Conductor Diameter Research Articles

Study on the relationship between electric field perception and distance factor of direct current overhead line

Abstract The main reason for line collision accidents in offline construction is that construction personnel have an insufficient perception of distance. In the range of viewing angles, due to the lack of reference objects, people lack a correct judgment of the actual height of overhead lines. Voltage, as the most direct electrical volume, has always been a key indicator of electrical protection. In this paper, the feasibility of electrostatic induction is verified through the combination of electrostatic field simulation and experiment, and the influencing factors of electrostatic induction are studied. The results show that electrostatic induction is strongly related to the environmental angle, and the inductive voltage increases with the increase of the high voltage side, and the increased amplitude gradually increases. In addition, the induction distance and the shape of the receiving antenna have an impact on the effect of electrostatic induction. However, the induction distance has the greatest influence on the electrostatic induction effect, followed by the length and diameter of the induction conductor. The research of this paper plays a technical guiding role in the distance measurement of transmission lines based on electric fields.

Probe with a metallic bowl termination to determine the electric material parameters from variable thicknesses

This paper discusses a new approach to determining the material electric parameters (dielectric constant and dissipation factor) through a technique based on identical material variation thicknesses. The copper bowl controls the material thicknesses and allows quick and safe measurements to get to the electromagnetic material information. This approach assumes that the discontinuities generated at the probe and bowl are identical and removed through mathematical operations. The material under test (MUT) gap thickness doesn’t exceed one millimeter. Some formulations have been developed to determine the discontinuity condensers and both capacitors of each thickness. Two proposed developments have been given to extract the complex effective and relative permittivities. A mathematical formula has been proposed to ensure the transition from effective to intrinsic parameters, where the MUT thicknesses and the probe’s outer diameter of the inner conductor are considered. A de-embedding operation is necessary, and the method is suitable but not limited to low-k. The coaxial probe is flat terminated, and the experimental validation has been made in the frequency ranges 1 MHz—2.2 GHz for FR-4 HTG-175 and 1 MHz—0.8 GHz for Alumina 99.5%. All MUTs are 5.0×5.0 cm2, except their thicknesses. The suggested approach is straightforward in sample insertion, simple in data acquisition and implementation, and precise in the final parameters’ results.

Desain Motor Kapasitor Dua Fasa Simetris 1 kW

Single phase induction motors are one of the most frequently used types of motors because of their economical, sturdy, simple and easy maintenance advantages. One application is for electric vehicles. When single phase induction motors are applied to electric vehicles there are problems related to torque regulation based on vehicle operating conditions where when operating on light road conditions the torque produced by the motor remains high. In this research, a single-phase induction motor was made to have the same proportion of torque produced by the main coil and auxiliary coil or a 1kW 1000 rpm symmetrical two-phase induction motor. The type of winding applied to the stator is divided screws with the main and auxiliary coils each occupying 18 stator slots, 45 conductors per slots,, with a conductor diameter of 1.2 mm. As a phase shifter at start and operation so that they differ by 90°, a capacitance of 505.51 µF is used. As a result of the winding modification, the induction motor parameter values ​​for each stator winding are the same. So the starting torque of the main and auxiliary coils is 3.89 Nm and 3.88 Nm respectively and the nominal torque produced by the main and auxiliary coils is 4.28 Nm and 4.29 Nm respectively.

Computation of corona generated ionic current environment of unipolar UHVDC transmission lines using gas bimolecular collision theory

Corona on UHVDC transmission line conductors initiates corona power loss and the inevitable ionic current flow environment at ground level. To limit this substantial flow of ionic current at ground levels, it is necessary to establish an appropriate line design configuration, including the diameter of the line conductor and the height level above the ground. It is a tedious and expensive process to establish this appropriate line design solely based on experimental findings. Hence, the computational based numerical analysis with the support of final experimental validation aids in arriving at a safe and optimal transmission line design dimension configuration. Thus, the ionic current flow environment of UHVDC transmission lines may be characterized by ionized space charge density, ionic current flow, and electrical field distribution. To estimate this ionic current flow, it is necessary to estimate the ionized space charge density in the ionization region, which incorporates the solution of the Poisson's equation. It is intricate to solve Poisson's equation with known boundary conditions: as ionization process depends on the atmospheric parameters also. Multiple computational techniques are developed to estimate the corona generated ionic current environment under the HVDC lines by waiving these atmospheric parameter effects and claims the lack of computational accuracy. In this paper, the unipolar corona equation, usually called Poisson's equation was solved by estimating the space charge ion density using the concept of gas bimolecular collision theory. The gas bimolecular collision theory inculcates the procedure to estimate the collisional reaction rate constant between the gas molecules at given atmospheric temperature and pressure parameters. Therefore, this paper developed a unique equation solution for the estimation of transition of the ionic current magnitudes at known atmospheric temperature and pressure ambient conditions. This unique equation solution prevents the multiple actual testing procedures offers to obtain safe and optimal line design dimension configurations. Multiple experimental studies are carried out up to ± 900 kV to compare the computed results in the outdoor and indoor climatic conditions at the ultra-high voltage laboratory, CPRI. Also, the computed results are compared with the results published in the literature. Based on the comparison of results, the developed computational technique exactly matches the experimental results and claims improved accuracy compared to other computational techniques.

Circunstances affecting the protection against electrode potential rise (EPR)

In this paper the earthing resistance of substations with different earth electrode and soil structures is investigated by simulation studies with the use of CDEGS (Current Distribution, Electromagnetic Fields, Grounding and Soil Structure Analysis) software code. The paper presents the effect of grid geometry, soil characteristics, the effectiveness of the vertical earth rods and the conductor diameter.

Lateral bearing characteristics of subsea wellhead assembly in the hydrate trial production engineering

Conductor and suction anchor are the key equipment providing bearing capacity in the field of deep-water drilling or offshore engineering, which have the advantages of high operation efficiency and short construction period. In order to drill a horizontal well in the shallow hydrate reservoir in the deep water, the suction anchor wellhead assembly is employed to undertake the main vertical bearing capacity in the second round of hydrate trial production project, so as to reduce the conductor running depth and heighten the kick-off point position. However, the deformation law of the deep-water suction anchor wellhead assembly under the moving load of the riser is not clear, and it is necessary to understand the lateral bearing characteristics to guide the design of its structural scheme. Based on 3D solid finite element method, the solid finite element model of the suction anchor wellhead assembly is established. In the model, the seabed soil is divided into seven layers, the contact between the wellhead assembly and the soil is simulated, and the vertical load and bending moment are applied to the wellhead node to simulate the riser movement when working in the deep water. The lateral bearing stability of conventional wellhead assembly and suction anchor wellhead assembly under the influence of wellhead load is discussed. The analysis results show that the bending moment is the main factor affecting the lateral deformation of the wellhead string; the anti-bending performance from increasing the outer conductor diameter is better than that from increasing the conductor wall thickness; for the subsea wellhead, the suction anchor obviously improves the lateral bearing capacity and reduces the lateral deformation. The conduct of the suction anchor wellhead assembly still needs to be lowered to a certain depth that below the maximum disturbed depth to ensure the lateral bearing stability, Thus, a method for the minimum conductor running depth for the suction anchor wellhead assembly is developed. The field implementations show that compared with the first round of hydrate trial production project, the conductor running depth is increased by 9.42 m, and there is no risk of wellhead overturning during the trial production. The method for determining the minimum conductor running depth in this paper is feasible and will still play an important role in the subsequent hydrate exploration and development.

A novel computational technique to analyse the corona generated ionized field environment of EHV/UHV DC transmission lines

Abstact The corona-generated electromagnetic field environment under and nearer to the extra high dc potential conductors generates an ill health environment which causes serious electrical threats to living organisms present in the conductor corridor. The ionized electromagnetic field environment is characterizing with ionized ionic current flow and enhanced electric field perturbation at ground levels. The primary factors which affect the safe and economical design dimensions of high potential dc conductors are conductor diameter, altitude, applied potential and atmospheric parameters such as temperature, humidity, pressure, and aerosol pollution, etc. This remains a challenging task to design the HVDC transmission system at extended potential levels, as HVDC system employed for a large amount of power transfer barrier in the electrical system to meet inevitable power thrust. To obtain a safe and economical design configuration, multiple experimental design measurements are essential at various climatic seasons which incorporates the tedious process and significant economical expenditure. To obtain the safe and cost-effective design dimension configuration, computational-based numerical analysis with final experimental validation offers substantial support. Using various computational methodologies, many researchers have attempted to guide the critical line design proportions to establish a safe and economical electrical environment beneath the lines at ground levels. All these computational techniques are emphasizing the algorithm iterative-based complex solutions claim the lack of computational accuracy. Hence, this work aims to provide a unique computational technique to analyse the ionised electromagnetic field environment of a unipolar UHV dc transmission system using modelling of the physics of the corona discharge procedure in the active high electrostatic field zone. Modelling of the corona discharge includes the estimation of the amount of new ionized ions generated in the ionization region dynamically claims complex less equations offer a unique solution. To validate the accuracy of the proposed computational technique, multiple outdoor experimental measurements are carried out at HV/EHV/UHV potential applications and discussed. Also, the computed results are compared with the experimental findings, from the comparison outstanding computational accuracy was marked.

Research on nondestructive identification and location algorithm of cables with discontinuous conductor diameters based on broadband impedance spectrum

The number of cables in the distribution system is extremely huge, but there are some cables with thinner conductors in the middle section, which may threaten the safety of the system. At present, there is no effective detection method for such problems. Based on the broadband impedance spectrum, this paper proposes an algorithm to identify and locate the cables with discontinuous conductor diameters in the middle using the integral transformation with Chebyshev window. The simulation and experimental results show that the algorithm proposed in this paper can realize the identification and location of the conductor thinning cable in the middle section, and the location error is less than 0.76%.

Research on the AC Loss of Multi-strand Round Conductors

Conductors are very common in our life, such as high-voltage cables and all household appliances. The vast majority of conductors, especially home circuits, use alternating current. There will be so-called AC loss in AC circuits, which will limit our design and improvement of electrical appliances. In this paper, the AC loss in the charging conductor is influenced by skin effect and proximity effect. First of all, we will introduce these two effects. Both effects cause energy loss via induction current. Secondly, variables related to energy loss are pointed by using finite element analysis. After modelling and analysis, energy loss depends on frequency, loss increase with increasing frequency. Secondly, among the different arrangements of conductors, the arrangement of hexagons will be more energy-saving. Finally, the degree of energy loss is related to the conductor’s diameter. As the conductor’s diameter increases, the energy loss increases first and then decreases. In the end, energy loss relies on the size of frequency and the arrangement of conductors and the diameter of conductors

Development of Medical Sensor Systems in Pulmonology Based on Electrical Impedance Measurement.

In order to experimentally confirm the dependence of the bioelectrical impedance on the flow rate of charged aerosol particles and the composition of bronchial secretions in small airways, the electrical impedance of an aerosol of 0.9% NaCl solution in polyethylene tubes of various diameters was studied. The electrical impedance was also measured in cylindrical chambers of various diameters and volumes filled with a 0.9% NaCl solution or a gelatin solution. The studies were carried out at frequencies of alternating electric current from 20 Hz to 150 kHz. It was shown that the electrical current is not recorded in the absence of a flow of aerosol particles, and the impedance decreases with an increase in the flow velocity. The impedance modulus and the phase angle of the electrical impedance has an expressed dependence on the composition of the conductive medium, the impedance modulus increases in the gelatin solution medium, with a decrease in the diameter of the electric current conductor, and decreases with an increase in the frequency of the probing alternating current. The obtained results confirmed the hypothesis about the influence of the speed of salty aerosol particles flow and the composition of bronchial secretions on the results of measuring electrical impedance.

Wind fragility assessment and sensitivity analysis for a transmission tower-line system

Wind fragility is essential to performance-based wind engineering, risk, and resilience assessment for transmission towers. However, it has not been sufficiently studied due to the key issues in performance evaluation and uncertainty treatment for transmission towers. The performance of high-rise structures can be severely weakened by geometric imperfections, but these impacts have not been well addressed for transmission towers. Besides, the current uncertainty treatment only considers the tower itself although the transmission tower is part of an interconnected tower-line system that has complex interactions with wind environment. Therefore, this paper provides a systemic solution for geometric imperfections of transmission towers, where the users can clearly observe the effect of geometric imperfections on the capacity and failure positions of transmission towers. On this basis, a wind fragility framework that incorporates the uncertainties of each line component, wind environment, and aerodynamic parameters is proposed for transmission towers. Finally, sensitivity analysis was conducted to identify the significant uncertainty parameters for tower capacity and demand by sensitivity diagram. It is found that in addition to the uncertainties of the tower itself, the uncertainties of wind profile exponent, outer diameter and aerodynamic parameter of conductors have significant effects on the fragility of transmission towers.

Optimal design configuration of corona rings for 1200 KV bus post insulators

Estimation and regulation of the electric field stresses at ultra-high voltage levels are vital to achieve the reliable power system operation. Designing of the sustainable ultra-high potential equipment’s are the major challenge for the design engineers to satisfy the modified power demand scenario. The substation bus post insulator is the one of the key devices supports to achieve the sustainable and reliable power system operation. The severe problem in designing of the station post insulator at ultra-high potential ratings is its field stresses. To control these severe field stresses, significant electrodes like bus conductors, toroid rings, grading rings and corona rings are essential. The appropriate selection of these high potential electrode dimensions supports the optimal economic power system operation: failure reports the catastrophic behaviour of the station bus post insulators. Hence, the significant research knowledge on optimal size of high potential electrodes of substation bus post insulators at Extra and ultra-high potential levels is necessary before designing of these high voltage electrodes. Usually, it is a tedious process to attain the optimal design dimensions and its positions of the high potential electrodes in the actual field. Thus, the sophisticated numerical analysis-based simulation studies provide significant support to obtain the optimal size of high potential electrodes of bus post insulators at ultra- high potential ratings. Therefore, this paper aims to present the numerical based simulation design and its study of the high potential electrodes of the 1200 kV substation bus post insulator. Multiple design configurations of the electrodes like various corona ring, grading ring, bus conductor diameters and its positions are considered and compared to analyse the effect of the electrical stress, potential distribution variation of the 1200 kV bus post insulator. Therefore, from the simulation investigations, the optimal design data configuration of high potential electrodes for 1200 kV substation bus post insulator was suggested. Also, the high voltage electrode design configuration of proposed 1200 kV insulator followed by the one of the manufacturing industries is tested and compared.

Comprehensive Analysis of Influencing Factors of AC Copper Loss for High-Speed Permanent Magnet Machine with Round Copper Wire Windings

AC copper loss from stator winding is one of the main losses of the high-speed permanent magnet machines (HSPMMs) and directly affects the performance of the machines. AC copper losses are influenced by many factors, including the frequency, conductor diameter, temperature performance, etc. These factors cause the AC losses to increase significantly at high frequencies due to the skin effect and proximity effect. In this paper, a comprehensive analysis of the AC copper losses of HSPMMs with round copper wire windings is presented. Firstly, the structure and parameters of a 60 kW, 30,000 rpm high-speed permanent magnet machine are provided. Then, based on this parameter, a 2D-finite element model (2D-FEM) is established to obtain the AC copper loss. Through the eddy-current field analysis, the current density distribution of the stator winding and the variation trends of AC copper losses under different frequencies are observed. In addition, by comparing the winding current density distribution and the AC copper loss value under different conditions, the influencing factors of AC winding losses are comprehensively analyzed, including the frequency, conductor diameter, number of conductors per slot, notch height of the stator slot, and working temperature. Finally, four stator coil cases are manufactured, which have different conductor diameters and wire strands. The AC losses of the four cases at different frequencies are tested, and the theoretical results are verified by measuring the AC/DC loss ratios (kac) of different conductor cases at various frequencies.

Monitoring of Surgical Wounds with Purely Textile, Measuring Wound Pads – II. Detection of Bacterial Inflammation by Measurement of Wound Tissue Temperature

Aims: This study was executed to aquire basic knowledge on relations between design characteristics and the quality of measurements, as well as the optimization of the design of purely textile, measuring wound dressings for the detection of wound tissue warming as an indicator for (bacterial) inflammation. Background: The normal healing of surgical skin wounds may be disrupted by complications, by far the most common being post-operative bacterial infections. Objective: The temperature of the wound and its surroundings – the main indicative parameter for the onset of bacterial inflammation – can be determined and shown by means of functionalized, purely textile wound dressings with measuring capability when used as part of a measuring and assistance system. The textile sensors comprise insulated electrical wires stitched onto a textile backing designed as double meander, which is appropriate for the detection of temperature, moist, and rectangular transverse elongation (indicating inflammation, bleeding or seroma discharge, and tissue volume increase as a sign of haemorrhage (into the tissue) or seroma formation). Methods: Major design parameters are diameter of the electrical conductor (wire) / distance between an electrical conductor and the nearest (parallel) conductor / spacing of the embroidered seams (upper thread loops) along a conductor / number of meander loops, and length, width, and area of the double meander sensor array. Results: Skin temperature rises a few degree Celsius resulting in differences in ohmic resistance in the order of a few parts per thousand. The ohmic resistance of the electrical sensor wire as measurement for the temperature under the dressing solely depends on the length of the wire. Neither the spacing between the sections of wire nor the spacing of the upper thread has any detectable direct effect on the determination of the temperature. Conclusion: To improve measuring accuracy, sensor wires as thin as possible should be used for two reasons: (1) because their ohmic resistance is higher, simplifying measurement, and (2) because they can be stitched closer together in wound dressings, enabling a longer sensor wire to be used in the area of interest.

A robust and efficient method to geometrically calculate the minimum bit stick-out in a deepwater conductor jetting project

The length of the bit protruding from the running conductor assembly (i.e., bit stick-out), a key factor in deepwater drilling design, directly affects the efficiency of the injection process and the bearing safety of the conductor after installation. To improve the efficiency and safety of conductor installation, it is necessary to establish a reasonable theoretical model of the bit stick-out to provide a feasible scheme for field applications. In this study, geometric judgment criteria of the reasonable bit stick-out location are proposed that determine whether the diameter of the nozzle jet circle is smaller than that of the conductor. These judgment criteria are applied to obtain the reasonable position of the minimum bit stick-out for different diameters of conductors and tricone bits. According to these judgment criteria, we propose a mathematical model of the minimum bit stick-out during deepwater conductor jetting, which considers the influence of the heterogeneity in the nozzle space. Through theoretical analysis and experimental research, combined with on-site cases, the results indicate that if the diameter of the nozzle jet circle is larger than that of the conductor, the reasonable bit stick-out location occurs where the upper boundary of the nozzle jet beam is tangential to the inner boundary of the lower end of the conductor. Conversely, the reasonable bit stick-out location occurs where the jet beam originating from the nozzle can reach the intersection of the jet trajectory and the curved surface formed by the main and secondary cones of the cone bit at the bottom of the well. A numerical simulation study reveals that when the bit stick-out is greater than 150 mm, the hole can be enlarged during the jetting process, thus increasing the installation depth of the conductor and affecting the stability of the conductor. In addition, the models established in this work are applied in the field. In 12 wells, the average value of the calculated results is 114.76 mm, which is close to the lower limit of the interval. Overall, the research results provide a more accurate theoretical basis for bit stick-out design in deepwater conductor jetting projects. This study can maximize the jetting depth, considering that the size of the created hole optimally matches the casing size to achieve wellbore stability. In addition, the developed procedure based on the proposed mathematical model can be applied more conveniently to different combinations of conductor and bit sizes in the field.

Effect of Joule-Heating Treatment on the Microstructure and Physical Properties of 16-Stranded Compressed Copper Wires

Compressed wires are produced by cross-sectionally compressing stranded conductors, which results in a smaller conductor diameter. This also leads to a lower weight wire, because a thinner external insulated coating can be used, compared to the low-voltage wires typically used in automobiles. However, a post production heat treatment of the compressed wires is required because plastic deformation occurs during compression after drawing the wires. In this study, the work hardening of stranded compressed copper wires was controlled by Joule-heating, and the resulting changes in microstructure, mechanical, and electrical properties after various annealing voltages (0, 25, 27, 31, 35, and 39 V) were observed. The results confirmed that as the annealing voltage increased from 0 to 31 V, the anisotropic deformation texture with a <111> orientation as the main component was reduced, and micrograins were generated throughout the stranded wires via recrystallization. At an annealing voltage above 31 V, the grains grew to be more than twice as large as those before heat treatment. At an annealing voltage of 31 V these structural changes contribute to the elongation increase of the compressed wires to 28.34%, and an improvement in electrical resistance to 145.85 mΩ.

Influence of Equivalent Circuit Resistances on Operating Parameters on Three-Phase Induction Motors with Powers up to 50 kW

This work shows the results obtained from studying the influence of equivalent circuit resistances on three-phase induction motors. The stator resistance, rotor resistance, and iron losses resistance affect the different motor operating variables (output power, current, speed, power factor, starting ratios, and maximum torque). These influences have been quantified, paying particular attention to the losses affected and their impact on efficiency. The study carried out does not apply optimization techniques. It evaluates the different influences of the equivalent circuit’s different resistances on its operation by evaluating applicable constructive modifications concerning available motors. The work has been limited to three-phase induction motors up to 50 kW and low voltage, with the nominal powers of the selected motors being 0.25 kW, 1.5 kW, 7.5 kW, 22 kW, and 45 kW. The tools used to carry out the study are analyzing the equivalent circuit and the simulation of the electromagnetic structure using a finite-element program. The variations proposed in each resistance for all the motors studied is not purely theoretical, as it is based on applying feasible constructive modifications, appropriately analyzed and simulated. These modifications are the variation of the conductor diameter in the stator coils, the change of the section of the rotor cage, and the selection of different ferromagnetic steel types.

Partial Discharge yang Merusak Isolasi SF6 pada Gas Insulated Switchgear (GIS) Tiga Fasa Pengaruh Keberadaan Partikel Asing

This paper analyzes the effect of the presence of foreign particles on an equilateral arrangement of 3 phase gas insulated switchgear (GIS) insulation equipment. Gas Insulated Switchgear (GIS) that uses SF6 insulation, partial discharge will occur as the insulation ages and there are several other factors that affect the insulation. Partial Discharge needs to be detected to avoid failures that cause damage to equipment in theGIS. In this calculation, the electric field characteristics will be analyzed in 3-phase equilateral GIS by varying the location of the particles in the GIS tank. Particles are modeled to have a length of 5 mm and a thickness of 0.5 mm located in a 3 phase GIS equilateral arrangement with a tank diameter of 150 mm and a conductor diameter of 25 mm. The electric field calculations are reviewed at several points in the 3-phase equilateral GIS tank. The simulation and calculation of the electric field were calculated with FEM method software. The results of the calculations show that thereare differences in the characteristics of the electric field between normal GIS and GIS where foreign particles are present. The difference in these characteristics can be seen in the magnitude of the electric field, and the ratio of eccentricity from some point of view.

On Electric Field Distribution and Temperature Rise Effect of High Power VLF Antenna

When a high-power very low frequency (VLF) communication system is in operation, the end of the antenna is in an alternating strong electric field environment. Due to dielectric loss, abnormal temperature rise may occur at the end of the antenna. To solve the problem, analysis on the electric field distribution and temperature rising effect at the end of the antenna is first carried out in this paper. The factors that affect the electric field distribution and temperature rising, including the amplitude and frequency of the excitation voltage, the diameter of the antenna conductor and the material properties of the outer sheath of the antenna, are studied in detail. A novel approach to improve the electric field distribution and to suppress temperature rising is proposed by designing a dielectric loss eliminator, and the effectiveness of the designed device is verified by simulation.

Design and Optimization of a High-Speed Permanent Magnet Synchronous Machine for Gas Compressors

In this article, a high-speed permanent magnet synchronous machine (PMSM), which is rated at 15 kW and 120 krpm for a gas compressor, is designed and optimized. According to the design specifications, two design schemes of different rotor topologies are presented and compared by the finite element method (FEM) to determine the preliminary scheme of the original machine. The performance of the original machine is obtained by FEM. Meanwhile, the losses of the original machine are analyzed and calculated for optimization. Especially, the conductor diameter of the winding is selected to reduce the copper loss of the machine. Finally, in order to reduce wind friction loss and increase power density, the dimensions of the stator core and the thickness of the permanent magnet (PM) are optimized. Compared with the original model, the wind friction loss is reduced by 17.2%, and the power density is increased by 6.64% in the optimized machine.