This document presents a study on how the semiconductor layers in underground cables can affect Time Domain Reflectometry (TDR) measurements. The researchers developed a circuit model that includes the electrical resistance of the semiconductor layers to better simulate TDR signals. Simulations using the proposed model showed good agreement with measurements from a new cable but not an aged cable. The model was updated to represent resistance in the aged cable's semiconductor layers caused by degradation over time. Simulations with this updated model matched experimental TDR results from the aged cable better than the original model. The study demonstrates that changes in semiconductor layer resistance due to aging can impact TDR pulse propagation in cables.
Mutual Coupling Reduction in Antenna Using EBG on Double SubstrateTELKOMNIKA JOURNAL
Malaysia
*Corresponding author, e-mail: raimidewan@gmail.com
Abstract
In this paper, a mutual coupling study is conducted between two-element array
antenna on dual substrate. A single patch antenna is firstly designed on dual substrate layer to
testify appropriate performance at 2.45 GHz. Subsequently, an array of two element patches on
dual substrate are constructed with one of them is incorporated with three EBG unit cell on the
bottom substrate. The radiating patch is on the top substrate, while the EBG unit cell is on the
bottom substrate. With EBGs in separate layers from the antenna array, the antenna elements
are closely separated by a distance of 22 mm with a significant reduced mutual coupling of -
26.61 dB. This corresponds to a distance reduction of 34.68%. The proposed structure
implemented only three EBG unit cells. Apart from that, the study of overlapped case of EBG
with the antenna is also presented.
Mutual Coupling Reduction in Antenna Using EBG on Double SubstrateTELKOMNIKA JOURNAL
Malaysia
*Corresponding author, e-mail: raimidewan@gmail.com
Abstract
In this paper, a mutual coupling study is conducted between two-element array
antenna on dual substrate. A single patch antenna is firstly designed on dual substrate layer to
testify appropriate performance at 2.45 GHz. Subsequently, an array of two element patches on
dual substrate are constructed with one of them is incorporated with three EBG unit cell on the
bottom substrate. The radiating patch is on the top substrate, while the EBG unit cell is on the
bottom substrate. With EBGs in separate layers from the antenna array, the antenna elements
are closely separated by a distance of 22 mm with a significant reduced mutual coupling of -
26.61 dB. This corresponds to a distance reduction of 34.68%. The proposed structure
implemented only three EBG unit cells. Apart from that, the study of overlapped case of EBG
with the antenna is also presented.
Flexible Wearable Antenna on Electromagnetic Band Gap using PDMS substrateTELKOMNIKA JOURNAL
A robust and low-profile electromagnetic band-gap (EBG) based on flexible wearable antenna covering 2.4 GHz frequency band is presented. The incorporated EBG with antenna reduces the radiation into the human body around 17 dB and decreases the impacts of frequency detuning. The overall dimension of the antenna integrated with EBG is 56 x 56 x 4 mm3 with relative impedance bandwidth of 8.3% is achieved. The proposed design has improved the gain up to 7 dBi. Specific absorption rate (SAR) assessment is also studied to certify the performance of the antenna when it is located proximity to human tissue. The flexible antenna with aforementioned performances could be chosen as a good candidate for integration into a range of wearable devices for medical application.
Design of c slotted microstrip antenna using artificial neural network modeleSAT Journals
Abstract In this paper, neural network model has been used to estimation of resonance frequency of a coaxial feed C-slotted Microstrip Antenna. The Multi-Layer Perceptron Feed forward back Propagation (MLPFFBP) and Radial basis function Artificial Neural Network (RBFANN) have been used to implement the neural network model. A relative performance analysis of the proposed neural network for different training algorithms. Number of neurons and number of hidden layer is also carried out for estimating the resonance frequency. The method of moment (MOM) based IE3D software was used to generate data dictionary for training and validation set of ANN. The results obtain using ANN are compared with simulation feeding and found quite satisfactory and also it is concluded that RBFANN network is more accurate and fast compared to MLPFFBP network algorithm. Index Terms: Artificial Neural Network, C slot, Microstrip Antenna, Multilayer Feed Forward Networks, Radial basis function Artificial Neural Network, Resonance frequency.
Extended electrical tuning of quantum cascade lasers with digitalSepehrAzureSky
In this report, the sampled grating distributed feedback laser architecture is modified with digital
concatenated gratings to partially compensate for the wavelength dependence of optical gain in a
standard high efficiency quantum cascade laser core. This allows equalization of laser threshold
over a wide wavelength range and demonstration of wide electrical tuning. With only two
control currents, a full tuning range of 500 nm (236 cm1
) has been demonstrated. Emission is
single mode, with a side mode suppression of >20 dB. V C 2013 AIP Publishing LLC.
[http://dx.doi.org/10.1063/1.4841635]
An introduction to the fundamental physics of transparent conducting oxides including a review of the electrical and optical properties of common materials.
International Refereed Journal of Engineering and Science (IRJES)irjes
The core of the vision IRJES is to disseminate new knowledge and technology for the benefit of all, ranging from academic research and professional communities to industry professionals in a range of topics in computer science and engineering. It also provides a place for high-caliber researchers, practitioners and PhD students to present ongoing research and development in these areas.
Non-split Perfectly Matched Layer Boundary Conditions for Numerical Solution ...ijeljournal
This paper developed a non - split perfectly matched layer (PML) boundary condition (BC) for Finite Difference Time Domain (FDTD) simulation of electromagnetic wave propagation in 2D structure. The point source for electric field has been exploited for propagation of electromagnetic field through 2D structures to validate developed approach. The identity of resulted field distribution to that obtained for split PML BC have been demonstrated.
NON-SPLIT PERFECTLY MATCHED LAYER BOUNDARY CONDITIONS FOR NUMERICAL SOLUTION ...ijeljournal
This paper developed a non - split perfectly matched layer (PML) boundary condition (BC) for Finite Difference Time Domain (FDTD) simulation of electromagnetic wave propagation in 2D structure. The
point source for electric field has been exploited for propagation of electromagnetic field through 2D structures to validate developed approach. The identity of resulted field distribution to that obtained for split PML BC have been demonstrated.
Abstract: While designing a cellular network, the main issue for the network planning is to achieve maximum
capacity while maintaining an acceptable grade of service and good speech quality. Planning an immature
network does not allow future growth and expansion. Wise & calculative re-use of site location in the future
network structure will save money for the operator. For this reason, digital maps are one of the most essential
elements to the network engineers while they have to think about expanding their business. However, the digital
maps cost a lot of money. This problem can be mitigated if Google Earth is used.
In this paper, the procedure of how to design a cellular digitized map on Google Earth is shown. By
calculating the cell radius, implementing the single cell site, forming the 7-cell cluster and all the cells a low
cost digitized map is designed. It is necessary to have a digitized map in mobile communication because
ultimate goal includes efficient usage of RF wave, frequency reuse, total use of BW and last but not the least
cost reduction.
Keywords: Cellular digitized map, Cell radius, Google Earth.
Flexible Wearable Antenna on Electromagnetic Band Gap using PDMS substrateTELKOMNIKA JOURNAL
A robust and low-profile electromagnetic band-gap (EBG) based on flexible wearable antenna covering 2.4 GHz frequency band is presented. The incorporated EBG with antenna reduces the radiation into the human body around 17 dB and decreases the impacts of frequency detuning. The overall dimension of the antenna integrated with EBG is 56 x 56 x 4 mm3 with relative impedance bandwidth of 8.3% is achieved. The proposed design has improved the gain up to 7 dBi. Specific absorption rate (SAR) assessment is also studied to certify the performance of the antenna when it is located proximity to human tissue. The flexible antenna with aforementioned performances could be chosen as a good candidate for integration into a range of wearable devices for medical application.
Design of c slotted microstrip antenna using artificial neural network modeleSAT Journals
Abstract In this paper, neural network model has been used to estimation of resonance frequency of a coaxial feed C-slotted Microstrip Antenna. The Multi-Layer Perceptron Feed forward back Propagation (MLPFFBP) and Radial basis function Artificial Neural Network (RBFANN) have been used to implement the neural network model. A relative performance analysis of the proposed neural network for different training algorithms. Number of neurons and number of hidden layer is also carried out for estimating the resonance frequency. The method of moment (MOM) based IE3D software was used to generate data dictionary for training and validation set of ANN. The results obtain using ANN are compared with simulation feeding and found quite satisfactory and also it is concluded that RBFANN network is more accurate and fast compared to MLPFFBP network algorithm. Index Terms: Artificial Neural Network, C slot, Microstrip Antenna, Multilayer Feed Forward Networks, Radial basis function Artificial Neural Network, Resonance frequency.
Extended electrical tuning of quantum cascade lasers with digitalSepehrAzureSky
In this report, the sampled grating distributed feedback laser architecture is modified with digital
concatenated gratings to partially compensate for the wavelength dependence of optical gain in a
standard high efficiency quantum cascade laser core. This allows equalization of laser threshold
over a wide wavelength range and demonstration of wide electrical tuning. With only two
control currents, a full tuning range of 500 nm (236 cm1
) has been demonstrated. Emission is
single mode, with a side mode suppression of >20 dB. V C 2013 AIP Publishing LLC.
[http://dx.doi.org/10.1063/1.4841635]
An introduction to the fundamental physics of transparent conducting oxides including a review of the electrical and optical properties of common materials.
International Refereed Journal of Engineering and Science (IRJES)irjes
The core of the vision IRJES is to disseminate new knowledge and technology for the benefit of all, ranging from academic research and professional communities to industry professionals in a range of topics in computer science and engineering. It also provides a place for high-caliber researchers, practitioners and PhD students to present ongoing research and development in these areas.
Non-split Perfectly Matched Layer Boundary Conditions for Numerical Solution ...ijeljournal
This paper developed a non - split perfectly matched layer (PML) boundary condition (BC) for Finite Difference Time Domain (FDTD) simulation of electromagnetic wave propagation in 2D structure. The point source for electric field has been exploited for propagation of electromagnetic field through 2D structures to validate developed approach. The identity of resulted field distribution to that obtained for split PML BC have been demonstrated.
NON-SPLIT PERFECTLY MATCHED LAYER BOUNDARY CONDITIONS FOR NUMERICAL SOLUTION ...ijeljournal
This paper developed a non - split perfectly matched layer (PML) boundary condition (BC) for Finite Difference Time Domain (FDTD) simulation of electromagnetic wave propagation in 2D structure. The
point source for electric field has been exploited for propagation of electromagnetic field through 2D structures to validate developed approach. The identity of resulted field distribution to that obtained for split PML BC have been demonstrated.
Abstract: While designing a cellular network, the main issue for the network planning is to achieve maximum
capacity while maintaining an acceptable grade of service and good speech quality. Planning an immature
network does not allow future growth and expansion. Wise & calculative re-use of site location in the future
network structure will save money for the operator. For this reason, digital maps are one of the most essential
elements to the network engineers while they have to think about expanding their business. However, the digital
maps cost a lot of money. This problem can be mitigated if Google Earth is used.
In this paper, the procedure of how to design a cellular digitized map on Google Earth is shown. By
calculating the cell radius, implementing the single cell site, forming the 7-cell cluster and all the cells a low
cost digitized map is designed. It is necessary to have a digitized map in mobile communication because
ultimate goal includes efficient usage of RF wave, frequency reuse, total use of BW and last but not the least
cost reduction.
Keywords: Cellular digitized map, Cell radius, Google Earth.
IOSR Journal of Applied Physics (IOSR-JAP) is an open access international journal that provides rapid publication (within a month) of articles in all areas of physics and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in applied physics. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Educational Process Mining-Different PerspectivesIOSR Journals
Process mining methods have in recent years enabled the development of more sophisticated Process
models which represent and detect a broader range of student behaviors than was previously possible. This
paper summarizes key Process mining perspectives that have supported student modeling efforts, discussing
also the specific constructs that have been modeled with the use of educational process mining and key
upcoming directions that are needed for educational process mining research to reach its full potential. Process
mining aims to discover, monitor and improve real processes by extracting knowledge from event logs readily
available in today’s information systems. This paper is designed to give a view on the capabilities of process
mining techniques in the context of higher education system which involves and deals with administrative and
academic tasks like enrolment of students in a particular case, alienation of traditional classroom teaching
model, detection of unfair means used in online examination, detection of abnormal values in the result sheet of
students, prediction about students performance, identify the drop outs, and students who need special attention
and allow the teacher to provide appropriate advising /counseling and so on.
Analysis of failure of Brakes due to leakages of cylinder through CFDIOSR Journals
Today’s world is very fast moving and in this world we all are well understand that the how
important brake is? Effectiveness of braking system are essentials part to avoid accidents and save life. Also
majority of accidents in vehicles are happen due to chassis failure and braking failure. Here I take the subject to
understand the causes of failure of hydraulic brake systems in SUV. The brakes are the most important
active safety of a car and one of its key pieces. However, many drivers do not seem to understand it well.
According to a statistics, about 40% of the defects detected by the ITV correspond to the brakes. It is not enough
to bring the car to the shop when something goes wrong.
Leakage is major problem in TMC. In any case if tmc leak it may leads to accident. So
leakage and performance of tmc is most important. Various parts of tmc such as piston, spring does not leak.
The body of tmc may leak as well seals used in assembly of piston.
In this project the different reasons of leakages are finding and simulation with CFD are carried out
IOSR Journal of Humanities and Social Science is an International Journal edited by International Organization of Scientific Research (IOSR).The Journal provides a common forum where all aspects of humanities and social sciences are presented. IOSR-JHSS publishes original papers, review papers, conceptual framework, analytical and simulation models, case studies, empirical research, technical notes etc.
International Journal of Engineering Research and DevelopmentIJERD Editor
Electrical, Electronics and Computer Engineering,
Information Engineering and Technology,
Mechanical, Industrial and Manufacturing Engineering,
Automation and Mechatronics Engineering,
Material and Chemical Engineering,
Civil and Architecture Engineering,
Biotechnology and Bio Engineering,
Environmental Engineering,
Petroleum and Mining Engineering,
Marine and Agriculture engineering,
Aerospace Engineering.
3 d single gaas co axial nanowire solar cell for nanopillar-array photovoltai...ijcsa
Nanopillar array photovoltaics give unique advantages over today’s planar thin films in the areas of
optical properties and carrier collection, arising from their 3D geometry. The choice of the material
system, however, is essential in order to gain the advantage of the large surface/interface area associated
with nanopillars. Therefore, a well known Si and GaAs material are used in the design and studied in this
nanowire application. This work calculates and analyses the performance of the coaxial GaAs nanowire
and compared with that of Si nanowire using a semi-classical method. The current-voltage characteristics
are investigated for both under dark and AM1.5G illumination. It is found that GaAs nanowire gives almost
double efficiency with its counterpart Si nanowire. Their TCAD simulations can be validated reasonably
with that of published experimental result.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
Simulation Of Algan/Si And Inn/Si Electric - Devicesijrap
In this work, efficient solar-blind metal-semiconductor photodetectors grown on Si (111) by
molecular beam epitaxy are reported. Growth details are described,the comparison enters the
properties electric of InN/Si and AlGaN/Si photodectors with 0.2 µm of AlGaN and InN layers.
Modeling and simulation were performed by using ATLAS-TCAD simulator. Energy band
diagram, doping profile, conduction current density,I-V caracteristic , internal potential and
electric field were performed.
Simulation of AlGaN/Si and InN/Si ELECTRIC –DEVICESijrap
In this work, efficient solar-blind metal-semiconductor photodetectors grown on Si (111) by
molecular beam epitaxy are reported. Growth details are described,the comparison enters the
properties electric of InN/Si and AlGaN/Si photodectors with 0.2 μm of AlGaN and InN layers.
Modeling and simulation were performed by using ATLAS-TCAD simulator. Energy band
diagram, doping profile, conduction current density,I-V caracteristic , internal potential and
electric field were performed.
Simulation of AlGaN/Si and InN/Si ELECTRIC –DEVICESijrap
In this work, efficient solar-blind metal-semiconductor photodetectors grown on Si (111) by
molecular beam epitaxy are reported. Growth details are described,the comparison enters the
properties electric of InN/Si and AlGaN/Si photodectors with 0.2 µm of AlGaN and InN layers.
Modeling and simulation were performed by using ATLAS-TCAD simulator. Energy band
diagram, doping profile, conduction current density,I-V caracteristic , internal potential and
electric field were performed
Fea of pcb multilayer stack up high voltage planar transformer for aerospace...elelijjournal
High voltage planar transformer is a technology which can replace conventional transformer with its distinct advantages of saturation and cost efficiency. This paper includes, study and solution methods for PCB winding configuration in planar magnetic elements with multilayer
stack up of PCB Cu-tracks, producing High voltage power supply for aerospace application.With finite element analysis (FEA) simulations, different simulation outcomes are discussed for inspecting flux intensity and current density distribution with computing Electric field strength
and Magnetic fields. In principal conclusion of study, complete analysis and some practical design guidelines for
multilayer PCB stack up are discussed in this paper.
Flexible and Ultrasoft Inorganic 1D Semiconductor and Heterostructure Systems...Pawan Kumar
Low dimensionality and high flexibility are key demands for flexible electronic semiconductor devices. SnIP, the first atomic-scale double helical semiconductor combines structural anisotropy and robustness with exceptional electronic properties. The benefit of the double helix, combined with a diverse structure on the nanoscale, ranging from strong covalent bonding to weak van der Waals interactions, and the large structure and property anisotropy offer substantial potential for applications in energy conversion and water splitting. It represents the next logical step in downscaling the inorganic semiconductors from classical 3D systems, via 2D semiconductors like MXenes or transition metal dichalcogenides, to the first downsizeable, polymer-like atomic-scale 1D semiconductor SnIP. SnIP shows intriguing mechanical properties featuring a bulk modulus three times lower than any IV, III-V, or II-VI semiconductor. In situ bending tests substantiate that pure SnIP fibers can be bent without an effect on their bonding properties. Organic and inorganic hybrids are prepared illustrating that SnIP is a candidate to fabricate flexible 1D composites for energy conversion and water splitting applications. SnIP@C3N4 hybrid forms an unusual soft material core–shell topology with graphenic carbon nitride wrapping around SnIP. A 1D van der Waals heterostructure is formed capable of performing effective water splitting.
Analysis of Stranded Multi-Conductor Cable in Multilayered Dielectric MediaJimmi James
ABSTRACT
Due to complexity of electromagnetic modeling, researchers and scientists always look for development of accurate and fast methods to extract the parameters of electronic transmission cables. These parameters play a critical role in various applications like electro surgery, fault location in cables and many more. In this paper, the modeling of stranded multiconductor cable in multilayered dielectric media is illustrated. We specifically determine the distributed parameters of two wire transmission lines in two-layered dielectric media. The effect of frequency change on the parameters is also discussed. This numerical analysis was successfully implemented for modeling of a cable which connects the hand piece of an electro surgical device to its generator. Comparison of the theoretical and the practically measured results is demonstrated with good agreements.
Analysis and optimization of wireless power transfer linkAjay Kumar Sah
In this paper, a high efficiency Gallium nitride (GaN), HEMT (High Electron Mobility Transistor) class-E power amplifier for the wireless power transfer link is designed and simulated on PSpice. A four-coil wireless power transfer link is modeled for maximum power transfer efficiency on ADS (Advanced Design System) and frequency splitting phenomenon is demonstrated, explained and analyzed. Two resonant coupling structures, series & mixed, are presented and compared. The efficiency performance of the link is studied using spiral and helical antennas of different wire make. In addition, techniques for improving efficiency of the wireless power transfer systems with changing coupling coefficient viz. frequency splitting phenomenon of the coils are proposed.
Automobile Management System Project Report.pdfKamal Acharya
The proposed project is developed to manage the automobile in the automobile dealer company. The main module in this project is login, automobile management, customer management, sales, complaints and reports. The first module is the login. The automobile showroom owner should login to the project for usage. The username and password are verified and if it is correct, next form opens. If the username and password are not correct, it shows the error message.
When a customer search for a automobile, if the automobile is available, they will be taken to a page that shows the details of the automobile including automobile name, automobile ID, quantity, price etc. “Automobile Management System” is useful for maintaining automobiles, customers effectively and hence helps for establishing good relation between customer and automobile organization. It contains various customized modules for effectively maintaining automobiles and stock information accurately and safely.
When the automobile is sold to the customer, stock will be reduced automatically. When a new purchase is made, stock will be increased automatically. While selecting automobiles for sale, the proposed software will automatically check for total number of available stock of that particular item, if the total stock of that particular item is less than 5, software will notify the user to purchase the particular item.
Also when the user tries to sale items which are not in stock, the system will prompt the user that the stock is not enough. Customers of this system can search for a automobile; can purchase a automobile easily by selecting fast. On the other hand the stock of automobiles can be maintained perfectly by the automobile shop manager overcoming the drawbacks of existing system.
Hybrid optimization of pumped hydro system and solar- Engr. Abdul-Azeez.pdffxintegritypublishin
Advancements in technology unveil a myriad of electrical and electronic breakthroughs geared towards efficiently harnessing limited resources to meet human energy demands. The optimization of hybrid solar PV panels and pumped hydro energy supply systems plays a pivotal role in utilizing natural resources effectively. This initiative not only benefits humanity but also fosters environmental sustainability. The study investigated the design optimization of these hybrid systems, focusing on understanding solar radiation patterns, identifying geographical influences on solar radiation, formulating a mathematical model for system optimization, and determining the optimal configuration of PV panels and pumped hydro storage. Through a comparative analysis approach and eight weeks of data collection, the study addressed key research questions related to solar radiation patterns and optimal system design. The findings highlighted regions with heightened solar radiation levels, showcasing substantial potential for power generation and emphasizing the system's efficiency. Optimizing system design significantly boosted power generation, promoted renewable energy utilization, and enhanced energy storage capacity. The study underscored the benefits of optimizing hybrid solar PV panels and pumped hydro energy supply systems for sustainable energy usage. Optimizing the design of solar PV panels and pumped hydro energy supply systems as examined across diverse climatic conditions in a developing country, not only enhances power generation but also improves the integration of renewable energy sources and boosts energy storage capacities, particularly beneficial for less economically prosperous regions. Additionally, the study provides valuable insights for advancing energy research in economically viable areas. Recommendations included conducting site-specific assessments, utilizing advanced modeling tools, implementing regular maintenance protocols, and enhancing communication among system components.
Water scarcity is the lack of fresh water resources to meet the standard water demand. There are two type of water scarcity. One is physical. The other is economic water scarcity.
NO1 Uk best vashikaran specialist in delhi vashikaran baba near me online vas...Amil Baba Dawood bangali
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Vaccine management system project report documentation..pdfKamal Acharya
The Division of Vaccine and Immunization is facing increasing difficulty monitoring vaccines and other commodities distribution once they have been distributed from the national stores. With the introduction of new vaccines, more challenges have been anticipated with this additions posing serious threat to the already over strained vaccine supply chain system in Kenya.
Immunizing Image Classifiers Against Localized Adversary Attacksgerogepatton
This paper addresses the vulnerability of deep learning models, particularly convolutional neural networks
(CNN)s, to adversarial attacks and presents a proactive training technique designed to counter them. We
introduce a novel volumization algorithm, which transforms 2D images into 3D volumetric representations.
When combined with 3D convolution and deep curriculum learning optimization (CLO), itsignificantly improves
the immunity of models against localized universal attacks by up to 40%. We evaluate our proposed approach
using contemporary CNN architectures and the modified Canadian Institute for Advanced Research (CIFAR-10
and CIFAR-100) and ImageNet Large Scale Visual Recognition Challenge (ILSVRC12) datasets, showcasing
accuracy improvements over previous techniques. The results indicate that the combination of the volumetric
input and curriculum learning holds significant promise for mitigating adversarial attacks without necessitating
adversary training.
Courier management system project report.pdfKamal Acharya
It is now-a-days very important for the people to send or receive articles like imported furniture, electronic items, gifts, business goods and the like. People depend vastly on different transport systems which mostly use the manual way of receiving and delivering the articles. There is no way to track the articles till they are received and there is no way to let the customer know what happened in transit, once he booked some articles. In such a situation, we need a system which completely computerizes the cargo activities including time to time tracking of the articles sent. This need is fulfilled by Courier Management System software which is online software for the cargo management people that enables them to receive the goods from a source and send them to a required destination and track their status from time to time.
TECHNICAL TRAINING MANUAL GENERAL FAMILIARIZATION COURSEDuvanRamosGarzon1
AIRCRAFT GENERAL
The Single Aisle is the most advanced family aircraft in service today, with fly-by-wire flight controls.
The A318, A319, A320 and A321 are twin-engine subsonic medium range aircraft.
The family offers a choice of engines
The study of semiconductor layer effect on underground cables with Time Domain Reflectometry (TDR)
1. IOSR Journal of Electrical and Electronics Engineering (IOSR-JEEE)
e-ISSN: 2278-1676,p-ISSN: 2320-3331, Volume 7, Issue 6 (Sep. - Oct. 2013), PP 01-07
www.iosrjournals.org
www.iosrjournals.org 1 | Page
The study of semiconductor layer effect on underground cables
with Time Domain Reflectometry (TDR)
Rodrigo Paludo1
, Guilherme Cunha da Silva2
, Vitoldo Swinka Filho3
1,2and 3
(Department of Materials, Universidade Federal do Paraná, Brasil)
Abstract: Time Domain Reflectometry is a technique used for fault location and partial discharge analysis in
underground electric distribution cables. The technique is based on the analysis of the propagation of short
electric pulses. In underground cables, semiconductor layer properties and degradation cause perturbations in
the signal wave shape. These perturbations complicate the interpretation of reflectograms and, as a
consequence, fault location. This work presents a circuit model of distributed elements that includes the
electrical resistance of the semiconductor layers. The results of computer simulations using the proposed model
are compared with measurements in new and aged XLPE cables. This comparison shows that the proposed
model can represent the phenomena satisfactorily.
Keywords : Underground cables, Simulation of Time Domain Reflectometry, Attenuation spectrum.
I. INTRODUCTION
Rapid fault localization in underground cables reduces grid maintenance time and, as a consequence,
reduces service interruption time. In this context, Time Domain Reflectometry (TDR) is an appropriate
technique to quickly find a fault by analyzing the behavior of short electric pulses propagating in the cable. The
electrical pulses propagate along the cable and can be absorbed or reflected as a result of changes in the
characteristic impedance [1].
Measurements in aged cables show changes in the pulse behavior that make TDR analysis difficult.
In this work, the semiconductor layer’s electric resistance is considered in explaining the pulse attenuation and
dispersion during propagation in new and aged cables, using cable measurements and computational
simulations.
II. MATERIALS AND METHODS
The comparison was performed using XLPE (cross-linked polyethylene) insulated cables, both new
and aged, whose characteristics are shown in Table 1. The cable labeled XLPE-A was manufactured in the
1970s and was removed from operation. The cable labeled XLPE-N is a new cable that has not been used in
operation.
Table 1 – Cable characteristics.
Cables XLPE-N (new) XLPE-A (aged)
Internal diameter (conductor) 8 mm 9 mm
External diameter (insulation) 17.5 mm 19 mm
Internal semiconductor layer thickness 1.2 mm 0.6 mm
External semiconductor layer thickness 1.5 mm 0.5 mm
Characteristic Impedance 33 Ω 36 Ω
Cable length 67 m 33 m
Material of the internal conductor Aluminum
Aluminum conductivity 6
106.59 x 1
m
Dielectric XLPE
XLPE conductivity 15
10
1
m
XLPE relative permittivity 2.4
Voltage class 12/20 kV
Vacuum magnetic permeability 7
104
x ATm/
Relative magnetic permeability of the conductor 1
Vacuum electric permittivity 12
1085.8
x 22
/ NmC
Frequency 25 MHz
To perform TDR, an oscilloscope was used with an acquisition rate of 1 GS/s, and the pulses were generated
with a digital function generator. Fig. 1 shows the classic model of a distributed circuit element [2, 3].
2. The study of semiconductor layer effect on underground cables with Time Domain Reflectometry
www.iosrjournals.org 2 | Page
Figure 1 – Classic model of a distributed element.
The electrical characteristics for a coaxial line are given by [2, 3]:
ba
R
R s 11
.2
'
(1)
where
'R → Resistance per unit length [ m/ ];
'L → Inductance per unit length [ mH / ];
'G → Conductance per unit length [ mS / ];
'C → Capacitance per unit length [ mF / ];
a → Internal conductor radius [m];
b → External conductor radius [m];
→ Dielectric magnetic permeability [ AmT /. ];
→ Dielectric conductivity [ 1
.
m ]; and
→ Dielectric electric permittivity [ 22
./ mNC ].
a
b
L ln
2
'
(2)
a
b
G
ln
2
'
(3)
a
b
C
ln
2
'
(4)
The resistance per unit length of the cable is determined using the intrinsic resistance (Rs), i.e., the skin
resistance of the conductor [2, 3],
c
c
s
f
R
..
(5)
where
f → Frequency [ Hz ];
c → Conductor magnetic permeability [ AmT /. ]; and
c → Conductor conductivity [ 1
.
m ].
III. RESULTS AND DISCUSSION
The Fig. 2 shows the schematic diagram of the experimental setup for TDR.
Figure 2 – Experimental layout for TDR.
Channel 2 from the oscilloscope was connected to the far end of the cable.
3.1 XLPE-N Cable
Using the values from Table 1 and equations (1 - 5), the values of the parameters per unit of cable
length were obtained and are shown in Table 2.
Table 2 – Parameter values of the XLPE-N cable.
Parameters of the cable Values Units
R’ 2
1027.7
x Ω / m
L’ 7
1073.1
x H / m
C’ 10
1054.1
x F / m
G’ 15
1026.7
x S / m
Fig. 3 shows the circuit diagram for the XLPE-N cable where two elements were used for one meter of length.
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Figure 3 – Schematic circuit showing an element used in the simulation of the XLPE-N cable.
The characteristic impedance of the cable is calculated using equation (6) [3], and the value obtained is used to
link the impedance of the function generator with the cable.
''
''
0
jwCG
jwLR
Z
(6) )045.042.33(0 jZ
Fig. 4 shows the result of the simulation for the XLPE-N cable with an open far end.
Figure 4 – Simulation reflectogram of the XLPE-N cable with an open far end.
Fig. 5 shows the reflectogram of the XLPE-N cable measured in the laboratory. Comparing Fig. 5 with Fig. 4,
the agreement between the simulation and lab measurements can be observed.
Figure 5 – Experimental reflectogram of the XLPE-N cable with an open far end.
Fig. 6 shows the results of a simulation with the far end short circuited, where the reflected pulse presents a
negative polarity.
Figure 6 – Simulation reflectogram of the XLPE-N cable in short circuit.
The experimentally obtained reflectogram with the cable in short circuit is shown in Fig. 7.
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Figure 7 – Experimental reflectogram of the XLPE-N cable in short circuit.
Comparing the simulated and experimental graphs, it can be observed that the simulation results are consistent
with the data obtained experimentally from the XLPE-N cable.
3.2. XLPE-A Cable
The same procedure used for the XLPE-N cable was adopted for the XLPE-A cable. The values of the
calculated parameters per unit length of cable are presented in Table 3.
Table 3 – Parameters values of cable XLPE-A.
Parameters of cable Values Units
R’ 2
1033.6
x Ω / m
L’ 7
1087.1
x H / m
C’ 10
1042.1
x F / m
G’ 15
1069.6
x S / m
The circuit diagram for the XLPE-A cable is shown in Fig. 8, where two elements were used for one meter of
length.
Figure 8 – Schematic circuit showing an element used in the simulation of the XLPE-A cable.
The value of the characteristic impedance [4] that was calculated for the aged cable is:
)0409.028.36(0 jZ
Fig. 9 shows the simulated reflectogram of the XLPE-A cable in an open circuit.
Figure 9 – Simulation reflectogram of the XLPE-A cable in open far end.
Fig. 10 shows the reflectogram of the XLPE-A cable obtained with the same arrangement as the reflectogram
presented in Figure 5. In this case, the simulated and experimental reflectograms do not agree, unlike with the
XLPE-N cable.
The velocity of pulse propagation in the XLPE-A cable was calculated using equation (7) [4, 5], giving a value
of sm /195 .
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.
1
pv (7)
With this value of the velocity, the pulse should be observed at the far end of the cable with ns169 of delay,
shown by an arrow in Fig. 10.
Figure 10 – Experimental reflectogram of the XLPE-A cable with an open far end.
Because the theory for transmission lines [6, 7] was applied equally to the two kinds of the cables (new and
aged), the reflectograms should have the same waveform. However, Fig. 9 and Fig. 10 show that the measured
behavior of the cable disagrees with that predicted by the classical model of distributed elements. Therefore,
work was directed toward explaining this phenomenon.
IV. MODEL OF DISTRIBUTED ELEMENTS PROPOSED
The first hypothesis to explain the observed phenomenon in the aged cable was related to the resistivity
of the semiconductor layers and the conductance of the dielectric. The comparison value of resistivity in Table
4, between aged (XLPE-A1 and XLPE-A2) and new (XLPE-N) cables, show that for outer layer the orders of
magnitude are equal. For the inner layer the aged cable show lower value than the new cable and however this
hypothesis was discarded.
Table 4 – Values of resistivity measure.
Semiconductor layer XLPE-A1 XLPE-A2 XLPE-N
Inner 5.21 x 10-3
3.77 x10-3
3.94 x 10-1
Outer 2.77 x 10-2
2.3 x 10-2
5.18 x 10-2
The hypothesis of change in the electrical conductance was evaluated by simulation using values in the range of
10-15
S to 10-3
S and this change was not able to explain the effect of the Fig. 10. A new model was proposed in
which the semiconductor layers are represented by resistances iR (resistance of inner semiconductor layer) and
oR (resistance of outer semiconductor layer) connected in series with the capacitance and conductance of the
distributed-element model, as shown in Fig. 11. In this proposed model, the hypothesis states that there are
mechanisms in the semiconductor layers that are activated by the aging of the cable, and this can change the
way that the pulses propagate in the cable. These changes make the cables become dissipative and dispersive [7,
11].
The waveform signal, shown in Fig. 10, was used as a measure to relate the simulations to a resistance value that
is appropriate for the representation of the semiconductor layers.
The simulated resistance )( oi RR was varied from 20 Ω to 1 kΩ to find a value where the simulated
reflectogram matched the experimental reflectogram in Fig. 10.
As the value of the resistance was increased, the simulated reflectogram more closely approximated the
experimental reflectogram.
Figure 11 – Schematic drawing of the classical model and the proposed model.
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The criterion used for selecting a value of resistance was to compare the ratio of the amplitudes of input pulse
with the far end pulse. As the reflectogram in Fig. 10 shows, the rate is approximately 3.5 times, and this value
was taken as a reference. The resistance value that produced the simulation results closest to the experimental
results for the XLPE-A cable was 100 Ω.
Figure 12 – Simulated reflectogram of an XLPE-A cable with an open far end proposed model and a
semiconductor layer resistance of 100 Ω.
The resistivity measurements of the semiconductor layers showed that the intrinsic resistance of the XLPE-A
cable is not responsible for the change in the waveform. This phenomenon, shown in fig. 10, was attributed to
the coupling of the electrical resistance of the semiconductor layers with other parts of the cable.
In cables that are more than 25 years old, there are regions of oxidation in the semiconductor layers (outer and
inner), which can be observed in Fig. 13.
Figure 13 – XLPE cables (aged on the left and new on the right).
It was observed that the tape in the semiconductor layer of the XLPE-A cable has a low intrinsic resistance
value per meter; however, the layer is positioned between the electromagnetic shielding and the dielectric. This
layer undergoes an increase in coupling resistance due to oxidation caused by the humidity that occur during the
cable’s lifetime. This oxidation is not observed in the new cable.
The energy dissipation factor of the pulse was studied using simulations with different values of resistance
representing the semiconductor layers of the cable. This study was performed by comparing the ratio between
the energy of a pulse position of the cable and the pulse energy injected into the cable. The results of this study
are shown in Fig. 14.
Figure 14 – Comparison of the attenuation along the cable with different resistance values.
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In Fig. 14, it can be observed that the ratio E/E0 decreases with increasing semiconductor layer resistance. The
dissipative behavior for different cable lengths is shown in Fig. 15. This graph was obtained by simulating the
proposed model of the cable with the electrical resistance of the semiconductor layers equal to 100 Ω. The graph
shows the spectrum of attenuation, which is a characteristic of the cable.
Figure 15 – Attenuation spectrum simulated for a cable with semiconductor layer resistance of 100 Ω.
What can be concluded from the attenuation spectrum of the cable, from 100 kHz to 10 MHz, is that as the
length of the cable increases, the value of the cutoff frequency decreases. For example, at 10 meters from the
beginning of the cable, the cutoff frequency is approximately 10 MHz, while at 100 meters from the beginning
of the cable, the cutoff frequency decreases to approximately 5 MHz. Therefore, it can be observed that the
attenuation constant of the cable is related to the pulse frequency.
V. CONCLUSION
The results of the reflectometry performed on aged cable did not agree with the simulation results using
the classical model of distributed elements.
The proposed model produces better agreement with the results of reflectometry that were obtained
from the aged cables. The proposed model introduces a resistance to represent the semiconductor layers at the
inner and outer surfaces of the XPLE dielectric. This resistance can be associated with the degradation
mechanisms in these layers.
The results of the calculations of the resistance per unit length of material from the semiconductor
layers, which was performed using the results of the measured electric resistivity, show that although the values
of resistance are small, they have a significant contribution in this phenomenon. Predominantly, the resistance is
caused by the mechanisms of degradation, such as oxidation. This is confirmed by the results of simulations and
reflectometry made on the new cable, which does not show the dispersive behavior.
The results of simulations with the proposed model showed that the attenuation increases proportionally with the
resistance presented by the semiconductor layers and the degradation mechanisms. Additionally, it was observed
that the attenuation is a function of frequency, which does not occur in the classical model.
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