Calculation and simulation of expected Total Harmonic Distortion
As a Power Quality specialist, HyTEPS also performs THD simulations. THD is an abbreviation of Total Harmonic Distortion. We can distinguish between THDu and THDi, where the final letter indicates distortion in the voltage (u) or current (i). THDu indicates Total Harmonic Distortion in the voltage and is one of the most important Power Quality phenomenon present in electric installations.
When changes are made to existing installations, or when there are plans to expand an installation, insight into expected harmonic distortion is particularly valuable. This is also the case with new installations. We offer you insight and advice based on our THD simulations, allowing you to take timely measures to limit harmonic distortion, thus preventing unnecessary problems and unforeseen costs.
Total Harmonic Distortion is expressed as a percentage, which indicates how much of harmonic voltage/current is added to the fundamental (50Hz) voltage/current. It is calculated using the following formula:
Total Harmonic Distortion in the voltage (THDu)
Total Harmonic Distortion (THD) in the voltage (u) is directly related to the reliable functioning of electrical equipment. Several standards, such as the NEN-EN50160 / IEC61000 series, not only set limits for Total Harmonic Distortion in the voltage (THDu), but also for the maximum individual harmonic voltages. According to the EN50160 standard, THDu should not exceed 8% for 95% of the time during a given week.
Subject to installation changes and expansion
In practice, THD is usually measured after an electrical installation has already been commissioned, or in the event of problems occurring within an installation. If an installation meets the standard for harmonic distortion at a certain moment, that does not necessarily mean this will always be the case; an up to date THD simulation is, therefore, recommended. In fact, complying with THDu standard limits does not ensure that everything in an electrical installation is functioning properly. From experience, we know problems such as malfunctions or failures of sensitive electrical equipment, may still occur when values are within limits set by the standard.
Many electrical installations are adjusted and/or expanded over time. For such adjustments or expansions, the effect on THD should preferably be examined. In these cases, determining THD by means of simulations offers a solution.
Take measures at an early stage
Combining professional software, previous measurements in the installation, and our technical knowledge in the field of Power Quality, we can predict what the THD value will be following a specific modification or expansion in different types of installations.
With the help of THD simulations, the necessary adjustments and measures can be taken at an early stage to keep THD within specified limits. This not only keeps harmonic distortion under control, but also helps prevent unnecessary costs.
Correct information and associated parameters are decisive for performing an accurate THD simulation. With the right information and parameters, HyTEPS determines the best approach, based on your specific situation.
We have been providing Power Quality simulations for many years. Our engineers identify the problem and HyTEPS delivers the best-fit solution. Our relations are in a wide range of sectors, including industry, hospitals and offshore. We have worked out some of our cases for you. Click on the case and read more about the challenge, our solution and the results.
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