Calculating Power Factor and Best way to improve Power Factor
Table of Contents
Introduction
Why is it necessary to Calculate Power Factor and improve it? When you’re running your own business, it’s really important to be familiar with the energy loss incurred by the poor power factor. Your power factor has major implications on your electricity bills; in fact, it can add plenty of amounts extra to your electricity bills monthly! Knowing how to calculate power factor will help you to upgrade your system performance and pay less money on a continual basis.
The power factor is calculated by dividing total active power (KW) by Apparent Power (KVA), so let’s dive into the details of calculating power factor and its improvement by using different formulas.
how to calculate power factor?
We can define the power factor “PF” as a ratio between active power/real power represented by “P” and apparent power represented by “S”. The power that is used to run machinery and other loads over a specific time duration is termed apparent power.
This specific power is sometimes also referred to as demand load. The power factor is basically the cosine ratio of the angle between the voltage and current at any time. As the angle changes, the power factor also changes. Power factor can be calculated and easily improved by using the below calculations.
How To Calculate Power Factor Without a Watt Meter?
It can be calculated in a lot of ways. Firstly, we need to know what is our system’s total demand or we can also term total kilowatts (KW). From this demand, we can calculate the amperes for the method depending upon the system whether it’s a single-phase or a three-phase system. Read more about three-phase power here.
The next thing is to find out what is our current power factor. To calculate power factor, we can use the following formulas.
PF = cos φ= P / (V × I)
P= Kilo-watts (KW)
V= Voltage in Volts
I= Current in Ampere
As we stated above, the power factor is a ratio of active and apparent power and we can write the formula below.
Power Factor = cosɵ = P (Active Power)/S (Apparent Power)
Here,
P= Voltage x Current ****for single phase
P= √3 x Voltage x Current x cosɵ ****for three-phase
S= Voltage x Current *****in VAR
Let’s have a look at below power triangle to understand the relationship between active, reactive and apparent power to calculate the PF.
Power factor improvement
As we have calculated the power factor by using the active power and apparent power. Now, if this value comes out to be less than 0.9 or 0.85, then the system needs power factor improvement. If the value exceeds 0.9, then the system may be said to be performing efficiently.
If the value comes out to be less than 0.85, then we need to do some calculations. For that first need to calculate the system reactive power at the old power factor. Use the below formula to calculate.
Reactive Power in KVAR = Q (System)= √(S(kVA)2 – P(kW)2)
Now we need to decide on the new calculated power factor value as to which value we want to improve it. By taking that value, calculate the apparent power again and we will call it corrected apparent power.
Apparent power corrected =S(kVA) = P(kW) / PF (selected new)
Again, calculate the reactive power using this corrected apparent power by using the formula below.
Reactive power corrected =Q(kVAR) = √ (Corrected (kVA)2 – P(kW)2)
Now we need to calculate the difference between the corrected and previously calculated reactive power of the system. We will call it the required value of reactive power. Use below formula
Required Reactive Power = Q(Required) = Q(System) – Q(Corrected)
We need to determine the size of the capacitor to improve and calculate the “PF” of our system. To calculate the capacitor size, we can use the below formula.
Capacitor size in Farads (F)= C = 1000 × Q(Required) / (2πf(Hz)×V2)
A More Profound Knowledge of Power Factor Improvement:
Applications of Power factor
This is an important parameter in electrical engineering holds significant relevance across multiple domains due to its impact on system efficiency and energy usage.
In industrial settings, maintaining a high “PF” is pivotal for optimizing power utilization and reducing losses in key equipment such as motors and transformers. This efficiency enhancement directly affects utility billing, especially in commercial and industrial sectors, where penalties for low power factor can significantly impact operational costs.
Beyond cost considerations, “PF” correction contributes to voltage regulation within transmission and distribution systems. This improvement not only stabilizes voltage levels but also enhances the overall quality and reliability of electricity supply.
Efforts to optimize power factor can also result in capacity release within these systems, potentially reducing the necessity for additional infrastructure and minimizing line losses during power transmission.
The integration of renewable energy sources, like solar and wind farms, necessitates aligning power factor to ensure compatibility with the existing grid infrastructure and enhance overall efficiency.
Moreover, “PF” correction in HVAC systems within buildings leads to reduced energy consumption, contributing to sustainability efforts and cost savings. Additionally, its role in minimizing harmonic distortion ensures better power quality, safeguarding equipment and ensuring smooth operations.
Industrially, capacitor banks are commonly employed to rectify power factor, providing reactive power compensation and significantly improving the overall efficiency of electrical systems.
Even in residential applications, power factor correction holds promise for enhancing energy efficiency in various appliances, potentially leading to reduced energy consumption and cost savings for homeowners.
In summary, the applications of “PF” encompass a wide spectrum, from industrial efficiency improvements and utility billing considerations to voltage regulation, capacity enhancement, and the integration of renewable energy sources, making it an integral component in optimizing electrical systems across various sectors.
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