Impact Assessment of High-Frequency Distortions Produced by PV Inverters

Torquato, Ricardo; Hax, Glaucio R. T.; Freitas, Walmir; Nassif, Alexandre B.

doi:10.1109/tpwrd.2020.3031375

Cited by 17 publications

(11 citation statements)

References 16 publications

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“…The occurrence of higher voltage harmonics in power grids causes effects related to the flow of distorted currents through the components of power systems, as well as the effects caused by supplying equipment with voltage distorted from the sinusoidal waveform [38]. Higher harmonic currents flowing through the elements of power networks (lines and transformers) cause additional power losses caused by an increase in the RMS value of current and wire resistance caused by the skin effect and the proximity effect, in the case of transmission lines, or an increase in dissipation and eddy current losses, in the case of transformers [27,[39][40][41]. According to the currently applicable regulations [5,6], the voltage distortion factor THD U value in medium voltage networks cannot exceed 8%.…”

Section: Voltage Waveform Distortionmentioning

confidence: 99%

Analysis of the Impact of a Photovoltaic Farm on Selected Parameters of Power Quality in a Medium-Voltage Power Grid

Hołdyński,

Skibko,

Firlit

et al. 2024

Energies

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Over the last few years, a dynamic increase in the installed capacity of distributed energy sources has been observed, with the largest share being photovoltaic sources. The power grid is a system of connected vessels, and changing the structure of electricity production has a specific impact on the operation of this network, which makes it necessary to study the impact of the sources on the power system. The current and projected increase in the number of connected installations will make the issues of interaction and cooperation of distributed sources with the network extremely important. The article presents an analysis of the impact of a photovoltaic farm on selected parameters of the quality of electricity supply. This analysis was made on the basis of simulation results in a computer program and measurement tests carried out on a real photovoltaic farm with a capacity of 1.8 MW connected to the medium voltage power grid. The impact of the farm-generated power on the values of fundamental indicators of the quality of electricity supply, such as voltage deviations, voltage asymmetry factors, and voltage distortions factors, is presented. These relationships were determined based on the correlation and regression analysis of individual electrical quantities.

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Section: Voltage Waveform Distortionmentioning

confidence: 99%

Analysis of the Impact of a Photovoltaic Farm on Selected Parameters of Power Quality in a Medium-Voltage Power Grid

Hołdyński,

Skibko,

Firlit

et al. 2024

Energies

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“…These levels were extensively discussed and compared in [ 53 ] for distortion caused by EVs during charging operations, considering harmonic and supraharmonic intervals. It is observed that two issues make the definitions of SH limits or compatibility levels more complex: first, the effect of the grid impedance and of resonances with variable factors of merit amplifying or attenuating emissions in terms of voltage and/or current [ 1 , 3 , 4 , 11 ]; second, when comparing values in the harmonic and supraharmonic ranges, the different resolution bandwidth and the narrowband or quasi-broadband behavior of components at different frequencies must be considered.…”

Section: Lessons Learned and Compatibility Levels For The Sh Intervalmentioning

confidence: 99%

“…Depending on the characteristics of the respective sources, such emissions may have varied and peculiar time-frequency and impedance behavior. Paired with the relative difficulty of carrying out comprehensive tests, authors have concentrated mostly on relevant types of sources, such as wind parks [ 1 , 2 ], photovoltaic (PV) parks [ 3 , 4 ], electric vehicle (EV) chargers [ 5 , 6 ], and smart lighting (e.g., LED or fluorescent lamps) [ 7 , 8 ], including the various cases of lighting as victims and sources of secondary emissions [ 9 , 10 ].…”

Section: Introductionmentioning

confidence: 99%

“…Individual emissions may vary with frequency depending on the relationship of the internal converter impedance and grid impedance, also affected by network resonances, as studied in [ 3 , 4 ] for PV inverters and [ 5 , 12 ] for EV chargers on a DC grid. In [ 4 ], it is underlined how much input capacitors of the nearby loads can attract SH emissions that do not consequently reach the point of common coupling with the grid and do not propagate much. This, of course, reduces disturbance to the distant connected equipment, but increases the stress on equipment capacitors, causing aging and premature failures.…”

Section: Introductionmentioning

confidence: 99%

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The Effects of Supraharmonic Distortion in MV and LV AC Grids

Mariscotti,

Mingotti

2024

Sensors

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Since the integration of electronic devices and intelligent electronic devices into the power grid, power quality (PQ) has consistently remained a significant concern for system operators and experts. Maintaining high standards of power quality is crucial to preventing malfunctions and faults in electric assets and connected loads. Recently, PQ studies have shifted their focus to a specific frequency range, previously not considered problematic—the supraharmonic 2 kHz to 150 kHz range. This range is not populated by easily recognizable harmonic components of the 50 Hz to 60 Hz mains fundamental, but by a combination of intentional emissions, switching non-linearities and byproducts, and various types of resonances. This paper aims to provide a detailed analysis of the impact of supraharmonics (SHs) on power network operation and assets, focusing on the most relevant documented negative effects, namely power loss and the heating of grid elements, aging of dielectric materials, failure of medium voltage (MV) cable terminations, and interference with equipment and power line communication (PLC) technology in particular. Under some shareable assumptions, limits are derived and compared to existing ones for harmonic phenomena, providing a clear identification of the primary issues associated with supraharmonics and suggestions for the standardization process. Strictly related is the problem of grid monitoring and assessment of SH distortion, discussing the suitability of normative requirements for instrument transformers (ITs) with a specific focus on their accuracy.

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“…With the massive integration of these VSC devices, there is a concern about their harmonic impact on power systems [5][6][7]. Under the normal condition, VSC devices only produce very-high-frequency harmonics, which is produced by the PWM switching, but such harmonics can generally be impeded by a passive filter in front of the VSC [8,9]. However, VSC devices can generate low-order non-characteristic third harmonics under the unbalanced condition, which is a power quality concern of power systems.…”

Section: Introductionmentioning

confidence: 99%

Modeling of Non-Characteristic Third Harmonics Produced by Voltage Source Converter under Unbalanced Condition

et al. 2022

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A three-phase three-wire voltage source converter (VSC) can produce third harmonics when it is operated under an unbalanced condition. It is essential to understand the mechanism of the production of this third harmonic and to assess its impact on power systems. Therefore, this paper presents an analytical model of the VSC under the unbalanced condition through mathematical derivations, and the final model is a coupled Thevenin circuit. The proposed model allows for direct computation of the non-characteristic third harmonics through harmonic power flow studies. The results show that VSC under unbalanced conditions emits both positive-sequence and negative-sequence third harmonics, and that the positive-sequence third harmonic is much larger than the negative-sequence third harmonic. It also shows that the unbalanced level and the size of the dc-link capacitor are critical to the level of non-characteristic third harmonics. The correctness of the proposed model and its application on noncharacteristic third harmonic evaluations have been verified using EMT simulations.

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Impact Assessment of High-Frequency Distortions Produced by PV Inverters

Cited by 17 publications

References 16 publications

Analysis of the Impact of a Photovoltaic Farm on Selected Parameters of Power Quality in a Medium-Voltage Power Grid

Analysis of the Impact of a Photovoltaic Farm on Selected Parameters of Power Quality in a Medium-Voltage Power Grid

The Effects of Supraharmonic Distortion in MV and LV AC Grids

Modeling of Non-Characteristic Third Harmonics Produced by Voltage Source Converter under Unbalanced Condition

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