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    Harmful harmonics

    Unsteady waves can quickly lead to shipwreck

    Harmonics reduce power quality, especially in your own company network. This has a negative impact on people, machines and IT. It can be really expensive, and not just in the event of a fire.

    Harmonics are also known as "harmonics" because their frequency is an integer multiple of the 50-heart fundamental oscillation that we have in our power grids. As a result, they add up to create bizarre rhythms in the grid and destroy the aesthetically pleasing sine wave. This is known as "pollution" of the grid.
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    Influence on operational safety

    It wouldn't be so bad if harmonics weren't harmful to devices and machines and even relevant for operational safety. Wouldn't IT systems be checkmated by them and production lines go on strike as a result. Wouldn't even standardized neutral conductors be overloaded by harmonics and lead to cable fires? Despite its lack of popularity, the extensive literature on this subject reads like a thriller!

    But if you have harmonics in your company network, you are not alone, because every network knows the harmonics. However, there is a need for action if there is interference or even danger. The only annoying thing is that these nasty things are easy to hide and it often takes outages and other problems to be dealt with.
    "We had little transparency about energy consumption. But we were also concerned about operational safety. Current harmonics put a strain on transformers and the neutral conductor and, in extreme cases, can lead to damage or fires in the systems."

    Technician from a company in Stuttgart

    From practice:

    Harmonics are usually measured and displayed as the total harmonic distortion in the network (THD). Here, each harmonic is displayed in terms of its ratio to the fundamental. The measurement below in a Stuttgart plant shows a clear abnormality in the fourth and sixth harmonics.

    But what can you do to prevent flickering light and humming fluorescent tubes from reducing the performance of your employees or to avoid having to bring motors to the scrapheap prematurely due to constant heating? And what can you do to avoid having to justify yourself to the insurance company in the event of damage or fire? The solutions are varied and should be well adapted to the situation. Knowing the causes, sources and effects is a good start. High-frequencymeasurements in the company network are important for this. A good analysis helps to evaluate and find solutions.

    Modern consumers are changing the rules of the game

    For those interested in more detail: The alternating current in the German transmission grid describes an almost perfect sinusoidal curve with a frequency of 50 Hz. Neither transformers nor light bulbs, neither heating elements nor synchronous motors have any significant influence on the sine wave. However, modern consumers are changing the rules of the game in the grid.

    Harmonics deform the required fundamental oscillation. The consequences are manifold, often even serious and expensive. Harmonics are also sinusoidal curves with an integer multiple frequency of the 50 Hz fundamental. Their frequency can therefore be 100, 150, 200, 250 ... hearts, so they add "harmonically" to each interval of the fundamental oscillation. Because of their similarity or multiplicity to the 50-heart amplitude, they are also referred to as the 2nd, 3rd, 4th, 5th to nth harmonics.

    Distortions of the sine curve

    The main cause of distortion of the aesthetically pleasing sine wave is electronics, because it cannot do anything with waves, but requires a constant DC voltage. This is generated in power supply units with capacitors and other components. The capacitors are charged with a short current pulse in each wave of the fundamental oscillation. This results in distortion of the sine wave and harmonics of any variation. Switch-on processes and starting currents of machines, such as frequency regulators and dimmers, also contribute to the contamination of the mains frequency.

    Different sources of interference usually result in typical harmonics. If, for example, you want to call the consultant of your choice and the telephone system goes on strike again, this could be due to harmonics of the 20th to 30th harmonic, because they like to put telephone systems out of action!

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