Design Of Power Lines Research Articles

Equation of motion of split conductor of anchor section at icing in wind flow

The relevance of the examined problem is connected with the necessity to develop measures to combat conductor galloping and the design of power transmission lines (ETL). The purpose of the research – to analyse statistical observation data on conductor galloping and apply a mathematical model to determine the parameters of galloping, to develop effective measures to combat conductor galloping and to improve the design of power lines. A sophisticated mathematical model was developed using Mathcad software to analyze conductor galloping in overhead power lines. This model, based on the equations of motion, predicts various galloping parameters under different conditions such as wind speed, span length, and initial mechanical stress. Time diagrams were constructed to represent linear and torsional motions, revealing correlations between amplitudes and frequencies. A comprehensive statistical analysis was performed on wire characteristics and split phase parameters to evaluate their impact on galloping patterns. Numerical methods, including the Runge-Kutta method, were employed to solve the equations and compute time-dependent behaviors. Results were visualized through graphs and diagrams to facilitate interpretation. The results revealed that conductor galloping occurs at wind speeds between 5 to 18 m/s, with significant occurrences at temperatures from 0°C to -10°C. The study identified that conductor galloping occurs within a wind velocity range of 5 to 13 m/s, predominantly with wind orientations between 30˚ and 90˚. The analysis showed that the frequency of galloping closely matches the natural oscillation frequency at low wind speeds but diverges with increasing wind speed and span length. These findings provide insights into the conditions under which conductor galloping is likely to occur and can inform design and operational strategies for overhead power lines.

Experimental determination of soil thermal conductivity for design of underground cables

The dimensioning of underground extra-high voltage direct current transmission lines (HVDC) requires detailed knowledge of soil properties, particularly thermal conductivity, to optimise cable spacing and minimise project costs and environmental impact. Given the absence of an internationally standardised procedure for testing soil thermal conductivity, a novel approach was developed as part of the SuedLink project - a 700 km long underground power line which will transmit renewable wind energy between northern and southern Germany. The unique aspect of this methodology lies in its ability to deliver reproducible results of the thermal conductivity of a soil across the entire water content spectrum. This allows the use of realistic thermal conductivity values, as opposed to the current use of overly conservative values in the design of underground power lines. Additionally, the highly efficient testing configuration enables the test to effectively be rolled out on a large scale as was shown with over 6000 tests done on the SuedLink project. This article explains the thermal conductivity test procedure and the evaluation of the raw-data obtained from these tests.

Numerical Analysis and Health Implications of Electric Fields from High Voltage Overhead Transmission Lines for Safety and Design Optimization

This paper calculates and analyses electric fields generated by high-voltage overhead power transmission lines. These fields have significant implications for safety and design considerations. The study utilises a numerical technique to determine the electric field distribution in regions containing multiple charges. Based on this method, a computer program is developed to calculate the electric field profile at ground level and two meters above ground level for both 400 kV overhead power lines. The results demonstrate the method's effectiveness in accurately computing the electric field intensity for various line configurations, making it applicable to any power line design. The paper also highlights the potential health effects associated with exposure to these electric fields, including leukaemia, breast cancer, cognitive impairments, and reproductive consequences. The proposed method can also be applied to other transmission lines, providing valuable insights into health considerations. The accuracy of the computation methods is validated using the finite element analysis method. This research contributes to the understanding and assessing ground-level electric fields, offering industry professionals and researchers valuable insights into the safety and design of power transmission systems.

Design of electrical lines with the DLTCAD software and the improvement in the times of installation processes of electrical lines of antennas in rural areas

This work aims to present the design of power lines with the DLTCAD software and the improvement in the process times for the installation of power lines for antennas in rural areas. Currently in rural areas of Peru the telecommunications service is limited and scarce, with 68.6% access to "Mobile Telephony" and 68.7% access to "Internet" (Source: ERESTEL "Residential Survey of Telecommunications Services", 2021, OSIPTEL), hence the importance of having antennas in rural areas, necessary to provide the telecommunications service to: schools, hospitals, police stations, municipalities, others, and to be able to begin to gradually close the digital gap in our country. DLTCAD is a Peruvian software and one of the best in the world in the calculation and design of power lines. The antennas located in rural areas require electricity for the proper functioning of their equipment, and to be able to operate and radiate the telecommunications service for the benefit of the most needy population with high rates of extreme poverty that do not have basic services such as: water , light and even more so in telecommunications, hence the importance of installing antenna power lines in rural areas, and the importance of designing these power lines with the use of an electrical design tool or software.

Effect of Suspension Clamp Types on the Dynamic Bending Stress of All Aluminium Alloy 1120 Overhead Conductors

Determination of the bending stress is one of the important factors for the design or fatigue assessment of transmission power lines. Researchers and designers calculate the bending stress of overhead conductors by using the Poffenberger–Swart (P-S) formula, which was established for the conductor/metal suspension clamp system. This publication presents experimental work on the effect of different configurations of suspension clamps on the dynamic bending stress that causes fatigue in the conductor. For each type of clamp configuration, specific points of the conductors were instrumented with strain gauges for the measurement of bending strain. The prediction of bending stress by the P-S formula presented errors of up to 140% for clamp different from the one established during the formulation. A better correlation with experimental data was obtained by adjusting considering an effective length of the lever arm for elastomeric clamps.

Investigation the Parameters of Non-Cylindrical Ice Load on Power Transmission Lines

Ice load on transmission lines is a critical factor that affects their cost and operation. National standards specify how ice load is considered in the design of power lines and poles. These standards generally use empirical relations that assume that the ice load on each phase accumulates uniformly and cylindrically. However, field tests and fault records show that the actual ice load on conductors is often not cylindrical due to altitude, wind strength and direction, and terrain topography. This study firstly defines several parameters to describe asymmetrical ice load. This load can cause additional vertical force on the line, conductor swing angle deviation, and sag changes. Since empirical equations are only valid for cylindrical ice load, the cross-sectional shape of the conductor must be transferred to millimeter paper, and calculations performed using one of several numerical integral methods. The coefficients for asymmetric ice are calculated in kg⁄m (N⁄m) using an AutoCAD model in the numerical study.

Некоторые аспекты проблемы защиты птиц от поражения электрическим током на воздушных линиях электропередачи в Казахстане

Некоторые аспекты проблемы защиты птиц от поражения электрическим током на воздушных линиях электропередачи в Казахстане

Accuracy Analysis of Oblique Photogrammetry Measurement in 3D Modeling of Power Line Selection Design

The measurement of power line selection in the field is one of the key works of route design. The traditional manual measurement is inefficient, and ground objects are prone to losses and leakage, often resulting in frequent line changes. With the promotion of 3D real scene work, power line design has also entered the 3D era. In this study, taking the line design near Dengtai Village in Dalian as an example, the UAV is used to carry a multi-viewer camera to obtain three-dimensional information on the ground surface. The power supply line is generally selected in the field far away from residential areas. The characteristics of weak texture bring certain difficulties to the Oblique photogrammetry method. A few control points and checkpoints are arranged to control the accuracy of the ground model, and the accuracy analysis and evaluation are carried out. The results show that the UAV Oblique photography technology has obvious advantages in the process of three-dimensional model construction. The maximum errors of the model result in X, Y, and Z directions are -0.1820 m, -0.1200 m, and -0.3860 m, respectively, the mean square error in the plane is ± 0.0595 m, and the mean square error in elevation is ± 0.2198 m. The 3D model accuracy can meet the actual needs of 1:2000 mapping, thus verifying the feasibility and reliability of the UAV Oblique photography technology to build a high-precision real scene three-dimensional digital model in the application of power line selection measurement.

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.

Techno-design and Aesthetics of Power Lines

The aesthetic aspects of industrial designing are considered. The history and typology of the high-voltage power line kinds are given. The definitions of the design of power line supports and its manifestations in art and mass culture are analyzed. The first and second order design aesthetic component is developed. The power line design cultural aspects have not been fully understood as yet. The power line design also has an influence on socio-cultural life, thereby manifesting itself in the occurrence of new forms of subcultures. Modern power line decorations are a prospect for the development of the suburban landscape and serve as an important element in the image-market formation of energy operators.

Dynamic Response of Transmission Lines Following Ice Shedding via a Three-Dimensional Motion Capture System

The ice shedding may cause the vibration of conductors, and even threaten the safety of towers in severe cases. Based on two test models with a single span and three spans, an advanced three-dimensional motion capture system, the NDI Optotrak Certus System, is used to measure the dynamic response of the conductor following ice shedding. The influences of the ice thickness, ice-shedding ratio, ice-shedding location, and sequence are investigated. The results show that the ice-shedding velocity significantly impacts the dynamic response of conductors, and a larger ice-shedding velocity leads to a smaller jump height. The conclusions drawn from the model tests can guide the deicing and design of power lines.

Optimal Design of Distribution Overhead Powerlines Using Genetic Algorithms

As the design of distribution overhead power lines becomes increasingly standardized in the 21st century, the reduced search space of its design parameters allows for increasing opportunities to automate the design process. It involves specifying the distribution utility pole heights and classes, pole-top attachments, and conductor span tensions. A successful algorithm must be able of generating designs that are compliant with applicable codes and utility standards, achieve construction labour and material costs that are commensurate to that of a human-created design, and require a reasonable computation time. A design automation algorithm is created for ATCO Electricity, Alberta, Canada. Based on provided requirements and constraints, it uses the genetic algorithm to optimize the design parameters, including a completed design staking list, material loading file, and relevant calculation reports for use by the design department. Evaluation of the developed tool is based on five samples of real design scenarios. Within a reasonable amount of computation time, the tool produces results free from major design errors, comparable in material and construction costs to those of human-created designs. Furthermore, the design automation tool makes rigorous use of design decisions that result in small cost savings but that are not commonly found in human-created designs.

Analysis of Non-Uniform Accreted Ice in Overhead Power Lines Using SAP2000

The design principles of overhead power lines cover the effect of external loads in the atmosphere (ice load and wind load) on the layout of power transmission systems. These additional loads are closely related to the geographical and meteorological characteristics of the land, so each country projects the additional loads on the power line design by considering its conditions. The ice load, which should be especially considered in mechanical calculations of power lines, causes forces on the conductor in the vertical direction. However, these vertical forces affect only one part of the conductor in the presence of partial ice, which generally occurs due to falling some ice in the power line to the ground for any reason or directly because of meteorological events and geographical features. The analysis of partial ice load is defined as the non-uniform accreted ice problem in the related studies. This study investigates the effect of non-uniform accreted ice on the conductor curve using data from Turkey. The results obtained from the non-linear model created using SAP2000 (Structural Analysis Program) are verified with the equations in the literature. The proposed model can be used to solve other problems by changing the parameters for cases in different countries.

Audible noise spectral characteristics of high‐voltage ac bundled conductors at high altitude

At high altitudes, the corona discharge around a conductor surface is severe, and the induced audible noise (AN) is irritating; this is due to the low air density at high altitudes. Therefore, AN has become a crucial limiting factor in the design of ac power lines of 500 kV or higher at high altitudes. An investigation of the spectral characteristics of AN should help provide a greater understanding of corona noise; however, only a few studies have investigated the spectral characteristics of AN in practical bundled conductors at high altitude. Therefore, it is difficult for power utility companies to select suitable conductors. In this study, the AN spectral characteristics of 6 × LGJ400, 6 × LGJ720, and 8 × LGJ500 bundled conductors were investigated using an ultra-high-voltage corona cage (8 × 8 × 35 m) in Xining, Qinghai Province (altitude: 2261 m). The AN equivalent A-weighted level and the 1/3-octave frequency characteristics of these three conductors were obtained, and the influence of the electric field (E-field) on these characteristics was analysed. Subsequently, the relationship between the AN A-weighted level and the 8-kHz level was examined. We found that, with the increase of the E-field, the low-frequency components of AN level did not exhibit an obvious trend, but in the high-frequency band (1.6–20 kHz), a clear positive correlation was observed between the spectrum level and E-field strength. Among these three conductors, the 8 × LGJ500 conductor was the optimal conductor for reducing the AN levels at high altitude. The results obtained in this study can provide a data reference for the construction of high-altitude ac power lines.

A Didactic Procedure to Solve the Equation of Steady-Static Response in Suspended Cables

Students in the electrical branch of the short-cycle tertiary education program acquire developmental and design skills for low voltage transmission power lines. Aerial power line design requires mathematical tools not covered well enough in the curricula. Designing suspension cables requires the use of a Taylor series and integral calculation to obtain the parabola’s arc length. Moreover, it requires iterative procedures, such as the Newton–Raphson method, to solve the third-order equation of the steady-static response. The aim of this work is to solve the steady-static response equation for suspended cables using simple calculation tools. For this purpose, the influence of the horizontal component of the cable tension on its curvature was decoupled from the cable’s self-weight, which was responsible for the tension’s vertical component. To this end, we analyzed the laying and operation of the suspended cables by defining three phases (i.e., stressing, lifting, and operation). The phenomena that occurred in each phase were analyzed, as was their manifestation in the cable model. Herein, we developed and validated the solution of the steady-static response equation in suspended cables using simple equations supported with intuitive graphics. The best results of the proposed calculation procedure were obtained in conditions of large temperature variations.

Stochastic optimization method for mechanical design of overhead distribution power lines

ABSTRACTThis article presents a stochastic optimization method for the mechanical dimensioning problem of overhead distribution power lines. For this purpose, an algorithm tailored for solving mixed integer programming problems based on the MI-LXPM algorithm was developed, which, associated with the unscented transform, allows the uncertainty inherent in the wind speed to be considered during the optimization process, with fewer evaluations than required by Monte Carlo methods. An on-the-fly population size adjustment algorithm was used, which allows the required number of evaluations to reach solutions to be reduced further. When compared to a traditional optimization process with deterministic parameters, the results of the proposed method present considerably superior reliability in the case studied, producing a reliable solution in 90.42% of all simulations, while the former produced only 76.39%.

Research on Safety Assessment for Power Line Design

As the source of power line project, line design is a key part of life cycle management. The safety and reliability of line design can provide necessary support for construction, operation and maintenance. This paper proposes a risk-based approach for safety management in line design, decomposing risks into two dimensions, the probability and the consequence. Based on factors, such as risk assessment, number of historical incidents, consequence of historical incidents, qualification of proofreading and auditing, this approach in line design can predict risk status in real time, provide scientific basis for risk control, and minimize safety hazards.

Corona Onset Characteristics of Bundle Conductors in UHV AC Power Lines at 2200 m Altitude

The corona onset characteristic of bundle conductors is an important limiting factor for the design of UHV AC power lines in high-altitude areas. An experimental study on the corona characteristics of 8 × LGJ630, 6 × LGJ720, 8 × LGJ720 and 10 × LGJ720 bundle conductors commonly used in UHV power lines under dry and wet conductor conditions, as well as artificial moderate and heavy rain conditions, was conducted in Ping’an County, Xining City (elevation 2200 m). By using the tangent line method, the corona onset voltages and onset electric field of four types of conductors at high altitudes are obtained for the first time. In addition, the calculation model of corona onset voltage considering the outer strands’ effect on the electric field and the geometric factor in the corona cage in high altitude areas is established. The comparison of the calculation results and experimental results under dry conditions verifies the model’s correctness. Based on the results, an optimal selection scheme for high altitudes is proposed. The roughness coefficient was also calculated and analysed: the roughness coefficient of bundled conductors was between 0.59 and 0.77, and the roughness coefficient of the wet conductor was between the dry and rainy conditions. Both the experimental data and the calculation model can provide a reference for conductor selection for UHV AC power lines for use in high-altitude areas.

Амплитудные значения падающей и отраженной волн в линии электропередачи трехпроводного исполнения

The transmission of electrical energy along the power lines is effected due to the electromagnetic field waves. In the three-wire power lines the transmission of electrical energy is provided for with three pairs of waves, each containing a falling and a reflected one. The amplitudes of these waves define the voltage and current values in the power lines. The article presents a diagram of the falling and reflected waves amplitude values distribution along a uniform section of a three-wire power line. It shows that electromagnetic waves amplitude values define integration constants. The diagram of the electromagnetic waves amplitude values distribution along the line wire of a three-wire power line shows that that the adjacent current carrying parts significantly impact the voltage and current values of the wire. This diagram is an functional means allowing determining the integration constants values. When the propagation constants of electromagnetic waves on the line conductors of the power line and the appropriate wave resistances are known, these values can be used to define the amplitude values of the falling and reflected modes along all power line. The outcomes of the research can be used in design, reconstruction, and maintenance of three-wire power lines to forecast the voltage and current values in different sections of a power line. Forecasting the amplitude values of the falling and reflected electromagnetic waves in the line wires of double-circuit transmission lines shall allow for the detailed analysis of voltages and currents in a uniform section of a power line. The suggested technique may also be applied for low-quality electric energy.

Effect of Altitude on the Audible Noise Level of AC Power lines

The audible noise (AN) induced by corona discharge of AC transmission lines is more severe at high altitudes than at low altitudes; this has become a crucial limiting factor for the structural design of power lines and their environmental impact assessment. To determine the altitude effect and correction of AN level for AC power lines, a corona cage test system was used to measure the acoustic power level of four bundled conductors at five elevations, namely Wuhan (23 m), Tianshui (1100 m), Xining (2261 m), Gonghe (2943 m), and Yangbajain (4300 m). We obtained the AN characteristics for different altitudes, bundle numbers, and subconductor diameters through a statistical analysis of measured data. The analysis and comparison results indicate that the actual AN correction values are slightly less than the Bonneville Power Administration term of 1 dB/300 m at altitudes below 3200 m. Above 3200 m, the difference increases gradually. A correction term 2.85 dB/1000 m is recommended for more accurate evaluation.