The Reactive Power charge on your electricity bill is directly targeted against those companies who do not demonstrate clear energy efficiency use. You will find this charge itemised on your electricity bill.

Reactive power charges can be made significantly smaller by the introduction of Power Factor Correction Capacitors which are a widely recognised method of reducing an electrical load and minimising wasted energy, improving the efficiency of a plant and reducing the electricity bill.

It is not always necessary to reach a power factor of 1. A cost effective solution can be achieved by increasing your power factor to greater than 0.95

A full site survey is required to determine what type and size of system is required to meet your current and future needs.

Power Factor Correction Ltd will carry out the survey, including harmonic analysis, and the cost of the survey can be remitted against the cost of the equipment purchased.

Once in place, the cost of PFC can often be recovered in less than 1 year.

What is Power Factor?

Power Factor is a measure of how efficiently electrical power is consumed. In the ideal world Power Factor would be unity (or 1). Unfortunately in the real world Power Factor is reduced by highly inductive loads to 0.7 or less. This induction is caused by equipment such as lightly loaded electric motors, luminaire transformers and fluorescent lighting ballasts and welding sets, etc.

What does it do to my electricity bill?

In a 3 phase supply, kW consumed is (VOLTS x AMPS x 1.73 x Power Factor) / 1000. 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.

What causes Power Factor to change?

Inductive loads cause the AMPS to lag behind the VOLTS. The wave forms of VOLTS and AMPS are then "out of phase" with each other. The more out of phase they become then the lower the Power Factor. Power Factor is usually expressed as Cos Phi.

In 3 phase power supplies the "power" can be measured as a triangle.

ACTIVE Power is the base line and is the real usable power measured 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 resultant of the other two components and is measured in kVA.

The effects of power factor

Power Factor Correction

Consider a canal boat being pulled by a horse. If the horse could walk on water then the angle (Phi) would be zero and COSINE =1. Meaning 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 1 increases and power is wasted, but, as the horse is positioned further away, then angle 2 gets closer to zero and less power is wasted

Why do I need Power factor correction?

Capacitive Power Factor correction (PFC) is applied to electric circuits as a means of minimising the inductive component of the current and thereby reducing the losses in the supply.

The introduction of Power Factor Correction capacitors is a widely recognised method of reducing an electrical load, thus minimising wasted energy and hence improving the efficiency of a plant and reducing the electricity bill. It is not usually necessary to reach unity, i.e. Power Factor 1, since most supply companies are happy with a PF of 0.95 to 0.98

How does it work?

By installing suitably sized switched capacitors into the circuit, the Power Factor is improved and the value becomes nearer to 1 thus minimising wasted energy and improving the efficiency of a plant.

What do I do now?

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Once in place, the cost of PFC can usually be recovered in less than 1 year.