What is Power Factor?

Power factor is the measure of how efficient the incoming power is when used in an electrical installation. Power factor contributes to power quality, so a poor power factor means the efficiency of your power within the equipment will be low. It is the ratio of active to apparent power. So, let’s define some terms to break it down:

Active power:

The useful power, one that can be used for lighting or pumping of water, for example. Measured in Watt or Kilowatt (kW)


Reactive power:

The stored power that does not do any useful work. Measured in Var or Kilovar (kVAR)


Apparent power:

The sum of active and reactive power. Measured in Volt Amperes or in KiloVolt Amperes (kVA)


Here is an analogy to make it simpler. Take a packet of crisps. Within the packet there are the crisps themselves and the packet is also filled with air. The crisps represent the active power, it’s the ‘useful’ part in power, or the part that we will be eating. The air in the packet represents the reactive power. This part isn’t ‘useful’ or one that won’t be consumed by you. The packet as a whole (including the crisps and air) represents the apparent power. Unfortunately, you can’t have active power without reactive, just like it’s difficult to have a packet of crisps without air inside (unless it was vacuumed packed of course)!

It’s always disappointing when there is more air in a packet of crisps than the crisps themselves! When relating this to power factor, the more air in the packet, the more reactive power we have, which means the power quality is low. The less air in the packet, the less reactive power we have, meaning that our power quality is high, and our power generation equipment is efficient.

If your equipment is more efficient it leads to lower electrical costs! This is because poor power quality leads to many failures and instability within the grid. These can be problems with the current or cabling, which means time, money and supplies are wasted due to unnecessary maintenance and repair work required to fix these issues. So, having a high power quality will not only save you money, but it’ll also protect your site from unnecessary electrical faults.


Power Factor Correction

So, what can you do to save time and potential losses? To improve your power quality, your systems must have power factor correction equipment installed and connected.

This process involves the connection of capacitors which reduces the electrical load of the distribution system of power. The capacitors produce reactive energy in opposition to the energy produced from loads such as motors. The capacitors stop the reactive energy from transmitting through power generation equipment and the transmission network. It is then redirected towards the motors, for example, meaning that there is now no unnecessary current circulation.


What are the benefits?

It will reduce your electricity bills:

Failures in cabling and changes to the current due to poor power factor can result in penalties from the electrical distribution network. PFC equipment eliminates this issue and reduces power losses.

It allows for more available power:

A high power factor means your electrical installation is will be optimised and efficient. Less wattage is required to produce the same amount of power from a motor.

There are reduced voltage drops:

Installing capacitors reduces voltage drops and redirects the reactive energy back into the motors and not to your essential power generation equipment.