High Voltage Overhead Transmission Lines Research Articles

Thermal analysis for multi-conductor bundle in high voltage overhead transmission lines under the effect of strong wind

Bundle conductors are widely used in HV transmission lines to suppress the corona discharge and reduce the line reactance. To determine its current ampacity of multi-conductor bundle, the thermal analysis is indispensable. A three-dimensional flow-thermal coupling model of multi-conductor bundle considering the effect of strong wind is developed in our study. Using the finite element method, both the temperature field and the fluid field are computed; the characteristics for the multi-physics fields are discussed; the interaction between the fields as well as the mutual influence between subconductors are elucidated. Moreover, a set of sensitivity analysis have been performed, and the effects of load current, conductor spacing, wind speed on temperature field and fluid field are investigated. Based on the pitch-diameter ratio, a novel method to improve the thermal performance of multi-conductor bundle is proposed. Finally, the optimized structure is obtained, and the current ampacity is expected to be greatly enhanced.

Исследование влияния импульсной короны на проводах ВЛ 110 кВ, грозозащитном тросе на энергетические характеристики линейных ОПН во время грозовых перенапряжений

The corona effect has a significant impact on calculations of lightning protection of the high-voltage overhead transmission line. The corona effect in the calculation of the transient process during a lightning overvoltages is often neglected due to the complexity of modeling the corona effect. The issue of the corona effect influence on the operation of non-linear surge suppressors installed on overhead lines hasn’t been sufficiently studied. The aim of the research is to evaluate the energy characteristics of linear surge arresters considering the corona effect on the overhead line. Simulation of the transient process on the overhead line during lightning overvoltages is carried out in the EMTP-ATP software. There is no corona model among the basic models in EMTP-ATP software. Thus, the corona model on overhead line wires using dynamic capacitances is under consideration. A model of corona on overhead line wires in EMTP-ATP is developed. Calculations of energy characteristics of linear surge arresters on an overhead line model considering the corona and without corona effect are carried out. The comparison of the obtained energy characteristics is carried out. The corona has a significant effect on the energy absorbed by the linear surge arresters during lightning strikes to the ground-wire if the front time of the lightning current impulse has a value near 1 s. When lightning strikes to the phase wire, the energy absorbed by the linear surge arresters is so great that the influence of the corona effect is insignificant. The corona model used in calculations in EMTP-ATP software has several limitations. Therefore, in future research it’s advisable to improve the model and simplify it, when calculating lightning protection of overhead lines.

Fault location of high voltage overhead transmission line based on ACO-ENN algorithm.

Fault location of high voltage overhead transmission line based on ACO-ENN algorithm.

Laser nanoengineered coatings for efficient energy transportation through corona discharge suppression

Overhead high-voltage transmission lines are crucial for the modern power transportation industry, but their operation in an open atmosphere raises concerns regarding durability, corona discharge, and leakage currents, which have economic and environmental impacts. To mitigate these issues, new functional materials are being developed using laser nanotechnology, such as superhydrophobic, superhydrophilic, and SLIPS coatings. The suitability of each coating depends on specific operating conditions, requiring a compromise between various wire properties. In this study, we investigated the efficiency of these coatings in reducing corona discharge currents under dry and rainy weather conditions. Our research showed that superhydrophobic and superhydrophilic coatings effectively reduce corona discharge currents by up to 2–4 times, while SLIPS coatings, despite water-repellent properties, increase corona currents in rainy conditions. The obtained results allow suggesting two promising paths toward the improvement of corona protection by enhancing the durability of superhydrophobic coatings under intermittent prolonged rainy conditions and reducing ice adhesion to superhydrophilic coatings.

A New Intelligent Estimation Method Based on the Cascade-Forward Neural Network for the Electric and Magnetic Fields in the Vicinity of the High Voltage Overhead Transmission Lines

The evaluation and estimation of the electric and magnetic field (EMF) intensity in the vicinity of overhead transmission lines (OHTL) is of paramount importance for residents’ healthcare and industrial monitoring purposes. Using artificial intelligence (AI) techniques makes researchers able to estimate EMF with extremely high accuracy in a significantly short time. In this paper, two models based on the Artificial Neural Network (ANN) have been developed for estimating electric and magnetic fields, i.e., feed-forward neural network (FFNN) and cascade-forward neural network (CFNN). By performing the sensitivity analysis on controlling/hyper-parameters of these two ANN models, the best setup resulting in the highest possible accuracy considering their response time has been chosen. Overall, the CFNN achieved a significant 56% reduction in Root Mean Squared Error (RMSE) for the electric field and a 5% reduction for the magnetic field, compared to the FFNN. This indicates that the CFNN model provided more accurate predictions, particularly for the electric field than the proposed methods in other recent works, making it a promising choice for this application. When the model is trained, it will be tested by a different dataset. Then, the accuracy and response time of the model for new data points of that layout will be evaluated through this process. The model can predict the fields with an accuracy near 99.999% of the actual values in times under 10 ms. Also, the results of sensitivity analysis indicated that the CFNN models with triple and double hidden layers are the best options for the electric and magnetic field estimation, respectively.

Identification of Free Components during Non-Simultaneous Complex Faults in Overhead Lines: A Review

This study concerns the identification and interpretation of current and voltage signals during complex non-simultaneous disturbances in high-voltage overhead lines. It includes topics related to both the search for the optimal model of the system during complex disturbances as well as the analysis of the obtained results. The available EMT-like tools for the analysis of these phenomena are discussed. Models of high voltage overhead transmission lines are presented along with a discussion of their suitability for the study of electromagnetic transients during the analysis of complex non-simultaneous faults. Examples of transient waveforms of currents and voltages during non-simultaneous faults are presented, and the conditions for the occurrence of delayed current zero during short circuits in the system are discussed. The maximum values of the overvoltage factors and the conditions of their occurrence are described. Faults in transmission lines with various voltage levels suspended on the same supporting structures are discussed, together with an indication of the dangerous consequences of unusual intersystem faults. In the final part of the paper, the summary and recommendations for non-simultaneous fault studies are presented.

Fault location of high voltage overhead transmission line based on ACO-ENN algorithm

Fault location of high voltage overhead transmission line based on ACO-ENN algorithm

Modelling and design of low-power, non-conventional current sensors based on smart materials for high-voltage transmission lines

This paper presents a new technique for measurement of current based on magnetic shape memory (MSM) smart alloys. MSM alloys undergo shape changes when exposed to magnetic fields. The non-conventional instrument transformer (NCIT) proposed in this paper utilises this property to measure current. There is a correlation between the magnetic field produced by a current and the shape change of an MSM material (MSM sensor). By exploiting this correlation, we have shown that it is possible to measure alternating currents (a.c.) in high voltage overhead transmission lines. A change in the length of the MSM element causes voltage output in a linear variable differential transducer. The design of the NCIT was optimised for transmission lines. Several designs of its magnetic circuit were simulated using finite element package ANSYS APDL. Several key parameters were investigated to evaluate their effects on the sensitivity of the NCIT. Results are presented as the relationship between the current in the conductor and strain (linear elongation) of the MSM element. A commonly used conductor in high-voltage transmission lines was modelled together with the MSM element and the magnetic circuit. Recommendations have been made on the design of NCITs considering various parameters. In addition, analyses of errors in ANSYS models for the magnetic circuit have been presented. The developed methodology and obtained results are verified by comparing them to the results obtained through an experiment done by a manufacturer of MSM materials.

Expansion of high-voltage overhead transmission lines to remote areas

<span>Delivering electrical energy to remote areas is one of the essential things in our modern world. Choosing the optimal route is one of the most critical factors contributing to reducing the power transmission system's cost. Other influencing factors such as the optimum alloy of the conductor wires are difficult to change, so only the aforementioned factor was adopted. In this paper, the optimized potential field algorithm is employed to determine the sub-optimum path that the transmission line should be installed. The best line for the towers is not necessarily the shortest or the cheapest one. Sometimes the best locations for the towers of the transmission lines coming according to the safety regards. It can be said that the best trajectory is a combination of several factors, including the length of the track in addition to other influencing factors depending on the work environment.</span>

CAPACITIVE INFLUENCE OF HIGH VOLTAGE OVERHEAD TRANSMISSION LINES ON THE MEASUREMENT OF SOIL RESISTIVITY

In this article, an analysis is presented of the impact of high voltage overhead transmission lines on the measurement of soil resistivity. Through analysis, the measurement noise level due to the vicinity of the phase conductors of a high voltage overhead transmission line is determined. The soil is modeled as an anisotropic homogeneous half-space of finite resistivity. In order for the article to be of practical use to engineers, simple mathematical instrumentation has been used. Detailed expressions and the physically objective hypotheses under which the cited model is valid have been derived. For the simplicity and generality of the presentation, analysis was performed using a practical example of the measurement of soil resistivity by the Wenner method. The example refers to a single system high voltage transmission line with a steel tower. The results obtained by the theory presented are compared to the results obtained with the software package CDEGS (Current Distribution, Electromagnetic Fields, Grounding and Soil Structure Analysis). The results obtained are presented analytically, graphically and are discussed.

Contamination Level Monitoring Techniques for High-Voltage Insulators: A Review

Insulators are considered one of the most significant parts of power systems which can affect the overall performance of high-voltage (HV) transmission lines and substations. High-voltage (HV) insulators are critical for the successful operation of HV overhead transmission lines, and a failure in any insulator due to contamination can lead to flashover voltage, which will cause a power outage. However, the electrical performance of HV insulators is highly environment sensitive. The main cause of these flashovers in the industrial, agricultural, desert, and coastal areas, is the insulator contamination caused by unfavorable climatic conditions such as dew, fog, or rain. Therefore, the purpose of this work is to review the different methods adopted to identify the contamination level on high-voltage insulators. Several methods have been developed to observe and measure the contamination level on HV insulators, such as leakage current, partial disgorgement, and images with the help of different techniques. Various techniques have been discussed alongside their advantages and disadvantages on the basis of the published research work in the last decade. The major high-voltage insulator contamination level classification techniques discussed include machine learning, fuzzy logic, neuro–fuzzy interface, detrended fluctuation analysis (DFA), and other methods. The contamination level data will aid the scheduling of the extensive and costly substation insulator, and live line washing performed using high-pressured water. As a result, considerable benefits in terms of improved power system reliability and maintenance cost savings will be realized. This paper provides an overview of the different signal processing and machine-learning methods adopted to identify the contamination level on high-voltage insulators. Various methods are studied, and the advantages and disadvantages of each method are discussed. The comprehensive review of the islanding methods will provide power utilities and researchers with a reference and guideline to select the best method to be used for contamination level identification based on their effectiveness and economic feasibility.

Determination of Electric and Magnetic Field Calculation Uncertainty in the Vicinity of Overhead Transmission Lines

This paper presents a new approach for uncertainty determination of the electric field intensity and magnetic flux density calculation in the vicinity of overhead transmission lines. The proposed method is based on the law of propagation of uncertainty as defined in the Guide to the expression of Uncertainty in Measurement. A mathematical model is developed for determining the electric field intensity and magnetic flux density calculation uncertainty based on the Charge simulation method and method based on Biot – Savart law, respectively. The verification of the proposed method was performed by estimating the uncertainty of the electric field and magnetic flux density calculations for four single circuit and two double circuit high-voltage overhead transmission lines. The analysis of the obtained results demonstrates that the proposed method can be successfully used to determine the uncertainty of electric field intensity and magnetic flux density calculations in the vicinity of overhead transmission lines.

Cathodic Protection Performance Improvement of Metallic Pipelines based on Different DC Compensation Methods

• DC voltage has been studied for the pipeline using different types of DC compensation. • An integrated system has been investigated to exploit the harmful induced voltage or external PV system for compensating the cathodic protection disturbances. • Influence of different DC compensation methods using KOH-PCs without and with the FLC on the DC voltage is studied. • A comparative analysis of the UMIV results with PVSP results in terms of saving and discharging energy per year is introduced. Nowadays, natural gas in the Middle East has been discovered in extremely many quantities, and it is considered the most vital natural resource. Sometimes, the natural gas pipeline is constructed in the desert and paralleled with the high voltage overhead transmission lines (HVOHTLs). An induced AC voltage has appeared on the pipeline due to interfering with the HVOHTLs. Mainly, hydroxide potassium polarization cell (KOH-PC) has been applied to discharge this voltage to the soil within a safety limit. But, the mitigation units have negatively impacted cathodic protection (CP). The DC voltage of the pipeline is initially compensated using externally supplied impressed current cathodic protection (IMCP) units. In many cases, the external power sources have continuity and stability issues. Therefore, this paper presents different strategies as a promising solution to be utilized in reducing the disturbance of the external power sources. The first strategy is exploiting the induced voltage via converting it as DC form by using the controlled rectifier circuit and reapplying on the pipeline as a cathodic protection voltage. The second strategy involves a photovoltaic (PV) system, which integrates into the pipeline. This paper also explores the superiorly of the fuzzy system with different compensation strategies in managing the DC voltage along the pipeline to guarantee better CP performance under any disturbance in the impressed current stations. From the comparative analysis, it is observed that the behavior of the various strategies in compensating the DC voltage deterioration is reasonable. The obtained results reveal that the robustness of the fuzzy logic controller in mitigating the induced voltage and has capable of compensating the cathodic protection disturbance.

An energy harvesting reactor for high voltage overhead insulated shield wires considering randomness of meteorological conditions

Harvesting energy from the insulated shield wire with tuning is expected to be a possible solution to the problem of high power supply for online monitoring devices on high voltage overhead transmission lines. However, the randomness of meteorological conditions, such as wind and temperature, may cause fluctuations in the energy harvesting system's power and voltage. This paper presents an integrated energy harvesting reactor with both tuning and transformer functions, which can also consider the randomness of meteorological conditions. The statistical confidence interval of equivalent circuit parameters is numerically calculated based on meteorological data collected along a transmission line for a whole year from 2016 to 2020. On this basis, a combined magnetic circuit for the energy harvesting reactor is proposed to achieve a self-adaptive negative-feedback regulation, and parameter optimization is carried out and validated by field-circuit coupled simulation. Finally, an energy harvesting reactor prototype is developed and tested. The statistical analysis results on the equivalent circuit parameters show that they are approximately subject to Gaussian distribution. Besides, it is found from the experimental results that the maximum power under rated equivalent circuit parameters is 935 W, and the maximum power can reach 800–1000 W within the fluctuation range of equivalent circuit parameters considering meteorological randomness. Overall, the experimental results of the harvested power varying with load resistance conforms to the simulation results. Furthermore, compared to using a deeply saturated tuned reactor, the energy harvesting reactor shows better robustness to the randomness of meteorological conditions and the total harmonic content of output voltage is reduced by 64%. Therefore, the proposed energy harvesting reactor for high voltage overhead insulated shield sires shows more potential for a practical application than the existing methods.

Simple Approximation of the Magnetic Induction Inside High Voltage Overhead Transmission Lines

With the development of electrical power transmission networks, are resulted the increase and continuous consumption of various power production sources, this is what requires the large quantities of energy construction. The increased demand in electric power employment has generated an raised of operating voltage for transmission lines (HV and VHV). The high voltage overhead transmission lines create electric and magnetic fields, and therefore have elevated serious concern questions about their possible potential effects in human body and environmental great associated with the resulting higher levels of electromagnetic fields strength around these power lines. The accurate evaluation of extremely low frequency electromagnetic fields influences produced by the high voltage overhead power lines on human health and the environment are well very known and analysed in several research works and simulation study projects. In this paper we precise examine and present a methodology for plot the lateral profile of magnetic field distribution in close a three-phase overhead transmission line in single circuit flat horizontal configuration at height 1m above the ground level, In order show the essentials factors affecting in the magnetic fields intensity under and in the vicinity of high voltage overhead transmission line in any point of space surface and ground plane, the analytique calculation results of the lateral profile of magnetic flux density behaviour are obtained by program MATLAB software, which makes it possible better analyser and easy represent the transverse profile of the magnetic field around electric power transmission lines, the numerique simulation results are based in image method and the superposition theorem.

Mitigation of the Electric and Magnetic Fields of 500-kV Overhead Transmission Lines

The electric and magnetic fields of overhead high voltage transmission lines are still a critical problem for new construction because of their biological effects on the human body. This issue has been a subject of scientific interest and public concern for the risk of the electric and magnetic fields on living organisms. Accordingly, the overhead transmission lines are considered a source of such this risk due to their high electric and magnetic fields in the populated areas. Because of the recent concerns that electric besides magnetic fields, generated by overhead transmission lines, electric power researchers have been trying to find effective methods for the mitigation of the electrical and magnetic fields to be in the range of acceptable limits. Researchers have been trying to find transmission line geometries that will reduce these electric and magnetic fields. Therefore, in this article two novel methods of reducing the electric and magnetic fields are discussed, one is to change the position of the center phase to optimize the delta configuration and the other is to use more than two shielding wires with calculating the currents in these wires. The obtained results of the two proposed methods are compared with the electric as well as magnetic fields, and the right-of-way values of the present conventional configuration. Additionally, this article presents a case study carried out on an Egyptian 500 kV high voltage overhead transmission line for the mitigation of magnetic and electric field intensities.

A Measurement Method of the Shortest Distance Between Ultrahigh Ships and Transmission Lines Based on Binocular Vision

High voltage overhead transmission lines inevitably cross waterways such as rivers. The insufficient air gap distance between some parts of ultrahigh ships, such as floating crane ships, and transmission lines has caused many transmission lines tripping and even transmission lines to be broken accidents. This paper proposes a measurement method of the shortest distance between ultrahigh ships and transmission lines based on binocular vision for coordinate transformation. The method can measure the shortest distance when the ultrahigh ship will pass under the transmission line in advance. A small simulated experimental platform for measuring the shortest distance between ultrahigh ships and transmission lines based on binocular vision is established. The influence factors on the measurement error of the shortest distance are analyzed on the experimental platform. Based on the simulated small experiment, some suggestions are proposed to extend to the practical application. The results show that the relative error of the shortest distance obtained by the method proposed in this paper is less than 10% in the small simulated experiment, which verifies the method’s effectiveness. This paper’s research will help avoid accidents such as overhead transmission lines being scratched by ultrahigh ships when the overhead transmission lines cross the waterway.

High Voltage Overhead Powerlines Routing in Central Nigeria using GIS-MCDA Approach and Environmental Impact Factors

High voltage overhead transmission line route selection has become a vital component of the power transmission line project life cycle as demand for electricity has increased and global awareness of the environmental implications of large-scale power projects has grown. The project necessitates meticulous planning, engineering designs, facility installations, commissioning, and maintenance, as any errors made at this stage may have a flowing detrimental impact on the following phase, which may be too costly to fix. Using geographic information system (GIS), multi-criteria decision analysis approach, and environmental impact factors strategies, this study determines the best route from existing geographical space between Lafia 330/132/33kV Substation in Nasarawa State and New Apo (Pigba) 330/132/33/kV Substation in the Federal Capital Territory, Central Nigeria, Abuja. Land use, land cover, and other environmental data were obtained by performing image classification on Landsat 8 satellite image using ArcGIS 10.1 to achieve this goal. Three key terrain elements were identified to define the land cover types: built-up areas, vegetation, and water bodies. These layers were created to reveal the locations of significant settlements, geological formations, and the HV-OHTL route that avoided crossing protected areas. Using pair-wise comparison of analytic hierarchy process (AHP) approach, each criterion evaluated was assigned relative weight that shows their level of influence on the proposed power transmission line, and these were provided as GIS layers for visualizations. To build the cost surfaces assessed during route selection for HV-OHTL, weights derived from AHP method for each decision makers were applied to all layers to create the cost surfaces analyzed during route selection for HV-OHTL.

Mitigation of the AC corrosion of the metallic pipelines using the hydroxide and solid-state polarization cells; A comparative study

High voltage overhead transmission lines (HVOHTLs) often pass close to metallic pipelines. The parallelism between HVOHTLs and pipelines, where electromagnetic fields couple them, may cause several problems. If the pipelines are metallic, a corrosion problem has occurred because these fields induce an AC voltage on the pipelines. This paper presents a novel contribution of a low electrical hazard that can control by grounding the pipelines with a polarization cells system to mitigate the induced AC voltage without deteriorating the cathodic protection (CP) performance. This work further utilizes a comparative analysis of two different mitigation units: a potassium hydroxide polarization cell (KOH-PC) and the solid-state polarization cell (SS-PC) to decide which one of these methods is more suitable for cathodic protection distribution. This paper also explores the potential of the hill-climbing algorithm in optimizing the two proposed mitigation units’ parameters to guarantee better CP performance. Moreover, the effect of changing the numbers and parameters of polarization cells on both induced AC voltages and CP performance is introduced to achieve a global minimum DC voltage degradation. From the comparative analysis, it is observed that SS-PC is more controllable in comparison with KOH-PC in mitigating the induced voltage and minimizing the DC voltage disturbance. Therefore, the SS-PC is considered the most efficient mitigation technique due to fewer potential safety hazards produced. The proposed model is implemented through simulations on the MATLAB/Simulink platform with experimental validation. The obtained results reveal that the robustness of SS-PC in mitigating the induced voltage with minimum disturbance in the DC CP voltage. Also, it is found that the effectiveness of the hill-climbing algorithm for optimizing the polarization cell's parameters and has capable of compensating the cathodic protection disturbance.

Non-contact measurement of traveling wave of overhead transmission line

This study proposes a non-contact measurement technique for traveling waves in overhead high-voltage transmission lines. To provide an accurate, efficient, and reliable measurement of the overhead transmission lines, the proposed method utilizes tunnel magnetoresistance sensor arrays that do not require information about the line parameters to evaluate and measure the traveling waves of the overhead transmission line. Further, it diagnoses the operation status of the overhead transmission line by enhancing the system reliability. An experiment is performed to test the feasibility and reliability of the proposed method compared with conventional current transformers. The simulation results demonstrate that the proposed method performs satisfactorily with respect to providing a reliable, cost-effective, and accurate measurement of the traveling waves of overhead transmission lines.