scholarly journals Non-Intrusive Identification of Load Patterns in Smart Homes Using Percentage Total Harmonic Distortion

Energies ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4628 ◽  
Author(s):  
Hari Prasad Devarapalli ◽  
V. S. S. Siva Sarma Dhanikonda ◽  
Sitarama Brahmam Gunturi
Keyword(s):  
Light Emitting Diode ◽  
Harmonic Distortion ◽  
Electricity Consumption ◽  
Side Lobe ◽  
Vital Role ◽  
Total Harmonic Distortion ◽  
Distribution Grid ◽  
Digital Controllers ◽  
Nonlinear Loads ◽  
Harmonic Pollution

Demand Response (DR) plays a vital role in a smart grid, helping consumers plan their usage patterns and optimize electricity consumption and also reduce harmonic pollution in a distribution grid without compromising on their needs. The first step of DR is the disaggregation of loads and identifying them individually. The literature suggests that this is accomplished through electric features. Present-day households are using modern power electronic-based nonlinear loads such as LED (Light Emitting Diode) lamps, electronic regulators and digital controllers to reduce the electricity consumption. Furthermore, usage of SMPS (Switched-Mode Power Supply) for computing and mobile phone chargers is increasing in every home. These nonlinear loads, while reducing electricity consumption, also introduce harmonic pollution into the distribution grid. This article presents a deterministic approach to the non-intrusive identification of load patterns using percentage Total Harmonic Distortion (THD) for DR management from a Power Quality perspective. The percentage THD of various combinations of loads is estimated by enhanced dual-spectrum line interpolated FFT (Fast Fourier Transform) with a four-term minimal side-lobe window using a LabVIEW-based hardware setup in real time. The results demonstrate that percentage THD identifies a different combination of loads effectively and advocates alternate load combinations for recommending to the consumer to reduce harmonic pollution in the distribution grid.

Analysis on Harmonics Caused by Connecting Electric Vehicle Chargers with Power Network

2013 ◽  
Vol 724-725 ◽  
pp. 1393-1397
Author(s):  
Xiang Zhen Li ◽  
Guang Ming Hu ◽  
Peng Xin Hou ◽  
Yu Bo Fan ◽  
Chun Lin Guo
Keyword(s):  
Electric Vehicle ◽  
Harmonic Distortion ◽  
Total Harmonic Distortion ◽  
Power Network ◽  
Nonlinear Loads ◽  
Harmonic Current ◽  
Current Ratio ◽  
Harmonic Pollution ◽  
Charging Stations ◽  
The Impact

As a class of nonlinear loads in the power system, electric vehicle chargers will produce a certain harmonic pollution for the grid. Before the construction of charging stations, it is necessary for electric vehicle charger (station) connected to the grid to simulate and predict harmonics. The models of single charger and charge station are built separately in order to simulate and analysis the impact of a single and multiple chargers on power quality. The factors of the harmonic current ratio (HRI) and the current total harmonic distortion (THDI) varied with the charging power and the number of the chargers are discussed and analyzed. The generation mechanism of harmonic counteraction and interaction between the chargers are analyzed. The simulation results show that: because of the impedance of the system and the transformer, the harmonic current ratio (HRI) and the current total harmonic distortion (THDI) both increase firstly to some extent and subsequently decrease gently with the increase of the number of the chargers in the same power charging. This phenomenon has nothing to do with the harmonic counteraction and how that happen is discussed and analysis in this paper. And the phenomenon of harmonics interaction and counteraction occurs with the increase of the number of the chargers in different power charging, and the current total harmonic distortion (THDI) declines and tends to maintain a relatively stable value.

scholarly journals Characterization of nonlinear loads in power distribution grid

2016 ◽  
Vol 29 (2) ◽  
pp. 159-175 ◽  
Author(s):  
Miona Andrejevic-Stosovic ◽  
Marko Dimitrijevic ◽  
Slobodan Bojanic ◽  
Octavio Nieto-Taladriz ◽  
Vanco Litovski
Keyword(s):  
Power Factor ◽  
Power Distribution ◽  
Harmonic Distortion ◽  
Electric Circuit ◽  
Quality Parameters ◽  
Distribution Grid ◽  
Nonlinear Loads ◽  
Highly Nonlinear ◽  
Wide Range

Electronic devices are complex circuits, consisting of analog, switching, and digital subsystems that require direct current (DC) for polarization. Since they are connected to the mains delivering alternating current (AC), however, AC-to-DC converters are to be introduced between the mains and the electronics to be fed. A converter is an electric circuit containing several subsystems, the most important being the switch-mode power supply, drawing power from the mains in pulses hence it is highly nonlinear. That happens, in reduced amplitude, even when the electronics to be fed is switched off. The process of AC-to-DC conversion is not restricted to feeding electronic equipment only. It is more and more frequently encountered in modern smart-grid facilities giving rise to the importance of the studies referred hereafter. The converter can be studied (theoretically or by measurements) as two-port network with reactive and nonlinear port-impedances. Characterization is performed after determining the port electrical quantities which are voltages and currents. Based on these data power and power quality parameters - power factor and total harmonic distortion- may be extracted. When nonlinear loads are present, one should introduce new ways of thinking into the considerations due to the existence of harmonics and related power components. In that way the power factor can be generalized to total or true power factor where the apparent power, involved in its calculations, includes all harmonic components. After introducing a wide range of definitions used in contemporary literature, here we describe our measurement set-up both as hardware and a software solution. The results reported unequivocally confirm the importance of the subject of characterization of small nonlinear loads to the grid having in mind their number which is rising without saturation seen in the near and even far future.

scholarly journals Power Quality Improvement by Reduction of Total Harmonic Distortion (THD) using PWM Inverter

2020 ◽  
Vol 9 (2) ◽  
pp. 1641-1643
Keyword(s):  
Quality Improvement ◽  
Power Quality ◽  
Harmonic Distortion ◽  
Total Harmonic Distortion ◽  
Nonlinear Loads ◽  
Pwm Inverter ◽  
System A ◽  
Power Quality Improvement ◽  
Simulation Results ◽  
And Performance

In this paper, a PWM inverter is proposed for improvement of power quality i.e., reduction of total harmonic distortion (THD). The power quality problems reduce the lifetime and performance of equipments. The proposed system reduces the THD which is generated from the nonlinear loads. Because presence of harmonics leads to problems like overheating, failure of insulation etc. Here the simulation results of the proposed system is studied using MATLAB SIMULINK. Using the system, a lower THD is achieved which shows the effectiveness of the system.

scholarly journals Research of the Negative Influence of Dimmed LED Luminaires in Context of Smart Installations

2021 ◽  
Vol 13 (17) ◽  
pp. 9753
Author(s):  
Peter Drgona ◽  
Peter Durana ◽  
Tibor Betko
Keyword(s):  
Power Factor ◽  
Light Emitting Diode ◽  
Harmonic Distortion ◽  
Negative Influence ◽  
Total Harmonic Distortion ◽  
Correction Function ◽  
Inrush Current ◽  
Inrush Currents ◽  
Negative Impacts ◽  
Led Drivers

This article deals with the investigation of the negative impacts of dimmed public, industrial and office LED (light emitting diode) light installations. This approach is required due to the uncertain design of LED ballasts, while manufacturers do not implement the required PFC (power factor correction) function. Therefore, the focus is on a brief description of the principles of negative influences such as: low power factor, high inrush current and high total harmonic distortion based on direct confrontation with actual standards (IESC EN, NEMA, ENERGY STAR). Further, the behavior of LED drivers is explained under nominal load and dimmed up to critical level. Presented findings confirm issues reported by users from larger installations where LED fittings are dimmed over a certain level. The article includes recommendations for consumers and producers of LED fittings about main issues from the scientific and user points of view. Presented facts conclude on the necessity of studying the marginal operating state of LED fittings aiming at THD (total harmonic distortion), PF (real power factor) and inrush currents.

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.

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