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Understanding Power Factor
In most modern electrical distribution systems, the predominant loads are resistive and inductive. Resistive loads are incandescent lighting and resistance heating. Inductive loads are A.C. Motors, induction furnaces, transformers and ballast-type lighting. Inductive loads require two kinds of power. Active (or working) power to perform the work (motion)and Reactive power to create and maintain electro-magnetic fields. The vector sum of the active power and reactive power make up the total (or apparent) power used. This is the power generated by the utility for the user to perform a given amount of work.
Active power is measured in KW (1000 Watts).
Reactive power is measured in KVAR (1000 Volt-Amperes Reactive).
Total Power is measured in KVA (1000 Volts-Amperes).
Power factor then is the ratio of active power to total power as demonstrated in the following diagram.
Improving Power Factor
Power Factor Optimization requires the addition of power factor correction capacitors to the power distribution system. These capacitors act as reactive power generators, and provide the needed reactive power to accomplish KW, or Active Power work. This than reduces the amount of reactive power, and thus total power, generated by the utility. Let’s look at an actual case of power factor improvement to an industrial plant, and the savings results. Take the case of a utility that adds a surcharge when the power factor falls below 85, which is not at all uncommon. Because the utility applied a penalty formula the customer faced an additional charge of $650.00 per month. The businesses requirements were 812KW of work which meant that the 1500KVA transformer power factor was 78 loaded as shown in the first diagram below. The customer then added capacitors, and improved their power factor, thus eliminating the monthly surcharge.
This would be an annual savings of $7,800.00. The utility has to generate 247 less KVA (1160 – 913 = 247), and the user has made their 1500KVA transformer more efficient, thus allowing them to increase productivity without risking a power factor surcharge.
In the Simplest Terms...
Power Factor could be compared to a horse pulling a train. Because of the tracks, the horse is required to be in an offset position. As the horse pulls, the train moves forward, creating the Active, or working Power. Because the horse is offset, there is some loss of efficiency, resulting in the apparent or Reactive Power. If the horse moves closer to the tracks, it will improve how efficiently it moves the train forward, achieving a power factor correction.
Real Life Application
Power Factor optimization has been tested by the Department of Energy and NASA. The following diagram reflects power utilization in a real life application. In addition to providing the whole home surge protection and the potential for substantial cost savings, you can also see that our products clean up the power, or reduce noise and spikes, which is imperative with today's high dollar electronics such as PC's and plasma televisions. In the example below, the total savings was 24%.
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