Power Factor Correction Capacitors and How They Save Energy

power factor correction capacitors
power factor correction capacitors

In this article we will discuss the benefits of power factor correction capacitors and their positive impact on our energy spending.

If you have been asked to improve the energy efficiency of your business to reduce your electric bill, you may have considered correcting the energy factor. Power factor corrections used in the right conditions can have serious consequences for power consumption. However, its effect is highly dependent on the current power factor and operational variables. Some basic research and calculations are required to determine if a power factor correction is appropriate and what type of power factor correction is appropriate.

We’ve compiled a list of frequently asked questions about power factor to help you understand whether and how to actually perform a power factor correction right for your situation. With this knowledge, you can make business decisions with confidence.

Frequently asked questions about power factor correction:

What is the strength factor?

the ratio between active power (kW) and apparent power (kVA) is called Power Factor. In other words, it is the relationship between the amount of power flowing through the system/device (kVA) and the amount actually used to perform its function (kW). The energy component of the apparent energy wasted is known as the reactive power (kVAR).

What is power factor correction?

Power factor correction is a term for all equipment that compensates for reactive power and improves the power factor ratio. For example, Power Factor Correction Capacitors.

Why do we need to improve our strength factor?

As a customer of the electricity market, commercial and industrial utilities (or utilities) are charged for all energy consumed, but not all of that energy does a useful job. By offsetting the power factor, the waste energy consumption is greatly reduced, and business costs can be saved.

Note: The level of saving depends on the amount of reactive power in the electrical installation before the rectifier is installed.

What is the reason for the weak power factor?

Inductive loads such as electric motors, ballast lights, and transformers cause low (low) power factors. In addition, inductive loads that are not used at or near design capacity contribute significantly to the lower power factor.

The low power factor generally results from the large reactive power of the system.

What is reactive power?

Reactive power is considered “wasted energy” because it does not perform any useful work on the system. The higher the reactive power fraction, the lower the power factor.

The types of energy are divided as follows.

Active or real power (kW) = the ability to perform useful work

Reactive capacity (kVAR) = the ability to do no useful work

Apparent force (kVA) = vector sum of active and reactive force. This is what we pay for

Power factor = sine and cosine of the angle between the active energy vector and the apparent force vector

Reducing reactive power

Note: If the compensation (power factor compensator) can reduce the reactive power component, and thus the phase angle, the apparent power vector length will be shorter, resulting in lower power consumption and power charges.

How can I find out the power factor now?

Information on consumption in kilovolt-ampere-hours (KVAh) and kilowatt-hours (KWh) is typically available at commercial and industrial installation power rates or by requesting a power company. Retailers need to be able to provide enough information to estimate potential savings in consumption.

A measurement period is recommended to evaluate accuracy and harmonics. You need to check each cycle of the installation. One week is usually enough. Or, if your business is seasonal, you need to compare these periods.

Note: Interpreting the consumption log for power factor calculation can be complex and require engineering and mathematical skill sets. There is no one way, as each retailer provides this information in different formats.

Did you know? The power factor is not constant. Power factor fluctuates from second to second and can be affected by process changes such as engine load.

What is an optimum score?

A power factor close to 1 (1) is a good power factor with little power wasted, while a power factor close to 0 represents a system in which most power is wasted.

In general, a power factor of 0.8 or higher is considered an appropriate power factor. It is less than 0.8 and needs to be adjusted to save consumption and comply with the requirements of the power grid operator.

How can I improve my power factor?

Power Factor can be made better through various methods. Some include:

  • Upgrade or replace inductive loads that are not operating close to design capacity
  • Correction of local power factor under load
  • Capacitive central correction
  • Static constant generator (effective power factor correction for delay power factor)
  • Active power filter (phase balance, harmonic correction, active correction of leading and delay power factors)
  • Using a variable speed drive (VSD) to control the electric motor
  • Use equipment like capacitors

How can I monitor improvements?

By measuring the base current of the load, you can directly check the consumption in real-time. Over time, this will be reflected in the electricity tariff as a reduction in consumption, specifically in the apparent consumption of energy (kVA).

How much does power factor correction cost?

The cost of power factor adjustment depends on the amount of reactive power in the system. The higher the reactive power component, the more equipment is required to perform the compensation.

It is important to remember that every installation requires a tailored solution.

How long does it take to get a rate of return on investment?

The cost recovery of the capital cost of compensator installation depends on the demand of the installation and the operating capacity factor. The lower the power factor, the higher the repair cost.

However, the lower the power factor, the greater the potential savings and thus the return on investment can be seen in a shorter time frame.

How much power factor correction can save power consumption?

For example, a customer’s water treatment plant attempted to improve the power factor by using an active power filter (APF). With a very low power factor of 0.61, there was a great savings opportunity. When the APF is turned on, the consumption is immediately and continuously reduced by 35-40%.

What should I keep in mind when considering a power factor correction?

There are a few things to consider before you start correcting the power factor.

Careful consideration must be given to adding new active technologies to equipment with existing capacitive compensation. Most active technology manufacturers recommend removing the old technology before installing it. Power factor correction capacitors reduces consumption only if the system has a large percentage of reactive power. Power grid providers have rules regarding minimum power factor. They must be taken into account when designing or modifying equipment.


Commercial and industrial sites with many inductive loads should consider power factor compensation along with other methods to reduce consumption, such as load changes, business operations, and employee behavior. As a first step, the most important change we can all make to save energy and improve sustainability is to “turn off” or shut down its cold room when it’s not in use. Then after that we can use power factor correction devices, like the power factor correction capacitors to further increase the savings.



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