Power Factor Correction
Power quality is critical to efficient operation of equipment. One contributing element to power quality is power factor. Commercial Energy Solutions help businesses be more productive with their energy using Power Factor Correction.
What is Power Factor?
Simply, it is a measure of how efficiently the load current is being converted into useful work output and is a good indicator of the effect of the load current on the efficiency of the supply system. A poor Power Factor occurs when a load is drawing more electrical energy than is necessary, for conversion into a given amount of useful work.
Power factor is the measure of how effective incoming power is being used at a site; it is expressed as a numerical value between 0 and 1. The closer a power factor is to one, the more efficiently a business is consuming electricity. A power factor between 0.95 and 1 is more cost effective.
Worried you are drawing more power than what is actually required to operate your business? Contact us now on (08) 8234 5101 or complete our online contact form to arrange a FREE No-Obligation Level 1 Energy Audit.
How Does It Work ?
So consider a barge being pulled by a horse:
Since the horse cannot walk on water its pulling effort is reduced by the “angle” of the tow rope.
If the horse could walk on water then all the horse power is being used to pull the load.
However the relative position of the horse influences the power. As the horse gets closer to the barge, angle Ø1 increases and power is wasted, but, as the horse is positioned further away, then angle Ø2 gets closer to zero and less power is wasted
By improving Power Factor (reducing the angle), the reactive power component is reduced.
Consider This :
When you buy fuel for a vehicle, the manufacturer makes it in litres, the pump dispenses it in litres and you pay for it in litres. $/litre – simple!
When you buy electricity, the electricity supplier makes kVA (kilo volt amperes) and you pay for it in kWh (kilowatt hours) or maybe on your bill (Units) – not so simple!
So what is the kilowatt hour (or unit) we get on our bills? Basically, 1000 watts of electricity being used for 1 hour.
Example: 10 x 100 watt lamps x 1 hour=1000 watts/hr divided by 1000=1kWh – simple!
Now here comes the problem: In an alternating current (AC) electrical supply, a mysterious thing called ‘Power Factor’ comes into play. Power Factor is simply the measure of the efficiency of the power being used, a power factor of 1 would mean 100% of the supply is being used efficiently. A power factor of 0.5 means the use of the power is very inefficient or wasteful.
So what causes Power Factor to change? In the world of industry and commerce, a power factor of 1 is not obtainable because equipment such as electric motors, welding sets, fluorescent and high bay lighting create what is called an ‘inductive load’ which in turn causes the amps in the supply to lag the volts. The resulting lag is called Power Factor.
How this power is wasted can be shown graphically since in 3 phase power supplies ‘power’ can be represented and measured as a triangle. ACTIVE Power is the base line and is the ‘real’ usable power measured and paid for in kW. REACTIVE power is the vertical or that part of the supply which causes the inductive load. The reactive power in is measured in kVAr (kilo volt-amperes reactive). APPARENT Power is the hypotenuse. This is the component the electricity generator must supply and it is the resultant of the other two components, measured in kVA.
In a 3 phase power supply, kW consumed is 3 phase VOLTS x AMPS x 1.73 x Power Factor. The Electricity Company supply you VOLTS x AMPS and they have to supply extra to make up for the loss caused by poor Power Factor.
When the power factor falls below a set figure, the electricity supply companies charge a premium on the kW being consumed, or, charge for the whole supply as kVA by adding reactive power charges (kVar) to the bill.
Power Factor Correction aims to improve power factor, utilising capacitors to offset usually inductive loads, for example motors. Power Factor Correction systems increase the efficiency of power supply, delivering immediate cost savings on electricity.
- Reduced cost: Reduction in kVA demand and therefore reduced electricity costs.
- Equipment life: Extend the life of your equipment.
- Compliance: Compliance with regulatory codes.
- Expansion: More power available for site expansion without the need for new switchboards and cable.