Transmission lines

This research demonstrates that transmission line faults can be classified automatically according to their underlying cause, and lays a foundation for operational classification of transmission line faults in system control centres. The transmission line fault waveforms are characterised by instantaneous symmetrical component analysis to describe the transient and steady state fault conditions. Using a large fault record and waveform database, classification features based on the waveform and external environmental characteristics have been identified to develop single-nearest-neighbour classifiers that identify the underlying cause of transmission line faults, and good classification accuracy has been achieved.

Abstract- Aggregate annual production of made tea in India is empirically analyzed in this study using time series analysis techniques. Important factors affecting tea production are identified and modeled using Vector Autoregressive (VAR) model taking two variables at a time of which one is production, the variable of interest.

O sistema de transmissão de energia elétrica, devido a sua extensão, está sujeito a faltas. Quando uma falta permanete ocorre, a localização dela é crucial para o rápido restaelecimento do sistema. Para localizar o ponto de ocorrência de um curto-circuito fase-terra em uma linha de transmissão hipotética, este trabalho apresenta um algoritimo e código de computador para sistematicamente simular faltas fase-terra em uma linha de transmissão com o EMTP-ATP e treinar uma Rede Neural com tais dados simulados. Para que se tenha um volume grande de dados para treinar a Rede Neural, códigos de computador na linguagem de programação Python foram desenvolvidos de forma a automatizar a criação de arquivos de entrada do EMTP-ATP e a aquisição dos resultados deles. A Rede Neural treinada apresentou um bom desempenho quando testada com os mesmos dados usados para treino dela; porém testes com dados de uma linha de transmissão real durante faltas devem ser feitos.

... along Medium-Length Transmission Line Saleh A. Al-Jufout Tafila Technical University Sabbatical Leave: Al-Hussein Bin Talal University Tafila, Jordan e-mail: drjufout@yahoo.com ... In the same year he joined Al-Balqa' Applied University then Tafila Technical University. ...

This paper provides the complete information related to Right of Way (RoW) for the construction of new power transmission line (TL) in terms of present cost for overhead transmission line and underground XLPE transmission cable. The former part of the paper describes the general procedure and rules for acquisition of land for RoW by transmission asset owner (TAO) while in the later part the cost associated to acquire RoW and its impact on the cost of adjacent land have been detailed. It also discusses the actual dismantling cost including the cost of waste metal what TAO get after completion of lifecycle of  TL due to increase in metal prices. In this paper cost of RoW after completion of lifecycle of TL is also highlighted. This paper compares the cost of RoW for overhead transmission line and underground XLPE transmission cable for construction of new TL. Also for old transmission infrastructure cost of RoW for change from overhead transmission line to underground XLPE transmission cable is detailed by application of replacement model.

LINK: http://link.springer.com/article/10.1007%2Fs40031-013-0067-7

The final publication is available at link.springer.com

Power distribution systems play an important role in modern society. Increasing size and capacity of power systems have rendered them more complex which in turn has led to reduced reliability of such systems. Power distribution systems are always prone to faults. Faults in power systems are generally due to short circuits, lightning etc. Fast and proper restorations of outages are crucial to improve system reliability. For quick and adequate recovery actions such as the determination of the propriety of carrying out forced line charging and the necessity of network switching, and an efficient patrolling, understanding the cause of a fault in an electric power system in the system operation is essential. Moreover, unknown faults may add to unnecessary costs if effective restorations and identifications can’t be done quickly. So, identification of a fault on a transmission line needs to be correct and rapid. However, recognition of the causes of distribution faults accurately generally lack in expert personnel. Also the knowledge about the nature of these faults is not easily transferable from person to person. So, effective means of fault identification needs to be encouraged. In this paper, some of the unconventional approaches for condition monitoring of power systems comprising of wavelet transform, along with the application of soft computing techniques like artificial neural networks, fuzzy logic, support vector machines, genetic algorithm and hybrid combinations based on these have been studied.

ÖZET Gelişen sanayi ile birlikte elektrikli cihazların sayısı ve nüfus artışı sonucunda elektrik ihtiyacı artmaktadır. Artan bu enerji talebiyle birlikte üretilmesi ve iletilmesi gereken enerji miktarı da sürekli bir artış içerisindedir. Talep edilen bu yüksek güçler, elektriğin üretildiği yerden tüketim merkezlerine, genellikle yüksek ve orta gerilim değerlerinde ve hava hatları ile iletilmektedir. Tesis edilecek enerji nakil hatlarının kurulum maliyetleri çok yüksektir. Bu maliyeti etkileyen önemli faktörlerden biri direk boyu, tipi ve sayısıdır. Đletim hattının kurulacağı alan belli olduktan sonra uygun değer direk tipi ve sayısı tespit edilir. Böylece minimum maliyeti ve maksimum güvenliği sağlayacak bir çözüm elde edilmeye çalışılır. Bu çalışmada hesaplamalarda önemli bir faktör olan direk sayısının tespiti için bulanık mantık yöntemi kullanılmıştır. Bulanık mantık tabanlı hesaplamayla elde edilen sonuçların elle yapılan hesaplamayla birebir uyumlu olduğu görülmüştür. ABSTRACT Demand for electricity is increasing as a result of increasing the number of electrical devices with the developing industry and population growth. With the increasing demand for energy, the generation and transmission of the energy required is in a steady increase. Requested that higher powers, where the production of electricity to the consumption centers, generally transmitted by overhead line with high and medium-voltage values. The installation costs of power transmission lines to be established are very high. One of the important factors affecting the cost is the pole length, type and number. After the installation area of the transmission line is specified, optimum type and number of towers is determined. Thus a solution is attempted to provide minimum cost and maximum safety. In this study, fuzzy logic method is used for determining the number of poles which an important factor in the calculations. It can be seen a good agreement between the results obtained by fuzzy-based calculation and made by hand.

En la presente practica de laboratorio, busca comparar los resultados primarios y secundarios de una línea de transmisión obtenidos mediante simulación y cálculos teóricos. Se realizara el proceso de una línea coaxial para la cual se usa la hoja de datos del fabricante y una línea de transmisión bifilar con dimensiones arbitrarias. Las simulaciones se realizan utilizando la licencia estudiantil del software AWR. Abstract-In this laboratory practice, we want to compare the results of primary and secondary parameter of a transmission line, which will be obtained through theoretical equations and simulation. It will be analyzed a coaxial line using the data provided by the manufacturer and a bifilar transmission line with arbitrary dimensions. The simulation will be made using the student license of the AWR software. Palabras Claves Impedancia característica, permitividad, Constante de transmisión, parámetros primarios, parámetros secundarios.

Conductor galloping on overhead transmission lines can be a major problem and the interphase spacers is a countermeasure which has been found to be effective. There is, however, little theoretical basis for their use and for defining their design parameters. In this paper, a galloping simulation model is used in which the aerodynamic force is replaced by a sinusoidal excitation with a frequency equal to the natural vertical galloping frequency of the line. This is used to analyze the ability of interphase spacers to control the galloping amplitude. A full-scale free oscillation test on a triple-span transmission line was conducted and good agreement was obtained with the simulation calculation. Then by simulation, the changes of galloping amplitude and conductor tension were determined in terms of the initial excitation amplitude, both with and without interphase spacers. The dynamic spacer tension during galloping was also computed. The results clearly indicated the effectiveness of interphase spacers to control galloping, and show that the methods used will be useful and applicable to the design of interphase spacers to control galloping and to determine where they can best be deployed.

: El articulo menciona como se puede calcular los parámetros de una línea de transmisión utilizando el software power factory , ingresando los datos de diseño de una linea como son resistividad de suelo , tipo de cable , e incluso las coordenadas de la estructura según para el voltaje que se pretende diseñar

Problems for solving transmission lines problems. Specifically, finding impedance, reflection coefficient, admittance, etc. using Smith Chart. Chapter 2 exercises of the book Fundamentals of Applied Electromagnetics by Ulaby, sixth edition

This paper investigates travelling wave based protection schemes developed for high voltage transmission systems and their adaptation to medium voltage distribution networks in order to enable ultra-high speed relaying (within a quarter of a cycle of the power frequency) on a medium voltage level. This further demonstrates that the travelling wave based protection provides a high speed and very accurate fault detection. The given method compares the polarities of current and voltage travelling waves measured immediately after the fault inception to determine the fault direction.

The technique of cepstrum thresholding, which is shown to be an effective, yet simple, way of obtaining a smoothed non parametric spectrum estimate of a stationary signal. The major problem of this method is the choice of the threshold value for variance reduction of spectrum estimates. This paper proposes a new threshold selection method which is based on cross validation schemes such as Leave-One-Out, Leave-Two-Out and Leave-Half-Out. This new methods are easy to describe, simple to implement, and does not impose severe conditions on the unknown spectrum. Numerical results suggest that this new methods are shown to be in agreement with those obtained when the spectrum is fully known.

Craters, ridges and rocks are the features to be extracted in the lunar images. Proposed methodology deals with detection of linear feature such as (i) ridges, (ii) lineaments and (iii) nonlinear features like craters. All edges are identified as either crater or lineament. Therefore, all circular edges are recognized as craters edges, and those remained edges, which are not crater edges and low possibility of the noise, are recognized as lineaments in the remained edges. The Steps for lineament recognition includes the steps such as Crater Rim Elimination, Small Area Elimination and Lineament Classification. Ridges detection includes edge extraction using haar wavelet transform followed by morphological operations such as dilation and erosion. For detection of non linear features such as craters, the most predominant feature on the lunar terrain, circular hough transform is used. But it fails to detect craters without proper connected edges because of presence of shadows in an image. This paper includes algorithms for shadow removal in the images which accounts for changes in illumination, visual appearance, and size. Results indicate that the detection rate is improved with shadow removal techniques.

Geographical Information System (GIS) and Global Positioning System (GPS) software are widely gaining attention in power system planning and operation. Although commercial systems are increasingly being incorporated in power systems applications, they are yet to be fully incorporated in the routine work of utilities (and especially in the work of crews), due to several reasons such as cost, portability, connectivity, performance/speed, infrastructure etc. This paper focuses on incorporating certain open/free GIS and GPS software in routine transmission line work. The case study is the 150kV transmission systems of the Greek islands of Crete and Rhodes which show increased complexity due to certain localized factors such as Greek legislation, the diverse terrain/routes, the segmented design due to the network's growth over the years (regarding both voltage levels and routes) and the use of different Coordinate Reference Systems (or Geodetic Systems) from the Greek state. The main goals of this work was to incorporate open/free software that provided limitless online access points, offline navigation and a user friendly design that wouldn't require any additional training, programming etc. The basic scheme described in this paper can be followed to provide similar results in other applications.

The purpose of this research is to investigate the severity of voltages induced on gas pipeline (GPL) installed in parallel to a 115-kV overhead transmission line. The overhead transmission line (OHTL) is configured as a single-circuit with a single phase to ground fault occurred on one phase. Transmission of high voltage along the same right of way (ROW) with a metallic conductor may possibly introduce interference on the metallic conductor such as GPL due to power frequency voltage as well as due to phase faults and switching phenomena. Two main approaches were used to compute the induced voltages, namely the method of moment (MOM), which is based on the electromagnetic field theory, and the circuit based method. The simulation considers a 30-km-long OHTL and a 10-km-long GPL. The GPL is buried at 1-m depth in a homogenous earth structure with varying soil resistivites from 10 to 1000 Ω-m. The transmission line consists of 150 towers and 200-m span length. The separation distance between the GPL and OHTL is varied from 5 to 100 m. The phase to ground fault current was varied from 0.5 to 10 kA. Several observation points were made throughout the corridor to examine the induced voltages at different locations. The results show that, the soil resistivity, separation distance, and fault current had significant effects on the GPL induced voltage. In the case of the observation points lying on the soil or on the outer surface of the GPL coating, the induced voltage increases, when the soil resistivity increases, as expected. In contrast, for the observation points placed inside the GPL metal, and the GPL is well coated, the induced voltage decreases when the soil resistivity increases.

Content based image retrieval (CBIR) is the task of searching digital images from a large database based on the extraction of features, such as color, texture and shape of the image. Most of the research in CBIR has been carried out with complete queries which were present in the database. This paper investigates utility of CBIR techniques for retrieval of incomplete and distorted queries. Studies were made in two categories of the query: first is complete and second is incomplete. The query image is considered to be distorted or incomplete image if it has some missing information, some undesirable objects, blurring, noise due to disturbance at the time of image acquisition etc. Color (hue, saturation and value (HSV) color space model) and shape (moment invariants and Fourier descriptor) features are used to represent the image. The algorithm was tested on database consisting of 1875 images. The results show that retrieval accuracy of incomplete queries is highly increased by fusing color and shape features giving precision of 79.87%. MATLAB ® 7.01 and its image processing toolbox have been used to implement the algorithm.

Aggregate annual production of made tea in India is empirically analyzed in this study using time series analysis techniques. Important factors affecting tea production are identified and modeled using Vector Autoregressive (VAR) model taking two variables at a time of which one is production, the variable of interest.

Signal & Image Processing : An International Journal is an Open Access peer-reviewed journal intended for researchers from academia and industry, who are active in the multidisciplinary field of signal & image processing. The scope of the journal covers all theoretical and practical aspects of the Digital Signal Processing & Image processing, from basic research to development of application.

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