Posts Tagged ‘harmonics’

Harmonics in electrical systems (back to basics)

August 16th, 2013 | 1 Comment | Posted in Power quality
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Introduction

Presence of Harmonics in electrical circuits over the years has become one of the most important areas of concern for almost all the utility companies world over. Keeping harmonic levels as minimum as possible is extremely important for healthy grid operations. Let us examine the aspect of Harmonics in detail.

What is Harmonics?

We all know that the electricity generated and distributed takes a sinusoidal wave form. This wave form is generated at a frequency of 50 cycles / second (or 50 Hz). It is also known as main/fundamental frequency waveform. This is the ideal waveform that is suitable for smooth operations of various electrical equipments, appliances connected to the grid.

However, due to various reasons that will be discussed in next section, this pure sinusoidal waveform gets distorted. Additional waveforms (unwanted) get added on top of the fundamental sinusoidal waveform. A Fourier Analysis of these waveforms reveal that these waveforms are in multiple of the fundamental sinusoidal waveform frequency of 50 Hz. These frequency components that have higher frequencies than fundamental frequency are called “Harmonics”.

Figure below shows Fundamental Sinusoidal waveform and an example of distorted waveform containing harmonic component:

Distorted waveform with harmonics

Distorted waveform with harmonics

Sinusoidal waveform

Sinusoidal waveform

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Harmonics overview

October 12th, 2009 | 10 Comments | Posted in Power quality
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Why harmonics problem?    3 types of solutions!      How to make a choice ?     Any software tools ?

Typical distorted current waveforms

Typical distorted current waveforms

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Harmonics current mitigation of electrical system

May 4th, 2009 | 12 Comments | Posted in Power quality
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When professionals want to manage an electrical system in a new installation or after retrofit or extension of an existing installation, it is important to consider the Harmonic currents emitted by the non linear loads connected to the distribution system.
The non linear loads or products producing harmonics can be as example, for industrial equipments: welding machines, battery chargers, variable speed drives for electrical motors, uninterruptible power supplies, or for office equipments or household appliances: TV sets, fluorescent lighting, light dimmers, etc…
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How green are Compact Fluorescent Lights (CFLs)?

April 27th, 2009 | 40 Comments | Posted in Energy Efficiency - lighting, Energy Efficiency - news
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Back on this  subject…

fluorescent lightSome countries and states like Australia, California, and the European Union plan in the near future to ban incandescent light bulbs, to the benefit of  Compact Fluorescent Lights, Lamps (CFLs).
There are two main advantages given by Fluorescent bulbs (CFLs) : …

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Harmonic filter for better power quality

April 16th, 2009 | 65 Comments | Posted in Power quality
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Power Quality Optimization with Active Harmonic Filter :

principle drawingIt is widely believed that active harmonics filters (AHF) are very costly and, therefore, are the last choice for power quality solutions.  The answer is it depends.  Every harmonics mitigation and power factor correction device has its place in the market.

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