly beneficial where kVA charges are applicable. By lowering the maximum demand, the kVA is reduced – resulting in lower charges from the local supply authority.
With electricity tariffs constantly on the rise, the rate per kVA constantly changes and depending on the local supply authority, becomes more expensive during winter months.
Return on investment periods can range from 6 – 24 months.
Not only are power factor systems a great way of reducing energy costs, they also reduce carbon emissions, thereby contributing to the urgent need to reduce our carbon footprint.
DETERMINING THE REQUIRED SIZE OF A POWER FACTOR SYSTEM
The best way of determining the required size of a power factor system is to measure and record the existing power factor level of the supply and establishing an average of the maximum demand usage.
It is also important to measure for harmonics in the electrical supply.
Harmonics can be caused by high volumes of DC\Variable and Alternative speed drives, electrical welding, high concentrations of LED lighting, computers and UPS units.
Bad harmonics cause a distortion of the sine waves in an electrical supply, thereby changing the frequency of the supply as well as distorting the phase rotation.
Installing a power factor system onto a supply with existing harmonics can amplify the bad harmonics, as these harmonics resonate within the capacitor banks and are amplified before going back into the network.
In this instance, a power factor system must be installed with harmonic reactors, which do not eliminate the bad harmonics, but do not amplify them in any way.