Power factor (PF) is a measure of how much of the electrical current supply is used to do physical work in alternating current (AC) electrical circuits. It is defined as the ratio of the real power (the power that does work) to the apparent power (the total power based on average Volts x average Amps). A power factor of 1 means that all of the power is being used for work, while a power factor of 0 means that no power is being used for work.

For example, electric motors typically work at a PF of 0.8 at maximum power.  A 100kW motor will deliver 100kW of real power but because it has electrical inductance which requires inductive reactive power, additional Amps are supplied resulting in an apparent power of 125 kVA

There are several ways to measure power factor. Here are some of the most common methods:

• Current and voltage measurement: This method uses current and voltage meters to measure the real power based on the instantaneous Voltage x Amps and the apparent power based on the average Voltage x the Average Amps. The power factor is then calculated using the following formula:

Power factor = real power / apparent power

• Power meter: A power meter is a standard instrument that can measure power factor. These instruments typically have several features, such as the ability to measure real power, apparent power, reactive power, and phase angle.
• The power factor can also be calculated from the phase angle between the voltage and current of the AC supply.

When measuring power factor, be aware that it can change during the operating cycle of equipment.

There are several reasons why an application might have a poor power factor. Here are some of the most common reasons:

• Inductive loads: Inductive loads, such as motors and transformers, draw a large amount of reactive power. This reactive power does not do any work, but it does add to the current demanded from the supply resulting in increased apparent power, which can lead to a low power factor.
• Light loads: When motor is lightly loaded, the inductance is the same, but the real power used is lower, which results in a lower power factor. For example, if a motor is only using 50% of its rated power, the reactive current and reactive power required by the inductance will be the same, whilst the real power will reduce by 50%, resulting in the apparent power being reduced by 28%.  This results in a power factor of 0.55.
• Harmonics: Harmonics are distortions in the current waveform that can cause a low power factor. Harmonics are often caused by electronic devices, such as computers and fluorescent lights.

Here are some of the signs and symptoms of poor power factor:

• High current: The current drawn by the load may be higher than expected.
• Overheating: Electrical equipment may overheat due to the higher current draw.
• Voltage fluctuations: The voltage may fluctuate due to the higher current draw.
• Harmonics: Harmonics are distortions in the current waveform that can cause problems with electrical equipment.
• High demand charges: The utility company may charge higher demand charges for a poor power factor.

• Reduced electricity bills: A low power factor means that the factory is using more reactive power than it needs, which can lead to higher electricity bills. Power factor correction equipment can help to improve the power factor and reduce the amount of reactive power being used, which can lead to lower electricity bills.
• Increased efficiency: A higher power factor means that the factory can add more equipment to the same power supply if the power factor is improved.
• Reduced stress on power supply: Reactive power can cause unnecessary stress on electrical supply and associated equipment, which can lead to premature wear and tear. 
• For a factory with a limited kVA supply, more equipment can be run on that supply if the power factor is closer to 1.

If you are using fixed capacitors these will compensate for inductance in your equipment, but you may need an electronic system to control the power factor. Fixed capacitors have a fixed capacitance, which means that they cannot be adjusted to compensate for changes in the load. An electronic system can be used to switch in and out the capacitors, which can help to maintain a good power factor even when the load changes.

Even if you are using automatic capacitors, an electronic system can still be beneficial. An electronic system can provide additional features, such as:

• Remote monitoring: An electronic system can be used to remotely monitor the power factor of your application. This can help you to identify problems early and take corrective action.
• Alarms: An electronic system can be used to generate alarms when the power factor falls below a certain threshold. This can help you to prevent problems, such as voltage fluctuations and overheating.
• Automatic switching: An electronic system can be used to automatically switch capacitors in and out of the circuit. This can help to optimize the power factor and reduce power losses.

The installation of power factor correction electronics will vary depending on the specific application. However, there are some general guidelines that can be followed.

• The location of the power factor correction electronics should be as close to the load as possible. This will help to minimise the power losses in the cables.
• The power factor correction electronics should be installed in a cool, dry location protected from weather and extremes of emperature
• The power factor correction electronics should be installed by a qualified electrician familiar with your application.

Here are some of the most common places where power factor correction electronics are installed:

• At the load: This is the most common location for power factor correction electronics. The capacitors are installed in parallel with the load, which helps to reduce the reactive power drawn by the load.
• At the distribution board: Power factor correction electronics can also be installed at the distribution board. This is a good option for applications with multiple loads.
• At the main switchboard: Power factor correction electronics can also be installed at the main switchboard. This is a good option for applications with a large number of loads.

Yes you can. There are two main types of application.

Typical power systems such as diesel generators and 3-phase battery power supplies will deliver both maximum real and maximum apparent power when the power factor is 0.8. If the power factor of the load is low then the power system will be limited by the current that is supplied rather than the real power that the engine or battery can supply. This will result in a larger power system being required to meet the current demand which increases costs. With a PFC system added, the excess current can be supplied by the PFC system such that the supply works at a PF of 0.8 to provide both maximum real and apparent power.

In particular PFC systems can assist in the transient reactive currents which are required to start a direct on line (DoL) or star-delta motor, enabling a much smaller supply to be used with large motors. This feature can be provided by a PFC and is integrated into Peak Power 200.

For wind turbines without integrated PFC, the PF of the generated power can be fixed due to the characteristics of the generator. Adding capacitors can crudely adjust the power factor. In order to use the power to supply a site, the power must meet the PF required by the site, or to deliver power to the grid, the PF must meet what the Distribution Network Operator target PF. Adding the PFC system enables the power output to be delivered at the required target power factor even as the power output changes with wind speed etc.