What actually are harmonics? Where do they come from? How do the impact the system, particularly the grid? What are the solutions for minimization of harmonics?
This and more in the “Network harmonics” category!
Active filter or AFE drive – What is a better option? When taking care of grid harmonics there are several technical solutions to choose from. You might stand in front of a dilemma: active filter or AFE drive? What is a better choice? Nowadays there are multiple approaches how to Read more
How to understand IEEE 519-2014? IEEE 519 is one of the worldwide most common standards related to harmonics and power quality. Yet, the standard is not always correctly interpreted and sometimes even misused. In this article we bring up few points that will help us how to understand IEEE 519. Read more
How strong is a strong grid? When evaluating the impact of a VFD on the electric grid, particularly the harmonic distortion, we often talk about “strong grid” or “weak grid”. These terms may be a bit vague or at least relative. In this post we try to put the grid Read more
What does purely inductive network actually mean? When calculating network harmonic distortion of variable frequency drives (VFD) there are basically two ways differentiating in complexity and eventually also accuracy. One is a simple harmonic calculation while the other option is a network harmonic study. The harmonic calculation is based on Read more
Harmonic calculation versus network harmonic study As our regular reader you already have a solid knowledge about network harmonics caused by non-linear power electronic systems. It does not surprise you that network might have resonance(s) – a topic that needs to be addressed. Also, you are familiar with harmonic footprint Read more
Active harmonic mitigation with AFE drives In this article we will once again touch the topic of grid side harmonics, particularly focusing on active harmonic mitigation with AFE drives. Abbreviations used: AFE = Active Front End APF = Active Power Filter ASD = Adjustable Speed Drive (synonym to VFD) DFE Read more
Network harmonics: Software tools In order to analyze complex networks with multiple elements and various configurations of the grid a sophisticated software tool is unavoidable. Luckily, there are several good products available on the market. In this article we look closer at software tools for network analysis. In our network Read more
Harmonic filters The continuation of our “Network harmonics” series [1] presents an article about AC harmonic filters. We explain the purpose of harmonic filter. Different types of harmonic filters are shown. Several design considerations are discussed. Main items are illustrated with figures and pictures. Grid side filters are covered in Read more
Network harmonics: Mitigation methods Today’s post focuses on harmonic mitigation methods. Let us review the most common, well proven methods of minimization of harmonic distortion on the grid side. Previous articles presented a general view on harmonics, their origin and effects [1]. The grid side harmonic spectrum of VFDs had Read more
VFD harmonic spectrum Introduction After the theoretical introduction [1] we jump to variable frequency drives as sources of harmonics. This post is about VFD harmonic spectrum. As already mentioned, VFDs belong to non-linear devices with non-sinusoidal currents and/or voltages that they draw from the grid or inject into the grid. Read more