Arrangement Of Conductors Research Articles

A novel method based on PSO algorithm and ANN for magnetic flux density estimation near overhead transmission lines

Abstract This paper introduces a novel method that leverages artificial neural networks to estimate magnetic flux density in the proximity of overhead transmission lines. The proposed method utilizes an artificial neural network to estimate the parameters of a mathematical model that describes the magnetic flux density distribution along the lateral profile for various configurations of overhead transmission lines. The training target data is acquired using the particle swarm optimization algorithm. A performance comparison between the proposed method and the Biot-Savart law-based method is conducted using an extensive test dataset. The resulting coefficient of determination and mean square error values demonstrate the successful application of the proposed method for a range of different spatial arrangements of phase conductors. Furthermore, the performance of the proposed method is thoroughly assessed on multiple test cases. The practical relevance of the proposed method is highlighted by contrasting its results with the field measurements obtained in the proximity of a 400 kV overhead transmission line.

Electromagnetic and thermal performance study on a canted stack of REBCO tapes

Abstract Due to the critical current limitation of a single REBCO tape, stacking methods are generally employed to increase the current carrying capacity in practical high-temperature superconducting (HTS) applications. However, the overall critical current is strongly dependent on the self-magnetic field, which is influenced by the geometrical arrangement of conductors in the stack. Due to the brittle ceramic property, REBCO tapes are conventionally bent along the thickness side of the tape. However, the difference in bending radii of the outer and inner tape surfaces in the stack may lead to fracture deformation, thereby limiting the stacking number of REBCO tapes. To balance the stacking number with the bending issue, canted stack is proposed as a variant of normal stack for REBCO tapes. As a potential HTS intermediate component, it is imperative to conduct a comprehensive study on electromagnetic and thermal performance of canted stack. The unique geometrical arrangement of canted stack introduces new factors that affect critical current and transport AC loss. This paper concludes the special influencing factors of canted stack, including canted angle, stacking number, tape width, and spatial structure. The metal interleaving method is introduced for spatial distribution changing and thermal stability. Furthermore, orthogonal analysis is performed to elucidate the comprehensive correlation among these multiple factors. This study provides insights into the overall critical current and transport AC loss for different combinations of canted stack and establishes a predicting function for critical current to support the structural design of canted stack. Based on the specific case study, the improvement effect of canted stack is confirmed by both experiments and simulations.

Optimization of conductors arrangement in slot for alternating current winding losses reduction

PurposeThe purpose of this study is to evaluate and minimize the losses of alternating current (AC) in the winding of electrical machines. AC winding losses are frequently disregarded at low frequencies, but they become a significant concern at high frequencies. This is the situation where applications require a high speed. The most significant applications in this category are electrical propulsion and drive systems.Design/methodology/approachAn analytical model is used to predict the AC losses in the winding of electrical machines. The process involves dividing the slot into separate layers and then calculating the AC loss factor for each layer. The model aims to calculate AC losses for two different winding arrangements involving circular conductors. This application focuses on the stator winding of a permanent magnet synchronous motor that is specifically designed for electric vehicles. The model is integrated into an optimization process that makes use of the genetic algorithm method to minimize AC losses resulting from the arrangement of conductors within the slot.FindingsThis study and its findings demonstrate that the arrangement of the conductors within the slot has a comparable effect on the AC losses in the winding as the machine's geometric and physical properties. The effectiveness of electrical machines depends heavily on optimizing the arrangement of conductors in the slot to minimize AC winding losses.Originality/valueThe proposed strategy seeks to minimize AC winding losses in high-speed electric machines by providing a cost-effective and precise solution to improve energy efficiency.

Assessment of Lightning Current Injection Tests in Replicating the In-flight Current Distribution on Aircraft

Lightning is one of the natural threats to an aircraft. Laboratory tests are usually limited to aircraft component levels and scaled prototypes. For small aircraft, sometimes the whole aircraft could be subjected to the lightning current specified in the relevant standards. Lightning current injection tests are carried out with standard components A to D. This is in anticipation of producing expected levels of fields and current values during a lightning strike. However, generating a current waveform with a rise time and magnitude the same as component A is very difficult in practice. Further, standards specify a return conductor (RC) arrangement for testing. Fields generated due to RC current can affect the current and field distribution. Hence, the emulated current and field in such tests could differ from that in an actual strike. The present work evaluates the current distribution for different lightning current waveforms suggested in standards and that realised in the laboratory. Also, the effect of the return cage on the current/field distribution is studied. The current and voltage distribution on aircraft skin is obtained by employing the impedance network method. A discretised model of Standard Dynamics Model (SDM) aircraft is employed for the present study. It is found that the surface current distribution on aircraft during a laboratory test can differ from that during the actual strike. Owing to the inductance of the aircraft, the rise time of the lightning current realised in the laboratory could be slow compared to that specified in standards; hence, it could also affect the current distribution on aircraft. This work is intended to provide insight into the inherent limitations of laboratory-level testing, which could be helpful for designers.

Design and Assessment of Track Structures in High-Frequency Planar Inductors

This paper investigates the effect of different designs and arrangements of conductors on the operational parameters of a planar inductor. Accordingly, it is suggested that there is no one-size-fits-all design that can achieve all desired parameters in every application, and the best design should be determined by the needs of the application. In order to have a comprehensive study, four different structures are considered and compared. Numerous design parameters such as track width, track length, location of the conductors between the central limb and the lateral limb, and number of transposition points among subtracks for both air-core and ferrite-core inductors are considered. Each structure is evaluated according to AC resistance, RAC/RDC, and inductance. Measurement results reveal that it is critical to take into account all three characteristics when deciding the suitable structure for the conductors. Studies are carried out based on measurement results for experimental prototypes in the frequency range of 10 Hz–1 MHz, and a set of guidelines is provided with regard to the design of planar inductors to achieve desired characteristics.

Novel functional and fail-safe knitted heating structures via the dedicated serial-parallel circuits for heating design approach

This paper presents the simulation-based development of a novel knitted design of textile heating structures based on dedicated serial-parallel circuits for heating (DSPCh) using silver-plated yarns processed via knitting technology. The DSPCh approach features dedicated and spatially bounded sub-circuits, ensuring even heat distribution and resilience against circuit failures in smart textiles with heating functionality. The study finds that the conductor arrangement and knitting pattern significantly affect the heating performance. DSPCh structures achieve even more heat distribution than serial and parallel circuit designs. Due to its binding, the developed basic pattern based on the right–left knit is less electrically conductive than that based on the right–right knit. Results show that DSPCh structures exhibit a favorable heat level and uniform heat distribution suitable for wearable textiles close to the body. The comparison with other circuit designs demonstrates higher temperatures of maximum 132°C and temperature differences up to 100 K, making DSPCh structures suitable for functional underwear. In addition, the experiments reveal that the heating performance is minimally degraded after standard machine-washing and care protocols. The investigations demonstrate that the DSPCh structures are suitable for actively heatable functional underwear, and simulation tools can aid in predicting temperatures and heat distribution for various textile designs.

Modeling Power Flows and Electromagnetic Fields Induced by Compact Overhead Lines Feeding Traction Substations of Mainline Railroads

The ongoing re-equipment of electric power systems is based on the use of smart grid technologies. Among the key tasks that are solved on this basis are increasing the capacity of power transmission lines, reducing losses, and improving power quality. To address these issues, one can use compact power transmission lines. Such lines are notable for their complex split-phase designs and close together placement of current-conducting parts, so as to keep the distance to a permissible minimum, which is achieved by the use of insulating spacers. This article reports the results of computer-aided simulations performed for a standard railroad power supply system, the traction substations of which were connected to 220 kV networks through compact overhead lines (COHLs). The purpose of the study was to calculate the values of quantitative metrics that measure power quality and energy efficiency as well as electromagnetic safety. Modeling was performed in the three-phase reference frame with the use of techniques and algorithms implemented in the Fazonord software package. We considered a power supply system with 25 kV overhead contact systems. It was assumed that the external network used three different designs of COHLs: with coaxial, linear, and sector-shaped arrangements of conductors. Based on the results obtained, we concluded that (1) when using COHLs, the voltages on bow collectors of electric rolling stock were stabilized and did not exceed permissible limits; (2) losses in the traction network were reduced; and (3) the parameters of power quality and electromagnetic safety conditions in external power supply systems of railroads were improved, if judged in terms of electric and magnetic field strengths. Out of the eight types of COHLs considered, compact lines with the three-segment and concentric arrangement of conductors had the best performance, and the use of COHLs with the vertical arrangement of conductors made it possible to reduce electric field strengths. However, the designs of such transmission lines are quite complex and entail higher construction costs.

Study on the Interference Law of AC Transmission Lines on the Cathodic Protection Potential of Long-Distance Transmission Pipelines

Through inductive coupling, AC transmission lines can generate large amounts of voltage to buried oil and gas pipelines in areas with common corridors, posing a threat to the cathodic protection effect of pipelines. Therefore, this paper investigates the effect of AC transmission lines on the cathodic protection of long-distance pipelines through inductive coupling. COMSOL Multiphysics finite element simulation software is used to calculate the distribution of cathodic protection potential of long-distance pipelines under different voltage levels, parallel spacing, conductor-to-ground height, conductor arrangement and pipeline burial depth for normal operation of AC transmission lines. Comparison and analysis of the AC transmission line on the pipeline cathodic protection potential interference law is conducted. The results show that: 1. AC transmission lines cause serious electromagnetic interference with the pipeline cathodic protection system, which will cause the pipeline cathodic protection potential to shift out of the effective protection area. 2. The maximum value of the induced voltage of the pipeline will appear at the two ends of the pipeline, and the induced voltage of the pipeline in the middle position is 0. 3. The shift of the pipeline cathodic protection potential increases with the increase of voltage level and decreases with the increase of parallel spacing, conductor height and burial depth. The pipeline cathodic protection potential shift is highest when the wires are arranged horizontally and lowest when they are arranged in an umbrella shape.

Conductor Arrangement and Phase Sequence Optimization Scheme for 500 kV Four-Circuit Transmission Lines on Same Tower

Conductor Arrangement and Phase Sequence Optimization Scheme for 500 kV Four-Circuit Transmission Lines on Same Tower

GA-CSM based optimized clearances for the reduction of occupational exposure in EHV substation

• Multi-objective GA-CSM based algorithm is proposed, for the first time, to identify the optimal ground clearances of EHV substation conductors for adherence to the ICNIRP guidelines. • CSM models are developed as per the actual layout of the substation and E-fields are computed in view of occupational exposure. • Modified ground clearances are obtained for the existing conductor arrangement and for the best topology among the transposed topologies. • Novel substation layout with reduced inner bay heights is proposed. The magnitude of the electric field (E-field) in a 765 kV substation is reduced by altering the conductor clearances in view of the occupational exposure limits. Multi-objective genetic algorithm (GA) along with the charge simulation method (CSM) is utilized in arriving at the optimal clearances of the substation conductors. An EHV substation is modeled with the dimensions and the clearances as in the actual layout of a substation. The E-field results obtained using the finite-line based modeling and infinite-line based modeling of conductors, are compared in terms of the model accuracy and the computational time. The advantages of using the infinite-line based CSM model in view of the occupational exposure is detailed. With the proposed GA-CSM routine, the maximum value of the E-field in the substation is reduced to 10 kV/m (from the existing value of 13 kV/m). The proposed method is used with the existing topology and the best possible transposed topology to obtain the modified layouts. A novel EHV substation layout with different ground clearances for the inner bays and the outer bays is presented. The GA-CSM routine proposed in this work is applicable to any EHV substation with the multiple conductor arrangements.

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

Power Flow Modeling of Multi-Circuit Transmission Lines

To reduce the allocation of land for the construction of electric power facilities, it is possible to leverage multi-circuit overhead transmission lines (MCTLs), in which the conductors of several circuits of different voltage classes are placed on the same tower. The unique features of the arrangement of conductors on MCTL towers cause unequal inductances and capacitances of different phases. In addition, there are significant mutual electromagnetic influences on the line circuits. To account for these factors, it is advisable to model the power flow of electric power systems equipped with MCTLs using the phase frame of reference. On the basis of such models, it is possible to determine the power flows while taking into account lateral and transverse asymmetries and to analyze electromagnetic safety conditions along the routes of multi-circuit transmission lines. We proposed a technique for modeling power flows and electromagnetic fields of multi-circuit power transmission lines, in which conductors of several circuits of different voltage classes are placed on the same tower. The methodology is based on the application of phase coordinates, which are the most natural description of three-phase power systems. The method is versatile enough to be applied to solving the specified problems for MCTLs of different designs. The article presents the results of research aimed at developing a method for modeling MCTL power flows. The results of modeling power flows of an electrical network including a three-circuit power transmission line are presented. The practical use of the models developed by the authors will make it possible to make well-grounded choices regarding the options for the use of multi-circuit power lines.

Mechanism of Thrust–Power Ratio Improvement Using Plasma Actuator with Discretized Encapsulated Electrodes

Plasma actuators (PA) can be utilized as fluid control devices without moving parts, but further improvement in drive efficiency is necessary. Herein, string-type PAs with up to 12 insulated conductive wires were evaluated to replace sheet-type PAs having a single encapsulated electrode. The thrust–power ratio of string-type PAs with eight or more wires is nine times that of a single-wire PA. This is due to the substantial increase in the width of the encapsulated electrode and the discrete arrangement of conductors in the streamwise direction. To determine the factors influencing the performance of PAs with discrete encapsulated electrodes, sheet-type PAs with and without discretized encapsulated electrodes and with the same configuration as string-type PAs were characterized. The measurement results revealed that no significant difference exists in the plasma extension length (LDBD) between sheet-type PAs without and with discretization under the same applied voltage, but 25% and 45% decreases in the thrust and power consumption, respectively, were observed compared to those of string-type PAs. The discretization of the encapsulated electrodes in the sheet-type plasma actuator increased the thrust–power ratio by 30%. Efficient non-mechanical fluid control using dielectric barrier discharge is therefore possible with string-type PAs with discrete electrodes.

Electric Fields in the Vicinity of High-Voltage Power Lines, Optimisation of Power Line Design

This paper presents calculations in the distribution of the electrical fields generated by the potential of phase conductors in overhead high-voltage power lines. The calculations relate to the area between the line paths and the terrain, with particular focus on the area near the ground, which is important in terms of any humans present there, temporarily or permanently. Field intensity distribution is determined for different arrangements of phase conductors and line paths, and for different tower designs. The optimisation criterion is the width of the area excluded from residential development, defined as double the distance from the axis of the line where the electrical field strength exceeds the regulatory permitted 1 kV/m value.

Calculation of Magnetic Flux Density Harmonics in the Vicinity of Overhead Lines

This paper considers the method for the calculation of magnetic flux density in the vicinity of overhead distribution lines which takes into account the higher current harmonics. This method is based on the Biot–Savart law and the complex image method. The considered method calculates the values of the magnetic flux density for each harmonic component of the current separately at all points of interest (usually lateral profile). In this way, it is possible to determine the contributions of individual harmonic components of the current intensity to the total value of magnetic flux density. Based on the contributions of individual harmonic components, the total (resultant) value of the magnetic flux density at points of interest is determined. Validation of the computational method is carried out by comparison of the results obtained by the considered calculation method with measurement results. Furthermore, the application of the calculation method was demonstrated by calculating magnetic flux density harmonics in the vicinity of two overhead distribution lines of typical phase conductor arrangements.

Influence of Medium Voltage Distribution Line Configuration on Phase to Phase Sparkover Rate due to Direct Lightning Strike

In recent years, to reduce maintenance and management cost of distribution facilities, overhead ground wires are sometimes removed in a certain area. In such distribution lines, wire breaking at mid-span due to direct lightning is of concern. Although phase to phase sparkover is considered to be one of the factors of wire breaking at mid-span, its quantitative study has not yet been carried out. In this paper, at first, we experimentally examined detailed sparkover characteristics between phase conductors against short tail lightning impulse voltage, which is assumed to be phase to phase voltage. Next, based on experimental results, we estimate the phase to phase sparkover rate by means of lightning outage calculation program developed by CRIEPI. Estimated results suggest the phase to phase sparkover rate depends on the configuration of distribution lines, such as span length, arrangement of conductors, and so forth.

Optimal parameter estimation of overhead transmission line considering different bundle conductors with the uncertainty of load modeling

AbstractThe overhead power line is used for the transmission and distribution of electrical power across long distances. It consists of multiple conductors mounted on poles or towers. The parameters of the overhead transmission lines (TLs) are dependent upon certain factors that are associated with bundle conductors. This research work uses a whale optimization algorithm (WOA) to calculate the overhead AC TL parameters. The proposed technique is applied to single‐phase and three‐phase AC TLs. It can be observed that within an AC TL, a change in one parameter will cause the corresponding variation in other parameters. This work has determined capacitance and inductance per unit length for three‐phase using proposed WOA algorithms at different bundle conductor arrangements. However, the study of load modeling for voltage stability is also presented.

FDTD Analysis on Propagation and TE Mode Properties of PD‐Emitted Electromagnetic Wave in Three‐Phase Type GIS with a Series Arrangement of HVCs

This article described transverse electric (TE) mode properties of partial discharge‐emitted electromagnetic wave propagating in the three‐phase type gas insulated switchgear (GIS) with a series arrangement of high voltage conductors that was calculated by finite difference time domain (FDTD) method. In the calculation, comparison of TE mode properties between single and three‐phase type GISs as well as discussion on influences of defect position and sensor position were carried out. Also, approximation equation was proposed to obtain the cut‐off frequencies of TE modes in the three‐phase type GIS. © 2021 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC.

Electric Field Investigations of a Compact Superconducting Three-Phase Single Conductor Cable Assembly

A new compact cable design was investigated using only liquid nitrogen (LN <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> ), general used as coolant of superconductors, as sole electric insulation. First, it was analyzed which conductor arrangement is better suited in terms of maximum electric field strength to withstand the applied voltage of 123 kV. It was found that a three-phase single conductor arrangement with a maximum electric field strength of 10.5 kV/mm is more suitable than a triaxial arrangement with a maximum field strength of 16.5 kV/mm. Furthermore, a corresponding supporting insulator was developed to provide the highest possible mechanical and electrical withstand. A major focus was on selecting the most appropriate material and its permittivity in combination with the surrounding LN <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> (ϵ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">r</sub> = 1.43) to reduce the electric field strength to its possible minimum. The best relative permittivity for the supporting insulator is in the range between 1.4 and 3.4.

A Simple Design Method of Unequal Spacing Arrangement for Substation Grounding Grid

To balance the potential distribution on the surface of a substation, an equal spacing arrangement of the grounding grid conductors is not an economical solution. The implementable solution is an unequal placement of its constituent elements. The design methodologies of such a configuration are complex and require computer-assisted numerical analysis. This paper proposes and validates a very simple method, based on an arithmetic progression, of arranging the conductors of the grounding grid that guarantees the reduction of touch and step voltages, ensures the efficiency of the material used and has no limitations on its applicability for atypical substation surfaces (too large or too small), respectively for few or many parallel conductors. To certify the method, the proposed algorithm is analyzed, through the CYMGRD Substation Grounding Program, and compared to the technologies currently applied, for the substation grounding grid presented as an example in the IEEE Guide for Safety in AC Substation Grounding 80™- 2013 standard.