Wed. May 22nd, 2024
Harmonic DistortionHarmonic Distortion

Harmonic Distortions are typical voltage and current abnormalities in electrical distribution networks caused by frequency shifts. There are aberrations from the conventional sinusoidal changes in voltages or currents, in particular. Nonlinear loads, such as those connected with power electronic converters, such as variable frequency drives (VFDs) used for fans and pumps supplying building air conditioning systems, are the principal source of harmonics. These converters, in particular, generate non-sinusoidal current/voltage and bring nonlinear loads into electrical distribution networks.

Harmonic distortions are becoming a prevalent occurrence in buildings due to the widespread use of computers and other power devices. Harmonic distortions, in particular, can create a variety of problems and damages, including wire overheating and power loss.

The utilization of nonlinear loads by end consumers of electricity is the most common cause of harmonic distortions. Nonlinear loads, which include the vast majority of power electronic equipment, draw current in a non-sinusoidal way.

The existence of distortions in current and voltage waveforms has grown more common as the usage of such devices in consumer loads has expanded. The output of the DAC must be collected and evaluated using the test system digitizer and processing resources to check for harmonic distortion.

Power Factor

To convert the collected data into frequency domain information, the DSP system performs a quick Fourier transform. The harmonic content ratio is calculated by measuring the amplitude of the input signal frequency, which serves as a reference point for the frequency domain data obtained by the FFT. The amplitudes of integer multiples of the signal frequency are measured and added, and the results are expressed as a percentage or a dB ratio.

Harmonic filters are resonant circuits in series or parallel that shunt or block harmonic currents. They lower the harmonic currents coming into the power system from the source, lowering the system’s harmonic voltage distortion. These devices are costly and should only be used after other approaches for limiting harmonics have been considered. Filters aren’t always easy to use in a specific context. The filters may interact with the system or with other filters to generate resonances that were previously undetected.

As a result, harmonic studies should be utilized to help determine the kind, distribution, and rating of the filter group in all but the simplest circumstances. Harmonic filters are divided into four categories based on frequency. At high frequencies, ferrite-cored inductors can be employed.

The designer must take great care to ensure that the ferrites do not get saturated, resulting in power loss and core heating. If at all feasible, air-spaced inductors should be used. Air-spaced solenoid wound inductors have no saturation effects and may be utilised from HF to UHF. Radiation and resistive heating cause losses.

Power harmonic filters are primarily used to either block or locally isolate and cancel harmonic currents in electrical power distribution networks (Fuchs and Masoum, 2008). Harmonic filters, in particular, are built with low impedances to guarantee that harmonic currents travel between the loads and the filters instead of reaching the power source and other components of the electrical power generating and distribution systems.