Study Of Harmonic Distortion Research Articles

Simulation-based probabilistic-harmonic load flow for the study of DERs integration in a low-voltage distribution network

<abstract><p>The integration of distributed energy resources (DERs) and, therefore, power electronic devices into distribution networks leads to harmonic distortion injection. However, studying harmonic distortion solely through deterministic approaches presents challenges due to the inherent random behavior of DERs. This study introduced a strategy that leverages PowerFactory's harmonic load flow tool. By combining it with Python co-simulation, probabilistic load flows can be developed. These load flows utilize current sources to represent harmonic distortion emitters with predefined harmonic spectra. The proposed strategy was implemented on a real network, where two different capacities of DERs were integrated at various locations within the network. The distributions for the total harmonic distortion of voltage ($ THD_{v} $) and the total harmonic distortion of current ($ THD_{i} $) were obtained 24 hours a day in nodes and lines of the network. The procedure allowed considering the uncertainty associated to the DERs integration in distribution networks in the study of harmonic distortion, which, speaking from a simulation approach, is scarce in the literature.</p></abstract>

Study of harmonic distortion from variable speed drive and energy saving lamps

The power <span>electronic component has been widely used in the current industrial era. It has been considered more efficient than the previous devices as it saves more space and uses less power. One example of power electronic components is the variable speed drive for speed regulation of electric motors in the industrial world. Another application of power electronic components is to be used in energy-saving lamps. The use of power electronic components in these two loads generates harmonic distortion and reduces network power quality. In this paper, the authors analyzed the harmonics in both loads. As a result, the total harmonic distortion (THD) current for four energy-saving lamps is 88.3%. Meanwhile, the THD current at the 50 Hz, 5 A, and variable speed drive is 46.2%. After mixing the two loads, the THD current decreases by around 35%.</span>

Hybrid Dual and NPC Six-Phase Drive Systems

This paper presents two hybrid six-phase machine drive systems. The topologies are considered to be hybrid because two three-phase groups of the machine are fed by different types of converters. The purpose of these topologies is to be alternative configurations, being midway between the conventional six-leg two-level (2L) inverter, composed of 12 switches, and more complex structures, such as the six-leg three-level neutral point clamped (3L-NPC) inverter, composed of 24 switches and 12 clamping diodes, or the conventional 12-leg dual inverter, composed of 24 switches. One of the hybrid topologies is composed of 18 switches and the other is composed of 18 switches and 6 clamping diodes. A comparative study of harmonic distortion, semiconductor losses, and machine torque ripple is performed. Compared with the conventional 2L inverter, the proposed systems provide better performance in terms of harmonic distortion, overall semiconductor losses, and machine torque ripple and are less complex than dual and NPC inverters. Pulse width modulation (PWM) strategy is discussed and simulated. A modification in PWM strategy of the hybrid configurations is performed in order to obtain similar torque ripple to the cases when dual and 3L-NPC converters are used, even with lower number of semiconductor devices. Experimental results are also presented in order to validate the PWM strategy.

Study of harmonic distortion on impulse response measurement with logarithmic time stretched pulse

Study of harmonic distortion on impulse response measurement with logarithmic time stretched pulse

Investigation of AC/DC converter harmonics by an analytical based time-discrete approach

By investigating AC/DC converter harmonics in more detail, the interaction of AC and DC side as well as nonideal conditions have to be considered. This paper proposes a time discrete approach, which allows one to calculate analytically the steady state DC currents at the firing points of each thyristor, if voltage harmonics or asymmetries disturb the ideal operation conditions. This forms the basis for an effective and accurate evaluation of AC/DC converter harmonics, especially for the investigation of parameter dependencies and for the application in harmonic distortion studies. Selected examples demonstrate particularly the analytical description of the discrete DC currents.

Harmonic distorition caused by electrode polarisation

Steady-state measurements of the electrical properties of electrodes immersed in physiological saline were taken with small- and large-amplitude sinusoidal voltages (30 m V-1 V) in the frequency range 0.2 mHz-2 Hz. Impedance magnitude and phase, and the first four Fourier series coefficients of the polarised current were measured. The dependence of the polarisation admittance on input current intensity was modelled with the linear relationship proposed by Schwan. This model predicts harmonics in the non-linear range for AC overpotentials up to several hundred millivolts. Observed values deviated from theoretical values. Reasons for such deviations are discussed. The study of harmonic distortion appears to be a useful tool to monitor and predict the non-linear behaviour of the interface and other dielectric phenomena.

An introduction to the study of harmonic distortion in audio frequency transformers

An introduction to the study of harmonic distortion in audio frequency transformers