Three-phase Line Research Articles

Quantum Dot Self-Assembly Deposition in Physically Confined Microscale Space by Using an Inkjet Printing Technique.

Inkjet printing technique is susceptible to form coffer-ring patterns and inhomogeneous films owing to the evaporation and its accompanying hydrodynamics of microscale quantum dot droplet. Pioneer efforts are usually confined to two-dimensional flat substrates and inks with mixed solvents/additives. Herein we demonstrate that physically confined space offers an additional parameter in tailoring such processes of droplets and the following quantum-dot self-assembly deposition, without extra modification of quantum dots or solvent chemistry. Owing to the boundary of physically confined space, two three-phase border lines in both the bottom center (horizontal direction) and the barrier of the bank substrate (vertical direction) arise, inducing dual capillary flows and Marangoni backflows. The evaporation, fluid flow, and film-forming process in physically confined space are studied by introducing well-prepared single-solvent quantum dots inks. The systematical analysis offers valuable instructions including ink preparation, surface modification, and postprocessing evaporation technique for inkjet-printed patterning applications, especially for pixelated display, polychrome patterning, and sensor array.

The study of water wettability on solid surfaces by molecular dynamics simulation

The wetting of nanodroplets on solid surfaces was studied by molecular dynamics simulations. Through investigation of the contact angle of nanodroplets with different sizes, a relatively stable and accurate contact angle was obtained for a droplet radius of larger than 43 Å (1 Å = 10−10 m). The contact angles for droplets at different levels of solid-liquid forces were quantitatively evaluated. The results show that there is an excellent linear correlation between them in the angle range of 28° to 167°. Under a strong solid-liquid force, thin liquid film expansion in the three-phase line was found in nanometer-level simulations. The thin film spreading range increased with increasing solid-liquid force.

Wave Propagation on High Voltage Power Lines.(Dept.E)

Travelling waves in power systems is of importance in solving problems relating to power-line carrier communication, protection of very long lines, energiestion of unloaded lines and calculation of recovery voltages on cir-cuit breakers under fault conditions. This paper presents comprehensive analyses for wave propagation on single-phase and on three-phase overhead power transmission lines. Using modal quantities, the wave equation are solved. Natural modes are illustrated to clarify the propagation of carrier signals on single circuit lines as well as on double circuit lines. Different transmission line configurations are considered. The effect of power line transposition on carrier modes is also included.

Mathematical models of the new remote transformer current transducers

New designs of remote transformer current converters (RTCC) have been developed in this article. It is shown that an increase in sensitivity is achieved due to the implementation of the magnetic circuit in the form of a multiturn core with a common measuring winding, and the use of three identical RTCC installed to measure currents of all three phases with connected measuring windings according to open triangle circuit expands the functionality of device due to the simultaneous measurement of currents in three phases and unbalanced currents in a three-phase circuit. Generalized mathematical models of new RCTT have been developed taking into account the influence of magnetic fields of currents of neighboring buses for the most general case of their location in space in relation to the buses of a three-phase line. It is shown that for RTCC type TVM-P, in which the parallel rods are made in the form of a multi-turn core with a corresponding measuring winding, in order to reduce the effect on the readings of the current transducer installed to measure the current in phases A, the number of turns of the measuring winding located at a distance from of buses B and C, the multiturn core of the U-shaped magnetic circuit should be selected large in relation to the measuring winding placed on the multiturn core closest to the buses B and C.

Motor Current Signature Analysis-based Non-invasive Recognition of Mixed Eccentricity Fault in Line Start Permanent Magnet Synchronous Motor

— In this study, a cost-effective and non-invasive detection strategy is proposed for three-phase line start permanent magnet synchronous motor (LSPMSM) under mixed eccentricity fault using motor current signature analysis. In this respect, theory of air gap magnetic field in eccentric LSPMSM is presented. The detection strategy is examined through modeling and experimental studies. Two-dimensional time stepping finite element method is employed to calculate the motor parameters. Effects of mechanical load and fault severity on eccentric LSPMSM are also investigated. Different fault-related components are scrutinized and the most effective features are identified for this new type of electrical motor. The results indicate that amplitudes of fault-related components at rotor frequency are precise for early detection of mixed eccentricity in LSPMSM. Finally, an efficient frequency pattern as well as detection criterion is specified.

ОСОБЛИВОСТІ ЕКРАНУВАННЯ МАГНІТНОГО ПОЛЯ ПІДЗЕМНОЇ ТРИФАЗНОЇ КАБЕЛЬНОЇ ЛІНІЇ ЗА ДОПОМОГОЮ НАСИПНОГО КОМПОЗИЦІЙНОГО ҐРУНТУ З МАГНІТНИМИ ВЛАСТИВОСТЯМИ

The computations of the magnetic field generated by high-voltage (330 kV) underground power cable line with special fill-up soil having different dimensions (bulk) are carried out by the two- and three-dimensional computer models. The supplementary soil above the cables is the composite material with effective magnetic properties and serves as a magnetic shield. The computer results obtained by 2D and 3D models are compared. The efficiency of magnetic field shielding depending on the magnetic permeability, width, and height of the fill-up soil is studied. As revealed, there is the optimal small soil height for the best magnetic field mitigation on the top of the ground directly over the cable line. In addition, the width of the magnetic soil has an appreciable effect on shielding efficiency. The shielding of underground single-circuit three-phase power cable lines is efficient only when using the magnetic fill-up soil (or ordinary external screen made of magnetic materials) with enough small height. References 14, figures 7.

Mathematical Study on Traveling Waves Phenomena on Three Phase Transmission Lines – Part I: Fault-Launched Waves

A mathematical study on the traveling waves (TWs) propagation phenomena on three-phase power lines under fault conditions is presented in this article. This article is divided into two parts, and this part focuses on the analytical development of expressions that describe fault-launched TWs as functions of line and fault parameters. From the obtained mathematical representation of TWs launched by faults, TW-based applications can be designed in a more reliable way, justifying the relevance of the presented study.

Shape Deviation of Surface Structures Produced by WaveShape (Structuring by Laser Remelting) on Ti6Al4V and a Method for Deviation Reduction.

Laser structuring by remelting (WaveShape) is a manufacturing process for metal surfaces in which structures are generated without material removal. The structuring principle is based on the controlled motion of the three-phase line in the area of the solidification front. The contour of the solidification front is imprinted into the remelting track during the continuous solidification process. Typically, harmonic surface structures in the form of sinusoidal oscillations are generated by means of WaveShape with virtually no material loss. However, a significant shape deviation is often observed over a wide range of process parameters. In this study, it was found that much of the shape deviation is concentrated at a spatial wavelength equal to half the spatial wavelength used for structuring. Therefore, an approach to reduce the shape deviations was specifically investigated by superimposing a compensation signal on the harmonic structuring signal. In this approach, a compensation signal with half the spatial wavelength was varied in phase and amplitude and superimposed on the structuring signal. Amplitude and phase shift of the compensation signal were further investigated for selected laser beam diameters and spatial wavelengths. This demonstrated that a shape deviation of harmonic surface structures on titanium alloy Ti6Al4V could be reduced by up to 91% by means of an adapted compensation signal.

Thermal Effect of Single Loop Shield on High-Voltage Cable Line Capacity

The paper deals with a single-loop shield with an asymmetric magnetic coupling used for a magnetic field mitigation of a high-voltage three-phase cable line. The goal is to evaluate a thermal effect of this shield on a cable line capacity. To calculate the flat cable line capacity in the nonshielded case, we use a standard IEC 60287. To achieve the goal we carry out a numerical simulation of the thermal field when the shield is installed. Wherein, we deal with two specific sections. One is a long section with the shield being distant from the cable line. The other is a relatively short section where the shield is located near the power cables. The thermal field is applied for a long section in a two-dimensional formulation, and a three-dimensional formulation is used for the short section. Hence, we have obtained the dependences of the maximum temperature of the power cables on parameters of the shield and its location height above the cable line. The most significant allowable cross-sections of the shield cable and their location height have been determined, when the thermal effect of the shield does not decrease the cable line capacity. These results have ensured the maximum cable line capacity while shielding. The shield temperature is shown to exceed the allowable level in the short section. To reduce it the thermal backfill has been used. We recommend the values of its thermal resistivity to be used for different parameters of the single-loop shield.

Dependency of Contact Angles on Three-Phase Contact Line: A Review

The wetted area of a sessile droplet on a practical substrate is limited by the three-phase contact line and characterized by contact angle, contact radius and drop height. Although, contact angles of droplets have been studied for more than two hundred years, there are still some unanswered questions. In the last two decades, it was experimentally proven that the advancing and receding contact angles, and the contact angle hysteresis of rough and chemically heterogeneous surfaces, are determined by interactions of the liquid and the solid at the three-phase contact line alone, and the interfacial area within the contact perimeter is irrelevant. However, confusion and misunderstanding still exist in this field regarding the relationship between contact angle and surface roughness and chemical heterogeneity. An extensive review was published on the debate for the dependence of apparent contact angles on drop contact area or the three-phase contact line in 2014. Following this old review, several new articles were published on the same subject. This article presents a review of the novel articles (mostly published after 2014 to present) on the dependency of contact angles on the three-phase contact line, after a short summary is given for this long-lasting debate. Recently, some improvements have been made; for example, a relationship of the apparent contact angle with the properties of the three-phase line was obtained by replacing the solid–vapor interfacial tension term, γSV, with a string tension term containing the edge energy, γSLV, and curvature of the triple contact line, km, terms. In addition, a novel Gibbsian thermodynamics composite system was developed for a liquid drop resting on a heterogeneous multiphase and also on a homogeneous rough solid substrate at equilibrium conditions, and this approach led to the same conclusions given above. Moreover, some publications on the line energy concept along the three-phase contact line, and on the “modified” Cassie equations were also examined in this review.

Reduced graphene oxide-based calcium alginate hydrogel as highly efficient solar steam generation membrane for desalination

Solar-driven evaporation has been considered as one of the potential methods for desalination and sewage treatment. However, optical concentrators and complex multi-component systems are essential in advanced technologies, resulting in low efficiency and high cost. Here, we synthesize a reduced graphene oxide-based porous calcium alginate (CA-rGO) hydrogel which exhibits good performance in light absorption. More than 90% of the light in the whole spectrum can be absorbed. Meanwhile, the water vapor escapes from the CA-rGO film extremely fast. The water evaporation rate is 1.47 kg·m−2·h−1, corresponding to the efficiency 77% under only 1 kW·m−2 irradiation. The high evaporation efficiency is attributed to the distinctive structure of the film, which contains inherent porous structure of hydrogel enabling rapid water transport throughout the film, and the concave water surfaces formed in the hydrophilic pores provide a large surface area for evaporation. Hydrophobic rGO divides the evaporation surface and provides a longer three-phase evaporation line. The test on multiple cyclic radiation shows that the material has good stability. The CA-rGO hydrogel may have promising application as a membrane for solar steam generation in desalination and sewage treatment.

Вибір системи живлення низьковольтних однофазних електроприймачів повітряних ліній напругою 220/380 В

Two-phase three-wire and single-phase two-wire branches from main three-phase lines are integral components of three-phase four-wire systems. Therefore, the aim of this work is to choose the optimal power supply system for single-phase electrical receivers depending on their power and branch length. The comparison of single-, two- and three-phase power supply systems of single-phase electric receivers is carried out and analytical expressions are obtained to determine power losses, phase voltage loss and wire cross section for allowable voltage loss at the same total active load power and its equal distribution between phases. Based on the obtained expressions, the total power losses, voltage loss in phase and neutral wires for different power supply systems are analyzed. In the transition from a three-phase four-wire power supply system of single-phase electric receivers to a single-phase two-wire or two-phase three-wire system with the same total load power and equal load phases with wire cross sections selected for allowable voltage loss, power loss and phase voltage with a corresponding decrease in their active resistance. It is shown that in some cases the use of single-phase and two-phase branches saves conductive materials in comparison with the three-phase linear branch, the cross section of which is inflated due to the need to ensure the condition of mechanical strength. The dependences of the limiting length of three-phase and single-phase overhead insulated lines, which corresponds to the allowable voltage loss, on the active load power are calculated. It is shown that the limiting length of three-phase linear branches significantly exceeds the limiting lengths of single-phase and two-phase branches at the same load power. The optimal version of the power supply system should be selected on the basis of technical and economic calculation depending on the load capacity, line length and allowable voltage loss.

Analysis of rotor asymmetry fault in three-phase line start permanent magnet synchronous motor

This article proposed a detection scheme for three-phase Line start permanent magnet synchronous motor (LSPMSM) under different levels of static eccentricity fault. Finite element method is used to simulate the healthy and faulty LSPMSM with different percentages of static eccentricity. An accurate laboratory test experiment is performed to evaluate the proposed index. Effects of loading condition on LSPMSM are also investigated. The fault related signatures in the stator current are identified and an effective index for LSPMSM is proposed. The simulation and experimental results indicate that the low frequency components are an effective index for detection of the static eccentricity in LSPMSM.

Arduino-Based Three-Phase Inverter Using Power MOSFET for Application in Microgrid Systems

Rapid depletion of fossil fuel reserves, and concerns over climate change have encouraged power generation from sustainable energy based microgrids. And to address the necessity of three-phase inverters in microgrid systems or sustainable-powered households, an Arduino-based three-phase inverter using MOSFET is designed, which converts DC into three-phase AC power. The designed system generates 223V square signals at each phase from a 12V battery through switching of three stages of power MOSFETs using pulse width modulation (PWM) signals at their gates from an Arduino Uno. Each stage of power MOSFETs consists of six transistors making it eighteen in total, which are used to perform the inversion process separately for each three single-phase connections. The system is programmed using an Arduino Uno to generate PWM signals and to keep 120 degrees phase displacement among each phase. Three step-up transformers are coupled at the outputs of MOSFET stages for amplification. The system generates 386.25V of voltage for the three-phase line delivering 0.58A of current using a 60W incandescent bulb at each phase as a load. The design and simulation of the electronic circuit are done by Proteus, and the programming codes are written using Arduino IDE. The designed system is practically contrasted and verified.

АНАЛІЗ МАТЕМАТИЧНИХ МОДЕЛЕЙ ЛІНІЙ ЕЛЕКТРОПЕРЕДАЧІ

This paper investigates a mathematical model of one elements of the power supply system - power transmission lines. The type of models depends on the initial simplifications, which in turn are determined by the complexity of the physics of processes. The task of improving the accuracy of modeling of emergency processes in the power system is due to the significant complexity of modern power systems and their equipment, high-speed relay protection, automation of emergency management and the introduction of higher-speed switching equipment. One of the reasons for a significant number of serious emergencies in the system is the lack of complete and reliable information for modeling modes in the design and operation of power systems. The development of a mathematical model of a three-phase power line, which provides adequate reflection of both normal and emergency processes, is relevant. The advanced mathematical model of power transmission lines allows to investigate various operational modes of electric networks. The improved mathematical model of the power transmission line reflects all the features of physical processes at state modes and transient process and provides sufficient accuracy of the results. The type of mathematical model of power transmission lines depends on the accepted simplifications, depending on the task of research. The purpose of this work is to analyze the mathematical model of the power transmission line to study the modes of operation of the power supply system, with the possibility of its application to take into account all the design features of overhead and cable power lines. The mathematical model of the power line for the study of the modes of operation of the power supply system is analyzed. It is used to take into account the design features of overhead and cable power lines, skin effect.

On the Influence of Dielectric-Coated Conductors on the Performance of Three-Phase Compact Distribution Lines Against Indirect Lightning Strikes

This article presents an investigation on the performance of a three-phase compact distribution line against nearby lightning strikes. It is shown that neglecting the insulating layer that surrounds the phase conductors as usually done in this type of study does not significantly change voltages induced from phase to ground, but can have some effect on voltages induced between phase and messenger, which are the ones that effectively stress the insulation. However, the observed differences are strongly minimized if the usual practice of grounding messenger and neutral in regular intervals of less than 200 m is considered. This is confirmed by a Monte-Carlo-type study that shows that the failure rate of the line is not affected by the inclusion of the insulating layer that surrounds the phase conductors in practical conditions.

Disk-Ring Deposition in Drying a Sessile Nanofluid Droplet with Enhanced Marangoni Effect and Particle Surface Adsorption.

The present study is to explore the central particle deposition from drying a sessile nanofluid droplet experimentally and theoretically. Normally, a pinned colloidal droplet dries into a coffee-ring pattern as a result of moving the particles to a three-phase line by the radial direction capillary flow. However, the strong evaporation can generate the nonuniform temperature at the evaporating droplet interface and the droplet periphery temperature is higher than that close to the droplet centerline. The induced Marangoni flow would reversibly transport the particles at the periphery toward the centerline. We have thus designed the experiments to increase the droplet evaporation rate in vacuum conditions and accordingly to enhance the Marangoni effect. We have observed distinguishable disk deposition inside the outer coffee ring. A three-dimensional diffusion-limited cluster-cluster aggregation Monte Carlo model has been developed to simulate the deposition process. With modeling the Marangoni effect, particle adsorption at the liquid-air interface and particle aggregation behaviors, the formation of the disk pattern inside a coffee ring has been simulated. The qualitative agreement has been found in the comparison of local deposition distribution between the related experiment and simulation.

Evaluation of Influence to Electromagnetic Environment on Outside of Building by PLC System using Three-wire Three-phase Power Line

Evaluation of Influence to Electromagnetic Environment on Outside of Building by PLC System using Three-wire Three-phase Power Line

Solvent-Mediated Forces between Ellipsoidal Nanoparticles Adsorbed at Liquid-Vapor Interfaces.

Classical capillary theory predicts that a non-neutrally wetting ellipsoidal particle adsorbed at a liquid–vapor interface will deform the interface. The deformation gives rise to anisotropic capillary forces of a quadrupolar nature that induce strong directionality in the particle interactions. Here, we investigate the interactions between nanoparticles with characteristic lengths of 1–5 nm. We show that the near-field interactions are dominated by solvent-mediated forces, which arise from the fluid packing between the nanoparticles and direct nanoparticle–nanoparticle interactions. The solvent-mediated forces are two orders of magnitude larger than the estimated capillary force. We find that interacting ellipsoidal nanoparticles adsorbed at the liquid–vapor interface have a larger repulsion in the depletion region than the nanoparticles submerged in a dense bulk phase and argue that this is because of a negative line tension associated with the three-phase line.

Traveling-Wave-Based Fault Location Method for Hybrid Distribution Network Mixed with Three-Phase and Phase to Phase Supply Lines

In China, a hybrid distribution network mixed with three-phase main lines and phase to phase supply lines can be found in many MV distribution networks due to lower cost of using two lines from three-phase main lines as well as lower cost of phase to phase transformer. For such a hybrid distribution network it is a challenge for traditional fault location techniques. This paper presents a traveling wave fault location method based on double-terminal measurement techniques. The proposed method analyses the traveling wave propagation mechanism of both aerial mode and zero mode components for a fault. The method then determines which mode component is used for the fault location according to fault types. The method has been developed and assessed on a typical distribution network using ATP power network simulation tool. The tests were conducted under various fault scenarios. The results show that zero mode component is more effective for a fault on the phase of three-phase main lines which is not linked to the phase to phase supply lines. However for a phase-to-phase fault, aerial mode component is more effective. For the remaining fault types, either aerial or zero mode component can be used.