Distortion Factor Research Articles

Method to identify the phase structures of high entropy alloys with modified lattice distortion enthalpy

Severe lattice distortion is one of important characteristics of high entropy alloys (HEAs) and exercises considerable influence over phase structures, and atomic volume V is thought to be the key factor for lattice distortion. In the present work, the calculation of V was modified by taking the stacking density effects into consideration, and the calculation of lattice distortion enthalpy (∆HLD) caused by elastic lattice distortion for HEAs was optimized accordingly. With this method, two phase structure formation rules were proposed: valence electron concentration(VEC)−∆HLD rule for crystal structure of solid solution and chemical enthalpy(∆Hchem)−∆HLD rule for phase composition. The prediction effect of these two rules were verified by analyzing 100 existing HEAs, and the intrinsic effect of lattice elastic distortion on the phase formation of HEAs were discussed. The results of the research would be helpful in the composition design of HEAs.

Seven levels fuzzy rule-based controller for modified shunt active line conditioner

ABSTRACT This paper presents a seven levels inverter (MLI) used as 3Φ Modified Shunt Active Line Conditioner (MSALC) providing features of low harmonic distortion (low THD) and low Harmonic Current Ratio Factor (HCRF), reduced switching losses, suppressing harmonic currents, compensation of reactive power, enhancement of power factor, balancing load current under unbalanced non-linear load and distorted voltage conditions. It employs Self Tuning Filters (STF) for ideal (reference) current generation. Fuzzy Rule-Based (FRB) current controller generates switching patterns or sequence for Electrical potential source inverter. MATLAB fuzzy logic trainer toolbox is used for stimulating the proposed system. The effectiveness of the presented MSALC is desirable to suppress harmonics which is proved from the simulation results validated by experimental prototype hardware using the THD and HCRF values obtained which is not yet reported in other Shunt Active Line Conditioner (SALC) for various types of loads under both steady state and dynamic load conditions.

Poverty as a factor of distortion of reproductive exchange

Poverty as a factor of distortion of reproductive exchange

Theoretical and Numerical Study on Electrical Resistivity Measurement of Cylindrical Rock Core Samples Using Perimeter Electrodes

The estimation of hydraulic and mechanical properties of bedrock is important for the evaluation of energy-related structures, including high-level nuclear waste repositories, hydraulic fracturing wells, and gas-hydrate production wells. The hydraulic conductivity and stress–strain curves of rocks are conventionally measured through laboratory tests on cylindrical samples. Both ASTM standards for hydraulic conductivity and compressive strength involve the use of the planar bases of a cylindrical sample. Hence, an alternative test method is required for the simultaneous measurement of hydraulic conductivity and stress–strain curves. This study proposes a novel electrical resistivity estimation method using two perimeter electrodes for the estimation of hydraulic properties. The theoretical background for the perimeter electrode setup is derived and the COMSOL MultiPhysics® finite element numerical simulation tool is employed to verify the derived theoretical equation. The accuracy of the numerical simulation tool is first validated by simulating the ASTM standard testing method for electrical resistivity. The electrical resistance values derived from the theoretical equation and numerical simulation are compared for different electrical resistivity and electrode radius. The assumed equidistant, circular equipotential surface results in a theoretical lower bound for the measured electrical resistance in the cylindrical specimen. The introduction of a phenomenological distortion factor to correct for the theoretical equipotential surface results in a good fit with the numerical simulation results. The effects of electrode length and equivalent strap electrodes were investigated to assess the applicability of the suggested method for laboratory testing. Consequently, this study presents an effective alternative theoretical assessment method for the lower bound electrical resistivity of cylindrical rock core samples under confining conditions when the installation of base electrodes is infeasible.

English

Recently the use of sensitive electronic devices has increased, and the quality of energy has become an important factor in electrical power systems, where disturbances occurring in the network (harmonics, swell, voltage sag, etc.) affect consumers and lead to technical-economic damages. One of the most prominent solutions to address energy quality problems is the UPQC (Unified Power Quality Conditioner). In this paper, the unified power quality conditioner used to improve the electrical power quality in the distribution networks was discussed, where the Park transformations are used to obtain the required reference signals, and also the use of adaptive hysteresis band to generate the electronic switch pulses in both serial and shunt switches, where the pulse width is determined by dependence on fuzzy logic. The studied system was validated by simulating different distortion cases and comparing the results when using the Sinusoidal Pulse Width Modulation (SPWM) to control the two switches. The results showed improvement in the electrical power quality through the use of an adaptive hysteresis band controller, and that appeared by reducing the total distortion factor (THD%), which resulted in improving the shape of both the voltage and current waveforms.

Analysis of energy quality in power supply systems with grid-connected solar power plants

The article presents an analysis of the quality of voltage at a consumer of electricity in power supply systems with a network solar power plant connected in parallel to the centralized network. The legislative base of the Russian Federation, regulating the construction and operation of grid solar power plants, requirements for the quality of energy in a centralized grid have been studied. The block diagram of the operating experimental solar power plant is presented. On the basis of this station, experimental studies of the influence of the operation of a solar power plant on the quality of energy at the consumer have been carried out. This study was carried out using a Fluke 345 power quality analyzer. The authors analyzed the experimentally obtained data on voltage changes and harmonic distortions at the consumer in two series of experiments (with a solar power plant in operation and with a solar power plant disconnected). On the basis of the analysis, conclusions were drawn about the reduction of peak voltage deviations at the consumer and a decrease in the total harmonic distortion factor when the solar power plant is operating. The relationship between voltage and harmonic distortion is described mathematically. Based on the results of the studies, conclusions were drawn about improving the quality of energy for an agricultural consumer when supplied with electricity from a grid solar power plant in parallel with a centralized grid.

Impact of the Wind Turbine on the Parameters of the Electricity Supply to an Agricultural Farm

Wind power plants are an increasingly common source of electricity located in rural areas. As a result of the high variability of wind power, and thus the generated power, these sources should be classified as unstable sources. In this paper, the authors attempted to determine the impact of wind turbine operation on the parameters of electricity supplied to farms located near the source. As a result of the conducted field tests, variability courses of the basic parameters describing the supply voltage were obtained. The influence of power plant variability on the values of voltage, frequency, and voltage distortion factor was determined. To estimate the capacity of the transmission lines, the reactive power produced in the power plant and its effect on the value of the power factor were determined. The conducted research and analysis showed that the wind power plant significantly influences voltage fluctuations in its immediate vicinity (the maximum value registered was close to 2%, while the value required by law was 2.5%). Although all the recorded values are within limits specified by the current regulations (e.g., the THD value is four times lower than the required value), wind turbines may cause incorrect operation of loads connected nearby. This applies mainly to cases where consumers sensitive to voltage fluctuations are installed in the direct vicinity of the power plant.

Hybrid Three-Phase Rectifiers with Active Power Factor Correction: A Systematic Review

The hybrid three-phase rectifiers (HTR) consist of parallel associations of two rectifiers (rectifier 1 and rectifier 2), each one of them with a distinct operation, while the sum of their input currents forms a sinusoidal or multilevel waveform. In general, rectifier 1 is a GRAETZ (full bridge) (can be combined with a BOOST converter) and rectifier 2 is combined with a DC-DC converter. In this HTR contest, this paper is intended to answer some important questions about those hybrid rectifiers. To obtain the correct answers, the study is conducted as an analysis of a systematic literature review. Thus, a search was carried out in the databases, mostly IEEE and IET, and 34 papers were selected as the best corresponding to the HTR theme. It is observed that the preferred form of power distribution in unidirectional hybrid three-phase rectifiers (UHTR) is 55%Po (rectifier 1) and 45%Po (rectifier 2). For the bidirectional hybrid three-phase rectifiers (BHTR), rectifier 1 preferably takes 90% of Po and 10% of Po is processed by rectifier 2. It is also observed that the UHTR that employ the single-ended primary-inductor converter (SEPIC) or VIENNA converter topologies in rectifier 2 can present sinusoidal input currents with low total harmonic distortion (THD) and high Power Factor (PF), even successfully complying with the international standards. The same can be said about the rectifier that employs a pulse-width (PWM) converter of BOOST topology in rectifier 2. In short, the HTR are interesting because they allow using the GRAETZ full bridge topology in rectifier 1, thus taking advantage of its characteristics, being simple, robust, and reliable. At the same time, the advantages of rectifier 2, i.e., high PF and low THD, are well used. In addition, this article also points out the future direction of research that is still unexplored in the literature, thus giving opportunities for future innovation.

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

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.

IMPROVED PERFORMANCE OF PHOTOVOLTAIC BASED EMBEDDED DUAL POWER SOURCE SL-QUASI Z SOURCE INVERTER FOR IM DRIVE

This paper presents the performance of PV-based embedded dual power source of SL quasi Z source inverter. The SL quasi Z source inverter with an embedded PV source and a dual power source (DPS) is injected into the system. The DPS helps the system to operate at an equilibrium state and stabilizes the entire system during PV power fluctuations. The design of the proposed system is carried out in MATLAB/Simulink environment. The control strategy with the PI controller is adopted. ESLQ Z source inverter with voltage boost method is employed with basic SPWM methodology will be suitable for IM drive applications. The system has the merit of a low inrush current that will protect and increase the life of switching devices. Finally, the study and simulation setup is validated by proving their good operating features. The proposed work is trustworthy that minimizes the total distortion factor, start-up inrush current with improved performance. Keywords: Photo voltaic (PV), embedded dual power SL quasi Z source inverter, Induction motor drive (IM), PI controller.

LCD-based method for evaluating modulation transfer function of optical lenses with poorly corrected distortion

Modulation transfer function (MTF) evaluation in the imaging of the optical lenses with poorly corrected geometric distortion involves sampling region of interest (ROI) images that are affected by geometric distortion, reducing its accuracy. A based liquid-crystal-device MTF (LMTF) method is proposed for this purpose by evaluating MTF of the medical rigid endoscope. This method establishes a mathematical model of geometric distortion and analyzes two sampling ROI image manners in MTF evaluation. Compared with the distortion factor (DF) manner, the distortion correction manner relaxes the value of the DF to twice the maximum non-distortion value, extends the sampling ROI image to twice the size, reduces the average RRMSE value to 6%, and improves average accuracy on MTF by 1.2%. The experimental results provide good agreement with the theoretical prediction. Therefore, the proposed LMTF method can be referential for the other optical lenses with poorly corrected distortion.

Octahedral tilting dominated phase transition in compressed double perovskite Ba2SmBiO6

The comprehension of structural behaviors in double perovskites is crucial for their functional optimization, especially when applying external regulations. Here, to inquire about potential structures with better magnetic performance, high-pressure phase transformation in double perovskite Ba2SmBiO6 was first investigated up to 50 GPa via in situ high-pressure x-ray diffraction and Raman spectroscopy. A pressure-induced phase transition from cubic Fm-3m to orthorhombic Pnma is discovered at 4.8 GPa, accompanied by the splitting of the diffraction peaks. Above 19.8 GPa, the new phase becomes distorted as shown by the peak recombination and broadening. The variation of Raman spectra also confirms the formation and distortion of the high-pressure phase during compression, through the evolution of Bi–O stretching, Bi–O bending, octahedral rotation, and Ba-sites translation modes. The analysis of tilt angles and distortion factor evinced that the octahedral BiO6 tilting is the key factor for the phase transition occurrence. Based on the Mulliken populations analyses, the Bi–O bonds undergo a covalent-ionic-antibonding transition across the phase transition under compression. Our exploration of the phase transition mechanism guides the modulation of the magnetic and electronic properties under extreme conditions.

Switching strategies for a multi-level inverter

The article examines the methods of switching the stages of a multi-level inverter in order to reduce the harmonic factor of the output voltage of the inverter. These methods use pulse-width modulation for switching, which is obtained by comparing a reference sinusoidal signal and a sequence of triangular pulses. The article describes the algorithms for obtaining the control sequence of pulses and simulates each of the strategies. The dependence of the nonlinear distortion factor on the frequency of the carrier wave for different switching strategies is obtained based on the simulation results. The influence of the LPF on the quality of the output voltage of the inverter is also investigated. In addition, an experimental study of a six-level inverter was carried out. The waveforms and spectrograms of the inverter were obtained using the Fluke 434-II electrical energy analyzer. The harmonics of the output voltage, which are distinguished by power from the entire spectrum, were identified.

The optimization of the filter compensating devices parameters choice at the enterprises of agro-industrial complex

The optimization function of the filter compensating device has been determined, the purpose of which was the possibility of the harmonic distortion factor minimizing, the arguments of which are the power of individual filters. To analyze and compare the efficiency of the filter compensating device, quality indicators measurements of the electrical energy at an agricultural machine-building plant were made. Using the developed methodology for the filter-compensating devices optimal parameters calculating in the Mathcad software environment, the parameters selection and determination of two options of filter-compensating devices were made. According to the calculations, it was found that for the object under study, the most optimal, effective and economical device is a filter compensating one with a narrow-band filter tuned to the 5th harmonic and a wide-band filter of the 3rd order tuned to the 7th harmonic.

Plate Structural Analysis Based on a Double Interpolation Element with Arbitrary Meshing

Abstract This paper presents the plate structural analysis based on the finite element method (FEM) using a double interpolation element with arbitrary meshing. This element used in this research is related to the first-order shear deformation theory (FSDT) and the double interpolation procedure. The first stage of the procedure is the same with the standard FEM for the quadrilateral element, but the averaged nodal gradients must be computed for the second stage of this interpolation. Shape functions established by the double interpolation procedure exhibit more continuous nodal gradients and higher-order polynomial contrast compared to the standard FEM when analysing the same mesh. Note that the total degrees of freedom (DOFs) do not increase in this procedure, and the trial solution and its derivatives are continuous across inter-element boundaries. Besides, with controlling distortion factors, the interior nodes of a plate domain are derived from a set of regular nodes. Four practical examples with good results and small errors are considered in this study for showing excellent efficiency for this element. Last but not least, this element allows us to implement the procedure in an existing FEM computer code as well as can be used for nonlinear analysis in the near future.

ВПЛИВ ФІЛЬТРА В КАНАЛІ КЕРУВАННЯ КОНТУРОМ СТАБІЛІЗАЦІЇ НАПРУГИ НАКОПИЧУВАЛЬНОГО КОНДЕНСАТОРА НА ДИНАМІКУ ТРИФАЗНОГО ПАРАЛЕЛЬНОГО АКТИВНОГО ФІЛЬТРА

The object of research is a three-phase shunt active power filter, which consists of a semiconductor voltage inverter on fully controllable switches, capacitive storage, and an RL-link. The carried-out decomposition of the research object according to the rate of motion of the dynamic system makes it possible to divide this dynamic system into two subsystems, interconnected by control. The role and influence of the communication subsystem between the voltage stabilization circuit on the storage capacitor of the three-phase shunt active power filter and the circuits for the formation of the compensation current, which is injected by this filter into the distributed power supply network, is considered. The presence of a non-linear load in this network is a source of distortion of the parameters of electrical energy. The formation of the compensation current by the forced introduction of the first order sliding modes along some sliding surfaces was carried out. The two-dimensional sliding surface is a linear combination of the components of the two-dimensional error vectors of the compensation current and the first derivative of the error of this current. The introduced communication subsystem makes it possible to reduce the influence of the disturbance in the form of harmonic components of the rectified voltage on the parameters of the compensating current. The influence of the dynamic characteristics of a communication subsystem with filtering properties on the performance indicators of a parallel active filter and the current distortion factor in the power supply network to which this filter is connected was analyzed. To confirm the theoretical assumptions, a simulation model was built and the results of digital modeling were analyzed. Comparison of different types of filters as a communication subsystem according to the criteria of the duration of the transient process and the harmonic distortion in the current that consumed from the network was carried out. References 26, figures 4, tables 3.

Evaluation of central tendency measures in relation to the parameters of contact network feeders controlled by relay protection

The paper considers the importance of possible input values of standby stages of remote protection of contact network feeders from the point of view of their influence on the reliability of protection. The measures of the central tendency of parameters controlled by relay protection of contact network feeders were evaluated based on the theory of statistics, using the example of the Trans-Baikal Railway for 2018-2019. In total, 14 parameters were measured according to GOST 32144-2013. Electric power. Electromagnetic compatibility of technical facilities. Standards for the quality of electric energy in general-purpose power supply systems, in 2020 on the feeder of the contact network of the Sokhondo traction substation of the Trans-Baikal Railway against 88965290 obtained values, which made it possible to select significant values from all possible parameters on the basis of mathematical analysis. Statistical data on the following parameters were considered and analyzed: effective voltage value, effective current, peak voltage amplitude factor, peak current amplitude factor, harmonic voltage distortion factor, harmonic current distortion factor, phase shift factor, load resistance, angle between the first voltage harmonic on substation buses and feeder current. The reasonable selection of significant parameters proposed by the authors allows improving the operation of standby stages of remote protections of contact system feeders in heavy traffic conditions and increasing their selectivity.

Gaseous Ionization Dependence of Surface Charge Pattern on Epoxy Insulator With Complex Surface Profile Under DC Voltage

Surface charge accumulation on epoxy insulator installed in gas-insulated transmission line (GIL) and gas-insulated switchgear (GIS) has been recognized as a crucial factor for electric field distortion that results in the reduction of surface flashover voltage. This article reports on the gaseous ionization dependence of the charge accumulation pattern on a real-size epoxy insulator with multiarc surface profile by using various gas atmospheres. A coaxial electrode system was designed to investigate the charging behavior under dc voltages of -10, -20, and -30 kV. The insulator and electrodes were placed in a metal-enclosed test chamber, which was filled with 0.1 MPa air or 0.4 MPa SF <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">6</sub> /N <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> mixture to estimate the influence of the gas atmosphere on the charge accumulation behavior by a Kelvin-type probe. The accumulation mechanism and the electric field distortion induced by the charges were demonstrated based on numerical simulation. The results indicated that positive charges were accumulated in the shape of speckle on insulator surface in air, whereas both positive and negative charges were accumulated in SF <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">6</sub> /N <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> mixture and positive charge speckles appeared in SF <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">6</sub> /N <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> mixture only when the voltage raised up to -30 kV. It is considered that the charge accumulation behavior is determined by the competition result among the bulk, the gas and the surface conductions. As compared with the case in air, gaseous ionization in SF <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">6</sub> /N <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> mixture is more difficult to occur, which leads to the obvious difference in the charge accumulation pattern.

Study of Arabic Translation of “ Her Eyes” According to Bremen’s Deconstructive Method

Translation criticism, based on the patterns of cognitive translations, is a criterion to describe the translation function in the target language by preserving literature and understanding the meaning of the source language. The validity of the translation of the novel will also be measured and represented with meticulous awareness of the shortcomings and its positive features according to the principles of translation evaluation models. Antone Breman, whose basis of his translational viewpoint is based on the source text, explains the twelve deforming tendencies between the source, target language named “deconstructive method” or “distortion factors”. According to this theory, when the number of changing trends in the translation process is more significant, the translator has distorted the original text more. In this study, we want to consider the perspective of Bremen’s deconstructive tendencies with respect to the alien text and foreign, Arabic translation called “Aynaha” by Ahmad Musa of “Her Eyes” written by Bozorg Alavi. The main focus of this research is to review the dominant trends in text change by translator mentioning to citing the evidence and proposed translation. Findings of the study confirm six trends of twelve Bremen deconstructive tendencies, and it claims that the translator, according to his own taste, has made changes in translation, and he was not loyal to the source text.

A Genetic-Based Hybrid Algorithm Harmonic Minimization Method for Cascaded Multilevel Inverters with ANFIS Implementation

Selective harmonic elimination pulse-width modulation (SHEPWM) is a widely adopted method to eliminate harmonics in multilevel inverters, yet solving harmonic amplitude equations is both time consuming and not accurate. This method is applied here for a 7-level cascaded multilevel inverter (CMLI) with erroneous DC sources. To meet the seven harmonic amplitude equations, two notches are applied with the use of higher switching frequency than nominal. These notches can be placed in six different positions in the voltage wave, and each was assessed in a separate manner. In order to solve the equations, a hybrid algorithm composed of genetic algorithm (GA) and Newton–Raphson (N-R) algorithm is applied to achieve faster convergence and maintain the accuracy of stochastic methods. At each step of the modulation index (M), different positions for the notches are compared based on the distortion factor (DF2%) benchmark, and the position with lowest DF2% is selected to train an artificial neural fuzzy interface system (ANFIS). ANFIS will receive the DC sources’ voltages together with required M and will produce one output; thus, eight ANFISs are applied to produce seven firing angles, and the remaining one is to determine which one of the notches’ positions should be used. Software simulations and experimental results confirm the validity of this proposed method. The proposed method achieves THD 8.45% when M is equal to 0.8 and is capable of effectively eliminating all harmonics up to the 19th order.