Power Factor (PF) is simply a name given to the ratio of "Actual" Power (the Active Power) being used in a Circuit, expressed in Kilowatts (kW), to the power which is "Apparently" being drawn from the line expressed in kilo volt-amperes (kVA).

i.e. P.F. = kW
kVA

SUBSTANTIATING POWER FACTOR CORRECTION COSTS

Assuming a typical plant has a total load of 500 kW and a power factor of say 0.80 lagging. The average demand charge is R 40-00/kVA in South Africa.

kW
PF
= kVA

Therefore 500/0.8 = 625 kVA maximum demand

0.80 lagging : Total cost @ R40-00/kVA = R 25 000-00/Month

By installing capacitors to improve power factor to say 0.98 lagging.

New costs are 500/0.98 = 510 kVA Maximum Demand

Total costs @ R40-00/kVA = R 20 400-00/Month

Therefore Savings per Month = R 4 600-00

Power Factor correction equipment usually pays for itself within 12 months of the initial purchase and continues saving indefinitely. It therefore stands to reason that more significant savings can be anticipated with the ever-increasing escalating costs of electricity in the future.

All modern industries utilize electrical power in some or other form. Two basic categories of loads are encountered in alternating current (AC) networks. These are Resistive and Inductive Loads.

Technoserve also offer specialised Control Panels, Standby Generator sets, Transformers, reconditioned H.V. Switch gear as well as H.V. Power Factor Correction equipment. All equipment used is of the highest standards.

Our further speciality involves refurbishing of existing Power Factor systems to our uncompromising standards. We also undertake harmonic surveys as and when required.

RESISTIVE LOADS

These are load devices containing only resistance e.g. incandescent lamps, heaters, soldering irons, ovens, geysers, etc.

The current drawn from the Supply is directly converted into heat or light. Since the voltage is assumed to be constant, the actual Power (kW) being used is identical to the Apparent Power (kVA) being drawn from the line. The Power Factor is therefore Unity or 1. In these purely resistive circuits, the current and voltage sinewave peaks occur simultaneously and are said to be "In Phase".

INDUCTIVE LOADS

This encompasses all equipment utilizing an electrical winding, wound in various ways around an iron core, embodying electro-magnetic fields and fed by alternating current (AC) e.g. electric motors, transformers, welding equipment, reactors etc, generate a voltage which is more or less in opposition with the supply voltage and generally out of step or phase with it.

The current drawn from the supply is made up of two separate kinds of current, namely power producing current and magnetizing current. Therefore, the current flowing in an AC circuit (unless corrected) is generally larger than is necessary to supply the power being expended by the plant.