1) The document analyzes the stress distribution and effect of voids with different gases in MV power cables through finite element modeling. It studies the electric field and temperature distribution within cable insulation containing voids.
2) Cylindrical voids are found to have higher electric stress than spherical or elliptical voids. Among gases, oxygen consumption during partial discharge causes greater temperature rise and faster breakdown than nitrogen.
3) The analysis examines factors like void shape, position, and size that influence stress distribution and partial discharge inception voltage. Nearer and larger voids have lower inception voltages. Oxygen consumption leads to uniform erosion and higher temperatures, making its effect greater than other gases.
Design and Simulation of a Fractal Micro-TransformerIJERA Editor
Due to advancement in smart technologies, the issues like renewable energy integrations into the existing power
systems, reduced weight and size of power equipments is required. In this regard, this work is focused on the
study and design of fractal type micro-transformer for day-to-day applications. An air core transformer is
designed using finite element modeling. The obtained results showed far better implementation parameters in
comparison to the macro transformers.
Deterioration of short channel effectsijistjournal
In the proposed work, the analytical model for Surface potential and Electric field has been carried out in a
novel structure named dual halo triple material Surrounding-gate metal-oxide-semiconductor field effect
transistor (DHTMSG). The new device has been incorporated with symmetrical dual halo regions near
source and drain ends, while the gate terminal consists of three different metals with different work
functions. The results prove that the device significantly deteriorates the short channel effects which are
studied by analytical model for surface potential and electric field using parabolic approximation method.
The analytical results are endorsed by the simulation results.
Iron losses in ferromagnetic enclosures of gas-insulated transmission lines u...Power System Operation
The enclosure of AC gas-insulated transmission lines
(AC-GIL) is ordinarily made of aluminium. In HVDC
systems, it can be economically and technically
reasonable to manufacture the enclosure of GIL from
steel. To check the feasibility to operate such DC-GIL
even under AC the relevant losses in the steel enclosure
must be known.
The present paper compares three different methods to
determine the specific iron losses of steel when exposed
to magnetic fields with power frequencies. The iron
losses as a function of the magnetic field strength are
measured with a pipe sample in a coaxial conductor
arrangement, a pipe sample in a toroidal core test and
with relevant strips in an Epstein frame. The results
from the three test methods are found to be in close
agreement. By calculating the iron losses in a GIL with
steel enclosure the reduction of the transmission capacity
is estimated when changing from DC to AC operation.
To perform geological exploration by the geophysical method of electrical resistivity.
The objective of this research is to evaluate the water potential of the study area by investigating the shallow subsurface aquifer material properties and moisture distribution using 2D ERT techniques. During the shallow tube well design and development in the study area, some patches of land does have good potential and some does not, which motivated to understand the aquifer properties, aquifer material, and response. Hence the 2D ERT was carried out, oriented around the pond in the center and five ERT profiles.
ANALYSIS OF SMALL-SIGNAL PARAMETERS OF 2-D MODFET WITH POLARIZATION EFFECTS F...VLSICS Design
An improved analytical two dimensional (2-D) model for AlGaN/GaN modulation doped field effect
transistor (MODFET) has been developed. The model is based on the solution of 2-D Poisson’s equation.
The model includes the spontaneous and piezoelectric polarization effects. The effects of field dependent
mobility, velocity saturation and parasitic resistances are included in the current voltage characteristics of
the developed two dimensional electron gas (2-DEG) model. The small-signal microwave parameters have
been evaluated to determine the output characteristics, device transconductance and cut-off frequency for
50 nm gate length. The peak transconductance of 165mS/mm and a cut-off frequency of 120 GHz have been
obtained. The results so obtained are in close agreement with experimental data, thereby proving the
validity of the model.
Design and Simulation of a Fractal Micro-TransformerIJERA Editor
Due to advancement in smart technologies, the issues like renewable energy integrations into the existing power
systems, reduced weight and size of power equipments is required. In this regard, this work is focused on the
study and design of fractal type micro-transformer for day-to-day applications. An air core transformer is
designed using finite element modeling. The obtained results showed far better implementation parameters in
comparison to the macro transformers.
Deterioration of short channel effectsijistjournal
In the proposed work, the analytical model for Surface potential and Electric field has been carried out in a
novel structure named dual halo triple material Surrounding-gate metal-oxide-semiconductor field effect
transistor (DHTMSG). The new device has been incorporated with symmetrical dual halo regions near
source and drain ends, while the gate terminal consists of three different metals with different work
functions. The results prove that the device significantly deteriorates the short channel effects which are
studied by analytical model for surface potential and electric field using parabolic approximation method.
The analytical results are endorsed by the simulation results.
Iron losses in ferromagnetic enclosures of gas-insulated transmission lines u...Power System Operation
The enclosure of AC gas-insulated transmission lines
(AC-GIL) is ordinarily made of aluminium. In HVDC
systems, it can be economically and technically
reasonable to manufacture the enclosure of GIL from
steel. To check the feasibility to operate such DC-GIL
even under AC the relevant losses in the steel enclosure
must be known.
The present paper compares three different methods to
determine the specific iron losses of steel when exposed
to magnetic fields with power frequencies. The iron
losses as a function of the magnetic field strength are
measured with a pipe sample in a coaxial conductor
arrangement, a pipe sample in a toroidal core test and
with relevant strips in an Epstein frame. The results
from the three test methods are found to be in close
agreement. By calculating the iron losses in a GIL with
steel enclosure the reduction of the transmission capacity
is estimated when changing from DC to AC operation.
To perform geological exploration by the geophysical method of electrical resistivity.
The objective of this research is to evaluate the water potential of the study area by investigating the shallow subsurface aquifer material properties and moisture distribution using 2D ERT techniques. During the shallow tube well design and development in the study area, some patches of land does have good potential and some does not, which motivated to understand the aquifer properties, aquifer material, and response. Hence the 2D ERT was carried out, oriented around the pond in the center and five ERT profiles.
ANALYSIS OF SMALL-SIGNAL PARAMETERS OF 2-D MODFET WITH POLARIZATION EFFECTS F...VLSICS Design
An improved analytical two dimensional (2-D) model for AlGaN/GaN modulation doped field effect
transistor (MODFET) has been developed. The model is based on the solution of 2-D Poisson’s equation.
The model includes the spontaneous and piezoelectric polarization effects. The effects of field dependent
mobility, velocity saturation and parasitic resistances are included in the current voltage characteristics of
the developed two dimensional electron gas (2-DEG) model. The small-signal microwave parameters have
been evaluated to determine the output characteristics, device transconductance and cut-off frequency for
50 nm gate length. The peak transconductance of 165mS/mm and a cut-off frequency of 120 GHz have been
obtained. The results so obtained are in close agreement with experimental data, thereby proving the
validity of the model.
Effect of mesh grid structure in reducing hot carrier effect of nmos device s...ijcsa
This paper presents the critical effect of mesh grid that should be considered during process and device
simulation using modern TCAD tools in order to develop and optimize their accurate electrical
characteristics. Here, the computational modelling process of developing the NMOS device structure is
performed in Athena and Atlas. The effect of Mesh grid on net doping profile, n++, and LDD sheet
resistance that could link to unwanted “Hot Carrier Effect” were investigated by varying the device grid
resolution in both directions. It is found that y-grid give more profound effect in the doping concentration,
the junction depth formation and the value of threshold voltage during simulation. Optimized mesh grid is
obtained and tested for more accurate and faster simulation. Process parameter (such as oxide thicknesses
and Sheet resistance) as well as Device Parameter (such as linear gain “beta” and SPICE level 3 mobility
roll-off parameter “ Theta”) are extracted and investigated for further different applications.
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.
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.
Space charges analysis on insulator with uniform layer contamination effectTELKOMNIKA JOURNAL
High voltage direct current (HVDC) transmission provides an attractive alternative for bulk power transfer. However, HVDC transmission may have loss about half per unit length of high voltage alternating current (HVAC) at the same amount of power carried. This is due to the space charge formation around the conductor in HVDC cables. It is known that the presence of space charge inside an insulator may distort the local electric field and surface energy. This paper investigates the effect of electrostatics for space charge, electric field and surface energy in the HVDC cable in clean and contaminated conditions. The effect of uniform layer contamination from oil, sandstone and fresh water was conducted on 11 kV XLPE cable using finite element software under electrostatics study. The contamination layer was created around the XLPE cable by multifarious the radius of layer contamination from the conductor. The simulation results show that enlargement of contamination layer radius by 1.0 mm (light), 1.5 mm (medium) and 2.0 mm (heavy) resulted in the reduction of surface energy by 20% and electric field by 22% but increase the space charge amplitude by 76%. The study also found that fresh water can be considered as the worst contamination compared to oil and sandstone.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
Analytic Estimation of Two-Dimensional Electron Gas Density and Current-Volta...IJECEIAES
This paper is mainly dedicated to understand the phenomena governing the formation of two-dimensional electron gas (2DEG) confined in the quantum well which hold the role of the channel in the high electron density transistors (HEMT) based on AlGaN / GaN heterojunction. The theory takes into account: the crystal structure, the spontaneous and piezoelectric polarization concept, the formation mechanism of two-dimensional electron gas at the AlGaN / GaN interface, the approximate resolution of the Poisson and Schrödinger equations to determine the density of Two-dimensional electron gas after the analytical formula of the current-voltage characteristic is established. Our study is also concerned with the dependence of the twodimensional electron gas density on the following technological parameters: Aluminum molare fraction, AlGaN layer thickness and AlGaN layer doping, In order to control the influence of these parameters on the device performance. Finally, the current-voltage characteristic which reflects the variation of the drain-source current as a function of the modulation of the gate voltage has been discussed.
Design of Integrated LC Filter Using Multilayer Flexible Ferrite Sheets iosrjce
Dielectric and magnetic materials were developed for use as integrated passive component design.
The integrated LC component to be investigated in this paper uses ferrite material which combines both
magnetic and dielectric properties. Because of this double property, the ferrite sheet will be used in this design
as magnetic core for the inductor and dielectric substrate for the capacitor. The fabrication is simplified by
using PCB inductor and adhesive flexible ferrite sheet. To evaluate the inductance, the capacitance including
the parasitic resistance, a fabricated prototype of the LC component was simulated and measured. It was
confirmed that simulated values were very close to the measured values and the integrated LC component
behaves as low-pass filter
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
Effect of mesh grid structure in reducing hot carrier effect of nmos device s...ijcsa
This paper presents the critical effect of mesh grid that should be considered during process and device
simulation using modern TCAD tools in order to develop and optimize their accurate electrical
characteristics. Here, the computational modelling process of developing the NMOS device structure is
performed in Athena and Atlas. The effect of Mesh grid on net doping profile, n++, and LDD sheet
resistance that could link to unwanted “Hot Carrier Effect” were investigated by varying the device grid
resolution in both directions. It is found that y-grid give more profound effect in the doping concentration,
the junction depth formation and the value of threshold voltage during simulation. Optimized mesh grid is
obtained and tested for more accurate and faster simulation. Process parameter (such as oxide thicknesses
and Sheet resistance) as well as Device Parameter (such as linear gain “beta” and SPICE level 3 mobility
roll-off parameter “ Theta”) are extracted and investigated for further different applications.
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.
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.
Space charges analysis on insulator with uniform layer contamination effectTELKOMNIKA JOURNAL
High voltage direct current (HVDC) transmission provides an attractive alternative for bulk power transfer. However, HVDC transmission may have loss about half per unit length of high voltage alternating current (HVAC) at the same amount of power carried. This is due to the space charge formation around the conductor in HVDC cables. It is known that the presence of space charge inside an insulator may distort the local electric field and surface energy. This paper investigates the effect of electrostatics for space charge, electric field and surface energy in the HVDC cable in clean and contaminated conditions. The effect of uniform layer contamination from oil, sandstone and fresh water was conducted on 11 kV XLPE cable using finite element software under electrostatics study. The contamination layer was created around the XLPE cable by multifarious the radius of layer contamination from the conductor. The simulation results show that enlargement of contamination layer radius by 1.0 mm (light), 1.5 mm (medium) and 2.0 mm (heavy) resulted in the reduction of surface energy by 20% and electric field by 22% but increase the space charge amplitude by 76%. The study also found that fresh water can be considered as the worst contamination compared to oil and sandstone.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
Analytic Estimation of Two-Dimensional Electron Gas Density and Current-Volta...IJECEIAES
This paper is mainly dedicated to understand the phenomena governing the formation of two-dimensional electron gas (2DEG) confined in the quantum well which hold the role of the channel in the high electron density transistors (HEMT) based on AlGaN / GaN heterojunction. The theory takes into account: the crystal structure, the spontaneous and piezoelectric polarization concept, the formation mechanism of two-dimensional electron gas at the AlGaN / GaN interface, the approximate resolution of the Poisson and Schrödinger equations to determine the density of Two-dimensional electron gas after the analytical formula of the current-voltage characteristic is established. Our study is also concerned with the dependence of the twodimensional electron gas density on the following technological parameters: Aluminum molare fraction, AlGaN layer thickness and AlGaN layer doping, In order to control the influence of these parameters on the device performance. Finally, the current-voltage characteristic which reflects the variation of the drain-source current as a function of the modulation of the gate voltage has been discussed.
Design of Integrated LC Filter Using Multilayer Flexible Ferrite Sheets iosrjce
Dielectric and magnetic materials were developed for use as integrated passive component design.
The integrated LC component to be investigated in this paper uses ferrite material which combines both
magnetic and dielectric properties. Because of this double property, the ferrite sheet will be used in this design
as magnetic core for the inductor and dielectric substrate for the capacitor. The fabrication is simplified by
using PCB inductor and adhesive flexible ferrite sheet. To evaluate the inductance, the capacitance including
the parasitic resistance, a fabricated prototype of the LC component was simulated and measured. It was
confirmed that simulated values were very close to the measured values and the integrated LC component
behaves as low-pass filter
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
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.
Design and modeling of solenoid inductor integrated with FeNiCo in high frequ...TELKOMNIKA JOURNAL
In this work, the design and modeling of the solenoid inductor are discussed. The layout of integrated inductors with magnetic cores and their geometrical parameters are developed. The quality factor Q and inductance value L are derived from the S-parameters and plotted versus frequency. The effect of solenoid inductor geometry on inductance and quality factor are studied via simulation using MATLAB. The solenoid inductor geometry parameters considered are the turn’s number, the magnetic core length, the width of a magnetic core, the gap between turns, the magnetic core thickness, the coil thickness, and solenoid inductor oxide thickness. The performance of the proposed solenoid inductor integrated with FeNiCo is compared with other solenoid inductors.
A Hybrid Model to Predict Electron and Ion Distributions in Entire Interelect...Fa-Gung Fan
Atmospheric direct current (dc) corona discharge
from thin wires or sharp needles has been widely used as an ion
source in many devices such as photocopiers, laser printers, and
electronic air cleaners. Existing numerical models to predict the
electron distribution in the corona plasma are based on charge
continuity equations and the simplified Boltzmann equation. In
this paper, negative dc corona discharges produced from a thin
wire in dry air are modeled using a hybrid model of modified
particle-in-cell plus Monte Carlo collision (PIC-MCC) and a
continuum approach. The PIC-MCC model predicts densities of
charge carriers and electron kinetic energy distributions in the
plasma region, while the continuum model predicts the densities of
charge carriers in the unipolar ion region. Results from the hybrid
model are compared with those from prior continuum models.
Superior to the prior continuum model, the hybrid model is able
to predict the voltage–current curve of corona discharges. The
PIC-MCC simulation results also suggest the validity of the local
approximation used to solve the Boltzmann equation in the prior
continuum model.
Modeling the Dependence of Power Diode on Temperature and RadiationIJPEDS-IAES
A theoretical study had been carried out on the effect of radiation on the
electrical properties of silicon power diodes. Computer program
"PDRAD2015" was developed to solve the diode equations and to
introduce the operating conditions and radiation effects upon its
parameters. Temperature increase interrupts the electrical properties of the
diode in the direction of drop voltage decrease across the p-n junction. The
model was analyzed under the influence of different radiation type (gammarays,
neutrons, protons and electrons) with various dose levels and
energies. The carrier’s diffusion lengths were seriously affected leading
to a large increase in the forward voltage. These effects were found to be
function of radiation type, fluence and energy.
Characterization of silicon tunnel field effect transistor based on charge pl...IJEECSIAES
The aim of the proposed paper is an analytical model and realization of the characteristics for tunnel field-effect transistor (TFET) based on charge plasma (CP). One of the most applications of the TFET device which operates based on CP technique is the biosensor. CP-TFET is to be used as an effective device to detect the uncharged molecules of the bio-sample solution. Charge plasma is one of some techniques that recently invited to induce charge carriers inside the devices. In this proposed paper we use a high work function in the source (ϕ=5.93 eV) to induce hole charges and we use a lower work function in drain (ϕ=3.90 eV) to induce electron charges. Many electrical characterizations in this paper are considered to study the performance of this device like a current drain (ID) versus voltage gate (Vgs), ION/IOFF ratio, threshold voltage (VT) transconductance (gm), and subthreshold swing (SS). The signification of this paper comes into view enhancement the performance of the device. Results show that high dielectric (K=12), oxide thickness (Tox=1 nm), channel length (Lch=42 nm), and higher work function for the gate (ϕ=4.5 eV) tend to best charge plasma silicon tunnel field-effect transistor characterization.
haracterization of silicon tunnel field effect transistor based on charge plasmanooriasukmaningtyas
The aim of the proposed paper is an analytical model and realization of the characteristics for tunnel field-effect transistor (TFET) based on charge plasma (CP). One of the most applications of the TFET device which operates based on CP technique is the biosensor. CP-TFET is to be used as an effective device to detect the uncharged molecules of the bio-sample solution. Charge plasma is one of some techniques that recently invited to induce charge carriers inside the devices. In this proposed paper we use a high work function in the source (ϕ=5.93 eV) to induce hole charges and we use a lower work function in drain (ϕ=3.90 eV) to induce electron charges. Many electrical characterizations in this paper are considered to study the performance of this device like a current drain (ID) versus voltage gate (Vgs), ION/IOFF ratio, threshold voltage (VT) transconductance (gm), and sub-threshold swing (SS). The signification of this paper comes into view enhancement the performance of the device. Results show that high dielectric (K=12), oxide thickness (Tox=1 nm), channel length (Lch=42 nm), and higher work function for the gate (ϕ=4.5 eV) tend to best charge plasma silicon tunnel field-effect transistor characterization.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
Analysis of Electric Field and Current Density on XLPE Insulator IJECEIAES
Good condition and size of the insulator are important to ensure the excellent electric field and current density performance because of aging and degradation HVDC cable problem. At present, the existing insulator which is XLPE insulator that had been used does not meet the capabilities criteria of HVDC cable due to the problem in terms of the condition of the insulator which is the presence of a void in the insulator. A research had been made with Quickfield Software to calculate the electric field and current density in the XLPE insulator of HVDC cable. A void is created in the XLPE insulator by using Quickfield Software by varying diameter of void and distance of void from conductor. XLPE insulator is taken as main research object. The results show that largest diameter of void and nearest distance of void from conductor distorts highest electric field and lowest current density. Therefore, it is important to study both electric field and current density to ensure good capabilities and safety of HVDC cable.
An Analytical Model for Fringing Capacitance in Double gate Hetero Tunnel FET...VLSICS Design
In this paper fringe capacitance of double hetero gate Tunnel FET has been studied. The physical model for fringe capacitance is derived considering source gate overlap and gate drain non overlap. Inerface trap charge and oxide charges are also introduced under positive bias stress and hot carrier stress and their effect on fringe capacitance is also studied. The fringe capacitance is significant speed limiter in Double gate technology. The model is tested by comparing with simulation results obtained from Sentauras TCAD simulations.
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.
Analysis Of 3C-Sic Double Implanted MOSFET With Gaussian Profile Doping In Th...IJRES Journal
The present work aims at the design of 3C-SiC Double Implanted Metal Oxide Semiconductor Field Effect Transistor (DIMOSFET) with Gaussian doping profile in drift region for high breakdown voltages. By varying the device height ‘h’, function constant m and peak concentration 𝑁0, analysis has been done for an optimum profile for high breakdown voltage. With Gaussian profile peak concentration 𝑁0 = 1016 𝑐𝑚−3 at drain end and m as 1.496 ×10−2cm, highest breakdown voltage of 6.84kV has been estimated with device height of 200μm.
Similar to Some Aspects of Stress Distribution and Effect of Voids Having Different Gases in MV Power Cables (20)
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.
NO1 Uk best vashikaran specialist in delhi vashikaran baba near me online vas...Amil Baba Dawood bangali
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Sachpazis:Terzaghi Bearing Capacity Estimation in simple terms with Calculati...Dr.Costas Sachpazis
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TECHNICAL TRAINING MANUAL GENERAL FAMILIARIZATION COURSE
Some Aspects of Stress Distribution and Effect of Voids Having Different Gases in MV Power Cables
1. IOSR Journal of Electrical and Electronics Engineering (IOSR-JEEE)
e-ISSN: 2278-1676,p-ISSN: 2320-3331, Volume 5, Issue 6 (May. - Jun. 2013), PP 16-22
www.iosrjournals.org
www.iosrjournals.org 16 | Page
Some Aspects of Stress Distribution and Effect of Voids Having
Different Gases in MV Power Cables
Avinash S, K. Rajagopala
(Department of Electrical & Electronics, National Institute of Technology Karnataka, Surathkal, India)
Abstract : Partial discharge (PD) may have long time delay from days to years depending on the size and
other characteristics of voids under electric stress. Voids may be formed due to expansion and contraction of
the cables. Enlargement of voids is due to chemical reaction by discharge byproducts and continuous
bombardment of particles ( ). The variation in distribution of stress in the void is influenced by the
factors like the size of the void, number of voids along the field distribution, the void orientation, the position of
the void and the insulation thickness. The influence of discharge inception voltage on the shape and the location
of the void are studied. Field variation inside the cavity, the influence of nearby cavities and the comparison of
the various shapes of voids in single and three core cables are studied. The variations in temperature
distribution of various gases are studied. Among the various gases, oxygen and nitrogen plays a bigger role
during PD activity. Oxygen causes uniform erosion in cavity surface by consuming itself in a closed cavity
leaving nitrogen, moisture and other gases to initiate the PD. This will result in faster PD activity than the other
gases. These observations are done in COMSOL multiphysics software which uses Finite Element Method
(FEM) to solve partial differential equations.
Keywords - Partial discharge (PD); Finite element method (FEM); COMSOL multiphysics software; Electric
field stress; Voids.
I. INTRODUCTION
Partial Discharge plays a significant role in breakdown of the cable insulation. The operational stresses
that occur in cable insulation which include thermal, mechanical and electrical effects will vary with time and can
cause degradation due to the resulting physical and chemical changes in cable properties. PD’s are small electrical
discharges produced by local enhancement of the electrical stress. The internal discharge in insulation material
and/or at its interface is caused by the strong and inhomogeneous electrical fields that are usually caused by voids
[1].With the determination of the magnitude of the electric field and its spatial distribution within the cable, it is
possible to set a limit on the voltage rating for a given insulation thickness, or alternatively, for a given voltage
rating the optimum insulation thickness to be used in the construction of cables may be determined. The
insulation thickness is largely based on industrial experience which is built up on a trial and error basis [2]. It is
impossible to produce polymeric insulation without micro-porosity. But even to reduce the size of voids below 50
μm the cost of products will increase during the manufacturing of cables. Under heavy loading conditions, owing
to the large difference of thermal expansion coefficients between the polymeric insulation and a conductor, a
crescent-shaped air gap will be formed between one side of the conductor and its insulation. Such gap will greatly
reduce the partial discharge level of the cable [3].Several types of voids in a power cable are studied. The voids
located in butt-gaps with a lens-shape are the most dangerous one in terms of their PD potential [4]. Expressions
are derived for determining the PD inception voltage in typical voids in cables. Since the ionization and
occurrence of partial discharges within the voids would cause erosion and local deterioration of the insulation,
which leads to a complete failure of the cable, hence the importance is given to knowledge of the conductor
voltage at which partial discharges takes place inside the void [5].The main degradation products were found to
be hydrogen, carbon monoxide, methane and carbon dioxide which are produced in a power cable when exposed
to PD activity. Droplets were formed on the surface of XLPE only when an atmosphere containing water and
carbon monoxide is present. The droplets were found to be a mixture of simple organic compounds, like formic,
acetic and carboxylic acids. If one of the constituents H, C or O is absent no droplets appears [6].
By using FEM, any degree of accuracy is obtained. The finite element method reduces a problem to that of
solving a number of simultaneous algebraic equations. The solution of the equations yields the electric field and
temperature distribution within the area under consideration [1].COMSOL multiphysics has a multiple tools for
all engineering applications, here two modes of applications are used they are namely Electrostatics and Heat
transfer modules. In electrostatics module we model the cable for obtaining the electric field, potential
distribution and heat transfer module we model the cable for obtaining the temperature distribution and heat
transfer through cable. The modeling of cable in electrostatic and thermal model is obtained by using a flow chart
and mesh generation using FEM in COMSOL multiphysics software [7].
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II. ANALYSIS OF ELECTRIC FIELD DISTRIBUTION IN VOIDS
1.1 Cable model
The simplified cable model is shown in Fig. 1. The present work tries to obtain the electric field and
temperature distribution within a XLPE insulated cable containing a void-defect. The finite element model of an
XLPE underground cable containing void-defect is developed using the COMSOL multiphysics.
Figure 1: Simplified Cable Model
The parameters of a cable are taken from Cable Corporation of India Ltd (CCI) [7], to study the electrical
distribution of single core and three core cable with different arrangement [8].
Table. 1: Parameters of a Cable
Layer Diameter (mm) Material Thermal Conductivity
(W/m. 0
c )
Conductor CCI Copper 400
Dielectric CCI Polyethylene 0.2
Metallic sheath CCI Lead 35
1.2 Analysis to demonstrate influence of cylindrical and spherical cavity[4]
Figure 2: Void Located in the Uniform Field of the Cable [4].
Model of a spherical void within the insulation is shown in Fig. 2. The void is assumed to be filled with air
( ). The analytical formulae used here is by assuming there is no free surface change at the insulation
surface and cavity boundary, a cylindrical cavity placed in a uniform dielectric field , with the cavity axis
normal to the direction of , will have electric stress (E(r)) outside and inside the cavity determined by (1)
and (2),
E(r) = ( [1+ ( - / + ) / ] cosθ - [1-( - / + ) / ] sinθ ) for r > a (1)
E(r) = (2 / + ) ( cosθ - sinθ) for 0 ≤ r < a (2)
For a spherical cavity the stress outside and inside the cavity can be calculated by (3) and (4),
E(r) = ( [-1-( - / + ) 2 / ]cosθ + [1-( - / + 2 ) / ]sinθ) for r > a (3)
E(r) = (-( cosθ - sinθ) (3 / + 2 )) for 0 ≤ r < a (4)
Where a = radius of the cavity.
r = distance from the cavity center.
In practical, cavities have irregular shapes & thus analytical solutions for such voids are impossible.
Due to singularity point at the corner of a cylindrical cavity, the analytical method is used with simplifying
assumption. In such cases, FEM is chosen for computation use. It consists of four main parts: the insulation
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material, the conductor material, the cavity and the cavity surface. The cavity itself is subdivided into small
channels which are used for determining the stress distribution inside the cavity.
1.3 Discharge Inception Voltage[5]
Figure 3: Geometrical Configuration of a Cable
Expressions are derived for the discharge inception voltage ( ), at which discharge occurs in voids within the
insulation of single core cables.
Consider a single-core solid cable of conductor radius and insulation thickness T. Let a cavity of thickness
‘t’ be within the insulation and at a distance r' from the conductor center, as shown in Fig. 3. The conductor
voltage V would be given by,
V= dr + dr + dr (5)
Where, and are the electric fields in the dielectric & cavity respectively.
The dielectric field at a distance ‘r’ from conductor center is given by,
= q/ 2π r (6)
Where, q is the charge/unit length of the conductor
is the relative permittivity of the dielectric
Field inside a small spherical cavity in a dielectric is given by,
= (7)
Thus for a spherical cavity (5) becomes,
V= [ + + ] (8)
Then,
V= [ln (1+ ) + ( – 1) ln(1+ )] (9)
The discharge inception voltage is that of the conductor at which the field in the cavity equals the
breakdown strength of the entrained gas which is given by,
= (10)
Hence for the spherical cavity, is given by,
= (2+ ) ln (1+ ) + (1- ) ln ( ) (11)
Where depends on the pressure of gas inside the cavity, type of the gas and the thickness of the cavity.
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Similarly for the case of a cylindrical cavity concentric with the conductor is given by,
= { ln(1+ ) + (1- ) ln (1+ )} (12)
is calculated from (11) and (12) as a function of the cavity thickness ‘t’, for different locations ‘r’ of the
cavity within the insulation & for different geometric parameters ‘ ’ & ‘T’ of the cable.
III. TEMPERATURE DISTRIBUTION DUE TO OXYGEN AND NITROGEN IN VOIDS
Partial discharge is due to the high temperature gas production which causes local temperature rise
resulting in melting of materials. This finally causes breakdown of cables. Nitrogen (N) PD tends to produce
local degradation and it causes micro PD pulses. PD could have very long statistical time lag depending on size
and other characteristics of the voids under thermal stress. The number of initial electrons prior to the first
discharge in a cavity will depend mainly on its space & therefore very small for micro voids in the order of
micrometers in diameter. After the oxygen is consumed, nitrogen is left facilitates the initiation of micro PD.
Oxygen (O) is presumed to be almost all consumed in a closed cavity by PD at its early stage [9].
IV. MODELLING RESULTS
1.4 FIELD DISTRIBUTION DUE TO DIFFERENT SHAPES OF VOIDS
FIGURE 4: ELECTRICAL FIELD DISTRIBUTION OF SPHERICAL AND ELLIPTICAL SHAPES OF VOIDS IN A SINGLE CORE
CABLE
Figure 5: Variation of Electric Field in Spherical Void Figure 6: Variation of Electric Field in Elliptical Void
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Fi
gure 7: 3D plot of Potential Distribution in Two Core Figure 8: 3D plot of Field Distribution in Three Core
Cable with Spherical and Cylindrical Voids Cables with Voids
1.5 FIELD DISTRIBUTION WITH VOIDS IN VARIOUS POSITIONS IN A CABLE
FIGURE 9: 3D PLOT OF A TWO CORE CABLE WITH FIGURE 10: FIELD DISTRIBUTION IN TWO CORE
CABLE VOID AT THE CONDUCTOR WITH A VOID IN THE DIELECTRIC
FIGURE 11: VARIATION OF ELECTRIC FIELD AT VOIDS FIGURE 12: VARIATION OF ELECTRIC FIELD AT
VOIDS IN THE DIELECTRIC IN TWO CORE CABLE AT THE SHEATH IN A SINGLE CORE CABLE
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1.6 FIELD DISTRIBUTION OF VOIDS IN VARIOUS POSITIONS OF A CABLE
FIGURE 13: VARIATION OF TOTAL HEAT FLUX IN A CABLE WITH VOIDS
FIGURE 15: VARIATION OF HEAT FLUX FIGURE 14: VARIATION OF HEAT FLUX ON THE
ON THE SURFACE OF VOIDS HAVING NITROGEN SURFACE OF VOIDS HAVING OXYGEN
V. DISCUSSIONS
The electric field distribution in the void is studied by considering different void shapes and positions
of the void. The cylindrical voids will have higher stress than spherical and elliptical voids as shown in Fig. 7.
The electric stress will be high in spherical void than in the elliptical void as shown in Fig. 4, Fig. 5 and Fig. 6.
A 3D plot of field distribution in three core cable with voids is shown in Fig. 8. These observations shows that
from different types of voids in power cables, the voids having lens shape will have more electric stress. The
larger voids have higher stress. The cavity stress increases as the dielectric permittivity increases. The voids
with its axis parallel to the applied field have a higher stress distribution.
is calculated using void thickness ‘t’ for different positions of the spherical voids. The field
distribution of the void near the conductor, at the dielectric and at the sheath is shown in Fig. 9, Fig. 10, Fig. 11
and Fig. 12 respectively. Discharge inception voltage will be smaller when the void is larger and also when the
void is nearer to the conductor.
Variation of total heat flux in a cable with voids which is filled with nitrogen and oxygen separately
is shown in Fig. 13. Nitrogen is partially consumed by chemical reaction to produce nitrogen compounds in the
cavity surface. Partial discharge would takes place with sufficient oxygen. Not only oxygen helps in temperature
rise which is shown by comparing Fig. 14 and Fig. 15, but also helps oxidation. Oxygen would be consumed
completely during PD in a cable and causes temperature rise which results in thermal breakdown of cables.
Therefore oxygen is important than other gases during PD in a cable.
VI. CONCLUSION
It is observed that cylindrical voids have more electric stress than in spherical and elliptical voids.
Among various gases, nitrogen and oxygen plays a significant role during PD. But oxygen consumes completely
causing rise in temperature than the nitrogen in the void leading to thermal breakdown of the cable.
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