scholarly journals Method for Evaluation of the Utility’s and Consumers’ Contribution to the Current and Voltage Distortions at the PCC

Energies ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 8416
Author(s):  
Yaroslav Shklyarskiy ◽  
Iuliia Dobush ◽  
Miguel Jiménez Carrizosa ◽  
Vasiliy Dobush ◽  
Aleksandr Skamyin
Keyword(s):  
Power Supply System ◽  
Experimental Tests ◽  
Nonlinear Loads ◽  
Harmonic Currents ◽  
Wide Range ◽  
Harmonic Pollution ◽  
Point Of Common Coupling ◽  
Common Coupling ◽  
Load Types ◽  
Theoretical Results

In this article, a method that allows sharing responsibilities for the generation of harmonic currents between the utility and consumers powered by one point of common coupling (PCC) is addressed. For these purposes, mathematical modeling of the power supply system (PSS) with two consumers is carried out in order to introduce new indices using the simplest PSS structure as an example. Two indices are introduced that quantify the consumers’ contribution to the distortion of current and voltage at the PCC and that evaluate harmonic emission from the utility side. Experimental tests are carried out where both linear and nonlinear loads are considered, capacitive loads are taken into account, and harmonic distortions from the utility side are modeled to show the applicability of the indices in a wide range of load types. The experiments confirmed the theoretical results and illustrated that the quantitative assessment of the contributions is unambiguous. It suggests that the proposed criterion could be a reasonable basis for further tax policy on harmonic pollution for each consumer at the PCC and for the utility.

A New Compensation Control Strategy for Grid-connected Wind Turbine and Fuel Cell Inverters in a Microgrid

2017 ◽  
Vol 8 (1) ◽  
pp. 272 ◽  
Author(s):  
A. Naderipour ◽  
A. A. Mohd Zin ◽  
M. H. Habibuddin ◽  
M. Moradi ◽  
M. Miveh ◽  
...  
Keyword(s):  
Fuel Cell ◽  
Wind Turbine ◽  
Distributed Generation ◽  
Control Method ◽  
Harmonic Distortion ◽  
Synchronous Reference Frame ◽  
Wide Range ◽  
Point Of Common Coupling ◽  
Frame Method ◽  
Common Coupling

The use of a new control method for grid-connected inverters for reducing the output current harmonic distortion in a wide range of grid-connected distributed generation (DG) applications, including wind turbine (WT) and fuel cell (FC) inverters is proposed in this paper. The control method designed to eliminate main harmonics in a microgrid (MG) and between MG and point of common coupling (PCC) and responsible for the correction of the system unbalance. Another advantage of the proposed control method is that it can be easily adopted into the DG control system without the installation of extra hardware. The proposed control method is comprised of the synchronous reference frame method (SRF). Results from the proposed control method are provided to show the feasibility of the proposed approach.

scholarly journals Harmonics Compensation by Using a Multi-Modular H-Bridge-Based Multilevel Converter

Energies ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4698
Author(s):  
Raul Gregor ◽  
Julio Pacher ◽  
Alejandro Espinoza ◽  
Alfredo Renault ◽  
Leonardo Comparatore ◽  
...  
Keyword(s):  
Control System ◽  
Predictive Control ◽  
Multilevel Converter ◽  
Nonlinear Loads ◽  
Current Harmonics ◽  
Voltage Sensors ◽  
Power Filter ◽  
Point Of Common Coupling ◽  
Common Coupling ◽  
Grid Side

This paper presents an active power filter based on a seven-level cascade H-bridge where the main contribution is a control strategy that combines model-based predictive control, the voltage vectors of the converter output levels, the phase shift PWM technique, and suboptimal DC-link voltage control. The proposed scheme greatly simplified the overall control system, making it well suited to compensate the current harmonics distortion at the grid side, generated by nonlinear loads connected to the point of common coupling. In addition, the proposed method achieved a balancing of the capacitor voltages of the seven-level cascade H-bridge converter by using the minimum DC-link voltage sensors. This feature significantly reduced the control system complexity and provided a low computational burden. Experimental results confirmed the feasibility and effectiveness of the proposed controller.

A 28-Pulse AC-DC Converter Based SMPS for Telecom Power Supply

2010 ◽  
Vol 11 (4) ◽  
Author(s):  
R. Kalpana ◽  
G. Bhuvaneswari ◽  
Bhim Singh ◽  
Shikha Singh ◽  
Sanjay Gairola
Keyword(s):  
Power Quality ◽  
Power Factor ◽  
Power Supply ◽  
Simulated Performance ◽  
Harmonic Currents ◽  
Point Of Common Coupling ◽  
Common Coupling ◽  
Switched Mode Power Supply ◽  
Laboratory Prototype ◽  
Wide Operating

This paper presents a new 28-pulse ac-dc converter for enhancing the power quality at the point of common coupling, while feeding a medium capacity switched mode power supply (SMPS). It consists of two series connected 14-pulse ac-dc uncontrolled converters fed by seven phase-shifted ac voltages. The proposed converter is found capable of suppressing up to 27 harmonic currents in the ac mains. The power factor is also improved to near unity over a wide operating range of the SMPS. The design and analysis of the proposed ac-dc converter is carried-out in detail. A laboratory prototype of the autoconnected transformer based 28-pulse ac-dc converter is developed, and various tests have been conducted on it to validate the simulated performance of the proposed converter. Several experimental results are also included to show the effectiveness and robustness of the proposed converter.

scholarly journals Impact of Harmonic Currents of Nonlinear Loads on Power Quality of a Low Voltage Network–Review and Case Study

Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3665
Author(s):  
Łukasz Michalec ◽  
Michał Jasiński ◽  
Tomasz Sikorski ◽  
Zbigniew Leonowicz ◽  
Łukasz Jasiński ◽  
...  
Keyword(s):  
Power Quality ◽  
Low Voltage ◽  
Harmonic Distortion ◽  
Experimental Tests ◽  
Total Harmonic Distortion ◽  
Quality Analysis ◽  
Nonlinear Loads ◽  
Distortion Factor ◽  
Harmonic Currents

The paper presents a power-quality analysis in the utility low-voltage network focusing on harmonic currents’ pollution. Usually, to forecast the modern electrical and electronic devices’ contribution to increasing the current total harmonic distortion factor (THDI) and exceeding the regulation limit, analyses based on tests and models of individual devices are conducted. In this article, a composite approach was applied. The performance of harmonic currents produced by sets of devices commonly used in commercial and residential facilities’ nonlinear loads was investigated. The measurements were conducted with the class A PQ analyzer (FLUKE 435) and dedicated to the specialized PC software. The experimental tests show that the harmonic currents produced by multiple types of nonlinear loads tend to reduce the current total harmonic distortion factor (THDI). The changes of harmonic content caused by summation and/or cancellation effects in total current drawn from the grid by nonlinear loads should be a key factor in harmonic currents’ pollution study. Proper forecasting of the level of harmonic currents injected into the utility grid helps to maintain the quality of electricity at an appropriate level and reduce active power losses, which have a direct impact on the price of electricity generation.

scholarly journals Harmonics Mitigation Based on the Minimization of Non-Linearity Current in a Power System

Designs ◽  
2019 ◽  
Vol 3 (2) ◽  
pp. 29 ◽  
Author(s):  
Mohammed S. Almutairi ◽  
Sillas Hadjiloucas
Keyword(s):  
Power Systems ◽  
Power System ◽  
Harmonic Distortion ◽  
Nonlinear Loads ◽  
Loading Constraints ◽  
Harmonic Pollution ◽  
Point Of Common Coupling ◽  
Ieee Standards ◽  
Total Voltage ◽  
Practical Constraints

Harmonic issues in power systems are becoming an important topic for industrial customers and power suppliers alike due to their adverse effects in both consumer appliances as well as for utility suppliers. Consumers should seek to reduce harmonic pollution, regardless of voltage or current distortion already present in the network. This article suggests a new method for suppressing distortions by using the non-linearity current index (NLCI) to determine the shunt single-tuned passive filter (STPF) compensator value in non-sinusoidal power systems, with the objective of maintaining the power factor within desired limits. The objective of the proposed method is to minimize the nonlinear current of customer’s loads in the power system at the point of common coupling (PCC). Moreover, the proposed design takes into consideration other practical constraints for the total voltage and individual harmonic distortion limits, ensuring compliance with (Institute of Electrical and Electronics Engineers) IEEE 519-2014 guidelines, maintaining distortions at an acceptable level while also abiding by the capacitor loading constraints established in IEEE 18-2012. The performance of the optimally designed compensator is assessed using well documented IEEE standards based on numerical examples of nonlinear loads taken from previous publications.

scholarly journals A Proposed Harmonic Monitoring System for Large Power Users Considering Harmonic Limits

Energies ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 4507
Author(s):  
Rosalia Sinvula ◽  
Khaled Mohamed Abo-Al-Ez ◽  
Mohamed Tariq Kahn
Keyword(s):  
Monitoring System ◽  
Renewable Energy Sources ◽  
Electronic Devices ◽  
Harmonic Distortion ◽  
Large Power ◽  
High Penetration ◽  
Point Of Common Coupling ◽  
Common Coupling ◽  
Power Utilities ◽  
The Individual

Most power utilities within Southern Africa are faced with the challenges of harmonic distortion due to the high penetration of renewable energy sources (RES) and the use of electronic devices. There is an excessive total harmonic distortion (THD) measured at the point of common coupling (PCC). In this paper, a proposed harmonic monitoring system for large power users (LPUs) is developed. This proposed system considers harmonic limits of the individual and THD of the customers allowed injecting into the network, which should be part of the contractual electricity supply agreement (ESA). Hence, it will enable the monitoring of harmonic distortion to be smooth by determining whether the customer has passed or failed compliance for individual harmonic order and the THD of the voltage. The measurements of harmonic distortion are done using the Unipower power quality (PQ) analyzers that are connected at different points within the industrial network. Measurements of harmonic distortion of an industrial site are compared to the simulation results performed by DIgSILENT software to validate the proposed harmonic monitoring system. Based on the validation results, it is recommended that the ESA between the power utilities and the customers should consist of the harmonic limits.

scholarly journals Optimising the AR Engraved Structure on Light-Guide Facets for a Wide Range of Wavelengths

Optics ◽  
2020 ◽  
Vol 2 (1) ◽  
pp. 25-42
Author(s):  
Ioseph Gurwich ◽  
Yakov Greenberg ◽  
Kobi Harush ◽  
Yarden Tzabari
Keyword(s):  
Theoretical Analysis ◽  
Light Guide ◽  
Spectral Band ◽  
Angular Range ◽  
The Past ◽  
Input And Output ◽  
Wide Range ◽  
The Given ◽  
Theoretical Results ◽  
Shape And Size

The present study is aimed at designing anti-reflective (AR) engraving on the input–output surfaces of a rectangular light-guide. We estimate AR efficiency, by the transmittance level in the angular range, determined by the light-guide. Using nano-engraving, we achieve a uniform high transmission over a wide range of wavelengths. In the past, we used smoothed conical pins or indentations on the faces of light-guide crystal as the engraved structure. Here, we widen the class of pins under consideration, following the physical model developed in the previous paper. We analyze the smoothed pyramidal pins with different base shapes. The possible effect of randomization of the pins parameters is also examined. The results obtained demonstrate optimized engraved structure with parameters depending on the required spectral range and facet format. The predicted level of transmittance is close to 99%, and its flatness (estimated by the standard deviation) in the required wavelengths range is 0.2%. The theoretical analysis and numerical calculations indicate that the obtained results demonstrate the best transmission (reflection) we can expect for a facet with the given shape and size for the required spectral band. The approach is equally useful for any other form and of the facet. We also discuss a simple way of comparing experimental and theoretical results for a light-guide with the designed input and output features. In this study, as well as in our previous work, we restrict ourselves to rectangular facets. We also consider the limitations on maximal transmission produced by the size and shape of the light-guide facets. The theoretical analysis is performed for an infinite structure and serves as an upper bound on the transmittance for smaller-size apertures.

Effects of H2 Addition to CNG Blends on Cycle-to-Cycle and Cylinder-to-Cylinder Combustion Variation in an SI Engine

2012 ◽  
Author(s):  
Mirko Baratta ◽  
Stefano d’Ambrosio ◽  
Daniela Misul ◽  
Ezio Spessa
Keyword(s):  
Diagnostic Tool ◽  
Combustion Process ◽  
Experimental Tests ◽  
Test Point ◽  
Pollutant Emissions ◽  
Engine Operation ◽  
Pressure Transducers ◽  
Rate Analysis ◽  
Spark Plug ◽  
Wide Range

An experimental investigation and a burning-rate analysis have been performed on a production 1.4 liter CNG (compressed natural gas) engine fueled with methane-hydrogen blends. The engine features a pent-roof combustion chamber, four valves per cylinder and a centrally located spark plug. The experimental tests have been carried out in order to quantify the cycle-to-cycle and the cylinder-to-cylinder combustion variation. Therefore, the engine has been equipped with four dedicated piezoelectric pressure transducers placed on each cylinder and located by the spark plug. At each test point, in-cylinder pressure, fuel consumption, induced air mass flow rate, pressure and temperature at different locations on the engine intake and exhaust systems as well as ‘engine-out’ pollutant emissions have been measured. The signals correlated to the engine operation have been acquired by means of a National Instruments PXI-DAQ system and a home developed software. The acquired data have then been processed through a combustion diagnostic tool resulting from the integration of an original multizone thermodynamic model with a CAD procedure for the evaluation of the burned-gas front geometry. The diagnostic tool allows the burning velocities to be computed. The tests have been performed over a wide range of engine speeds, loads and relative air-fuel ratios (up to the lean operation). For stoichiometric operation, the addition of hydrogen to CNG has produced a bsfc reduction ranging between 2 to 7% and a bsTHC decrease up to the 40%. These benefits have appeared to be even higher for lean mixtures. Moreover, hydrogen has shown to significantly enhance the combustion process, thus leading to a sensibly lower cycle-to-cycle variability. As a matter of fact, hydrogen addition has generally resulted into extended operation up to RAFR = 1.8. Still, a discrepancy in the abovementioned conclusions was observed depending on the engine cylinder considered.

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