Posts Tagged ‘reactive power’

Are Power Factor Correction Units Necessary For Residential Consumers? (Debate)

December 8th, 2014 | 5 Comments | Posted in Power quality
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Few weeks ago, we received this debate from Martin M., one of the visitor of the blog. So here is his interesting opinion on Power Factor Correction…

You too can send us a mail if you want to create a debate on the topic of your choice.

Are Power Factor Correction Units Necessary For Residential Consumers

You may have come across a nice, clear video on the importance of purchasing Power Factor Correction (PFC), also known as KVAR units for residential consumers. You may be luckier and actually met a salesperson, all verbose on how you can save a lot of money by installing a simple device between the power supply and the home appliances.

The selling point implicitly relies on people’s ignorance, as well as well laid-out misinformation and skewed facts. The main selling points for the scammers include the following

  • Home appliances such as refrigerators and washing machines are induction equipment and thus draw reactive power from the system.
  • Many industries use the PFC units to save energy, and so should you.
  • There are a number of positive ‘testimonials’ from satisfied clients.


Using Capacitors in Electrical Circuits

July 29th, 2013 | 1 Comment | Posted in Electrical distribution
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Use of Shunt capacitors in a High Tension (HT) or Low Tension (LT) installation has become a necessity and also mandated by most of the utilities worldwide. Let us understand some concepts behind the use of a Shunt Capacitor.

Need for Capacitor Installation

There is a growing need for energy conservation and all efforts are being made towards the same. On the other hand, the electrical loads in almost all categories of customers i.e. Industrial, Commercial, Residential, Agricultural are inductive loads in nature.

These inductive loads include: electrical equipments and devices like: Induction Motors, Fans, Industrial A.C. machines. With the advent of technology and greater level of automation in the last few decades, the electrical load mix is greatly becoming Inductive in nature.

The drawback of these inductive machines is that they draw a huge amount of Reactive Power (KVAr) from supply side, thus causing lowering of Power Factor (P.F.).


Reactive Power Management

July 11th, 2013 | 1 Comment | Posted in Power quality
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Reactive power management 1

In an AC circuit, there is a likelihood of interrupted direction reversal of the energy flow because of the temporary energy storage in inductive and capacitive parts.

The real power is the power flow left after it has been equally distributed in an AC waveform which in actual can be further utilized to do work such as heating an element and to overcome friction in a running motor.

However, the reactive power is the power flow which is due to the inductive and capacitive network elements; it is first temporarily stored and then returned back to its origin.

Inductors consist of a large coil and are devices which have the capability to store energy in form of magnetic field. On application of voltage, magnetic field is produced across the coil and after some time the current attains its full value. The voltage, so, surpasses the current in phase. Such devices are said to be the ones absorbing reactive power.

Energy storage in form of an electric field is the work of a capacitor. Full voltage difference is reached in some time until a charge is built up when the current is driven through the capacitor. As a result, fluctuation in voltage through the capacitor is observed which is opposed by it causing the voltage to fall behind current in this case. This is therefore referred to as the generation of reactive power because the voltage experiences drop back from current this time.

Reactive power flow occurs due to the energy storage in network inductive and capacitive elements. Voltage level is greatly affected by the reactive power flow throughout the network. As a result there is a need to properly monitor and manage the voltage level and reactive power flow so that the network operation is held within appropriate limit.


VAR & Its Applications

April 10th, 2013 | Make a comment | Posted in Electrical distribution
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The Premise

When there is a higher current flowing through the transmission line, there is a problem with the increase in transmission loss. With more current flow, there is a problem with heat generation. This also causes an increase in the resistance as well.

VAR Compensator

VAR & Its Applications 1

The abbreviation VAR stands for Volt Ampere Reactive or as commonly referred to as the reactive power. The purpose of this device is to provide a rapid reactive power in the case of high voltage electrical transmission networks. Such devices are generally the part of regulation and stabilization. For instance, they are an integral part of the flexible AC transmission system device family.

As far as the physical construction is concerned, there are no major rotating parts. This is different from the case of a synchronous condenser where there is a rotating part (electrical machine). The synchronous model was used previously and in combination with capacitor banks accounted for the power factor compensation.


AC Power (back to basics)

March 20th, 2013 | 1 Comment | Posted in Power quality
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AC power in any electric circuit is the rate of flow of energy at a specific part of that electric circuit. As we all know, the electric energy flow from the generation side toward the consumer load side. But some part of this energy is bounce back to generation side and some part is completely utilized by the load.

Electric power energy that oscillates between source and load is known as reactive power while completely utilized electrical power energy is known as real power. Both the reactive power and real or active or true power are related with the apparent or total power through the following figure.

AC Power 1

From the figure, it can be deduced that;

(Total Power)² = (True Power)² + (Reactive Power)²

Or (kVA)² = (kW)² + (kVAr)²


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