Power factor, in relation to electrical systems, defines the overall efficiency and economy of your consumed energy. From a commercial facility or industrial operation to the house owner who simply wants to know how he can make his house’s energy usage more efficient, understanding power factor is crucial. It will discuss what a power factor is, why it is important, and how it could help you improve electrical efficiency.
Power factor expresses something about how much electrical power is being converted to work output. It can be defined as the ratio of real power to apparent power. Mathematically, it can be represented as:
Power Factor Triangle
Analogy of Power Factor
Let’s look at a simple analogy to better understand these terms. Say you ordered a glass of your favorite beer. The drinkable, thirst-quenching part of your beer represents Real Power, kW. Unfortunately, with your ale comes a little bit of foam that doesn’t quench your thirst, representing Reactive Power, kVAR. The total contents of your glass, KVA, is the sum the beer, kW, and the foam, kVAr.
The power factor is the ratio of Real Power to Apparent Power.
Same with the ratio of beer to the foam and the beer in a glass. For a given power supply, kVA, the more foam you have, that is, the higher the percentage of kVAR, the lower will be your ratio of kW, beer to kVA, beer plus foam. Thus, the poorer your power factor. The less foam you have, percentage-wise, in kVAR, the higher your ratio of kW to kVA to kVA and the better your power factor. As your foam, or kVAR, approaches zero, your power factor approaches 1.0, or unity.
The power factor values range from 0 to 1, or 0% to 100%. A power factor of 1, or 100% means the whole power supplied is effectively being used which again is an ideal case.
Importance of power factor
Energy Efficiency
If the power factor is great, more of the power will be doing work; if the power factor is small, too much of the power will be wasted in reactive power—hence causing inefficiency, which results in higher consumption of energy.Cost Implications
Most utility companies charge an extra amount to consumers who have a poor power factor. This charge, referred to as a power factor penalty, may significantly increase the amount on your electricity bills. Improving your power factor will help you eliminate these extra charges and achieve better financial efficiency.System Capacity
The low power factor causes overheating, resulting in overload conditions on systems, reducing their capacity and increasing the cost of maintenance. Improvement in power factor reduces loading on transformers and generators, hence increasing their lifespan and decreasing frequent repairs.Factors Affecting Power Factor
Inductive Loads
These are devices like motors, transformers, and inductors, which require reactive power to be present for their operation, hence affecting the power factor. Most inductive loads cause a lagging power factor, wherein the current lags behind the voltage.Capacitive Loads
The disturbances caused by inductive loads can be counter-balanced by a capacitor. They have the ability to supply reactive power into the system to enhance the power factor.Harmonics
Non-linear loads, such as those created by most electronic devices, can inject harmonics into the system. Harmonics cause current waveform distortion and usually lead to a power factor problem as well.How to Improve Power Factor
Install Capacitors
Adding capacitors to the electrical system will offset some of the inductive effects of particular loads and raise the power factor. Capacitors are sources of reactive power that shall balance the inductive reactive power, bringing the power factor closer to unity.Use Power Factor Correction Devices
There is special equipment, called a power factor correction device, that will automatically switch the amount of reactive power in a system to ensure the proper power factor.Regular Maintenance
Maintaining your electrical equipment ensures an efficient power factor. Since regular inspections and maintenance would prevent such problems that may lead to poor power factor conditions, they are essential.Upgrade Equipment
State-of-the-art, energy-efficient equipment tends to have a higher inherent power factor than older, less efficient units. Upgrading to this equipment will often raise the overall power factor of your system.Understanding and managing your power factor can be important in maximizing energy efficiency while reducing operational costs. Maintaining an optimal power factor enables one to maximize the efficiency of electrical systems, eliminate extra charges by utility companies, and lengthen equipment life.
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