samy ghania - Academia.edu (original) (raw)
Papers by samy ghania
Engineering, Technology & Applied Science Research
This paper presents a new evaluation technique for determining the hybridization efficiency of a ... more This paper presents a new evaluation technique for determining the hybridization efficiency of a vehicle. First, the saving in fuel consumption is estimated in the ideal case considering the vehicle runs through a standard driving cycle and the engine runs at the lowest specific fuel consumption all the time. Subsequently, the hybridization efficiency can be defined as the ratio between the fuel savings in hybrid mode to the ideal savings according to the standard driving cycle. A case study was conducted with a medium-size passenger car according to the new European standard driving cycle. The results showed that the new proposed evaluation criterion is very effective for evaluating hybrid vehicles.
Electric power systems with transmission lines play the vital role for ensuring uninterrupted pow... more Electric power systems with transmission lines play the vital role for ensuring uninterrupted power delivery from the generating stations to the load locations. Power Transmission lines outages are relatively high and are exposed to disruptive actions over everyday life. Switching/Lightning Overvoltages for power transmission lines should not cause damage of line insulation or cause unreliable operation of transmission lines. This paper describes investigations on 220 kV transmission line for lightning overvoltage suppression, controlling the switching overvoltages and the line insulation coordination. The selected 220 kV transmission is operated by the Egyptian utility around greater Cairo. The modeled system consists of overhead line, surge arresters and the towers modelling with footing earth resistance. The system has been simulated using (MATLAB/EMTP) software packages. The controllable metal oxide surge arresters are used to act as the main overvoltage protection devices over ...
2016 Eighteenth International Middle East Power Systems Conference (MEPCON), 2016
When a new bug report is received, developers usually need to reproduce the bug and perform code ... more When a new bug report is received, developers usually need to reproduce the bug and perform code reviews to find the cause, a process that can be tedious and time consuming. A tool for ranking all the source files with respect to how likely they are to contain the cause of the bug would enable developers to narrow down their search and improve productivity. This paper introduces an adaptive ranking approach that leverages project knowledge through functional decomposition of source code, API descriptions of library components, the bug-fixing history, the code change history, and the file dependency graph. Given a bug report, the ranking score of each source file is computed as a weighted combination of an array of features, where the weights are trained automatically on previously solved bug reports using a learning-to-rank technique. We evaluate the ranking system on six large scale open source Java projects, using the before-fix version of the project for every bug report. The experimental results show that the learning-to-rank approach outperforms three recent state-of-the-art methods. In particular, our method makes correct recommendations within the top 10 ranked source files for over 70 percent of the bug reports in the Eclipse Platform and Tomcat projects.
2010 Annual Report Conference on Electrical Insulation and Dielectic Phenomena, 2010
With the development of cities and electric power industry, the demand of electrical energy, gene... more With the development of cities and electric power industry, the demand of electrical energy, generation, transmission, distribution and the voltage levels have increased considerably. Therefore the power frequency electric field and environmental impact assessment near / under the high voltage overhead busbars, incoming and outgoing feeders inside the high voltage substations (HVS) have caused wide public concern. Nowadays most research on electric field are concerned with calculation the electric field distribution around the transmission lines, insulators and cables but they rarely concerned with its calculation inside HVS. In this paper, a different type of calculation is achieved, the charge simulation method (CSM) is employed to analyze the three dimensional (3-D) electric field distribution near / under the busbars, incoming and outgoing feeders. At last, the effects of changing the level of operating voltage, the space between the phases, the level of calculation inside HVS is demonstrated.
2011 Annual Report Conference on Electrical Insulation and Dielectric Phenomena, 2011
Finite element analysis (FEA) method was employed to perform three-dimensional (3D) electric fiel... more Finite element analysis (FEA) method was employed to perform three-dimensional (3D) electric field simulations for gas detectors with multiple wire electrodes. A new element refinement method developed for use in conjunction with the FEA program ANSYS allows successful meshing of the wires without physically inputting the wires in the chamber geometry. First, we demonstrate a model with only one wire, for which we calculate the potential distributions on the central plane and the end-cap region. The results are compared to the calculations obtained using GARFIELD, a two-dimensional program that uses the nearly exact boundary element method. Then we extend the method to same model, but with seven wires. Our results suggest that the new method can be applied easily to the 3D electric field calculations for complicated gas detectors with many wires and complicated geometry such as multiwire proportional chambers and time projection chambers.
International Journal of Electrical and Power Engineering, 2011
IEEE Transactions on Power Delivery, 2009
Electromagnetic interference effects of transmission lines on nearby metallic structures such as ... more Electromagnetic interference effects of transmission lines on nearby metallic structures such as pipelines, communication lines, or railroads are a real problem, which can place both operator safety and structure integrity at risk. The level of these voltages can be reduced to a safe value in accordance with the IEEE standard 80 by designing a proper mitigation system. This paper presents a Fuzzy algorithm that can predict the level of the metallic conductor voltage. The model outlined in this paper is both fast and accurate and can accurately predict the voltage magnitude even with changing system parameters (soil resistivity, fault current, separation distance, mitigated or unmitigated system). Simulation results for three different scenarios, confirm the capability of the proposed Fuzzy system model in modeling and predicting the total voltage and are found to be in good agreement with data obtained from the CDEGS software.
Engineering, Technology & Applied Science Research
Reliability analysis is considered an impressive approach for investigating the planning and desi... more Reliability analysis is considered an impressive approach for investigating the planning and design processes of industrial and commercial electrical power distribution systems. Reliability analysis is mainly concerned with the analysis of devices and systems whose individual components are prone to failure risk. The demand for renewable energy resources that work in parallel or replace traditional energy resources is significantly increasing. The current research presents the reliability analysis of the IEEE 40-bus system integrated with large-scale PV and wind systems. Reliability parameters evaluation of power distribution systems will be performed using the zone branch methodology to divide the power system layout into several sections (protected zones). The compensating capacitors will be addressed to clarify their impacts on the system reliability indices. The 40-bus system, known as the IEEE Standard 493-1997, integrated with large-scale PV and wind is simulated using ETAP so...
Electromagnetic interference effects of transmission lines on nearby metallic structures such as ... more Electromagnetic interference effects of transmission lines on nearby metallic structures such as pipelines, communication lines or railroads are a real problem, which can place both operator safety and structure integrity at risk. The level of these voltages can be reduced to a safe value in accordance with the IEEE standard 80 by designing a proper mitigation system. This paper presents a Neural Fuzzy model that can predict the level of the metallic conductor voltage before and after applying a mitigation system. The model outlined in this paper is both fast and accurate and can predict the voltage for any change in the system parameters (soil resistivity, fault current, lateral distance, mitigated or unmitigated system). 1.
The probable risk of electromagnetic fields produced inside high voltage substation is still cons... more The probable risk of electromagnetic fields produced inside high voltage substation is still considered as a competitive topic for utility designers and biomedical field researchers. Hence, the electromagnetic field levels and their induction inside human body should be pre-evaluated as early as the design stage of the substation. This paper deals with the computation of the electromagnetic fields induction in human body inside a typical high voltage 500/220 kV air-insulated substation (AIS). The typical high voltage substation is simulated by developing multi-scripts of m-file Matlab software package to calculate individually both of electric and magnetic fields. Moreover, analytical human body is simulated and allocated within the highly exposure zones of electromagnetic fields. The electromagnetic fields induction inside the human body during live working conditions at different accessible positions is evaluated based on the finite-difference time- domain (FDTD) method for solvin...
The optimized use of the energy stored in induction motors during deceleration is still a competi... more The optimized use of the energy stored in induction motors during deceleration is still a competitive challenge especially for Electrical Vehicles (EV) drive systems designer and manufactures. There are many control algorithms depending on many different methodologies to reach a balance point to determine when exactly the regenerative braking will be used effectively and how long that whether it will be remained usage rather using the normal mechanical braking. The drive system allows the control/conversion of the mechanical energy stored in the EV’s inertial mass to convert the kinetic energy into electric energy. Further benefits of regenerative braking is fuel saving rather than the corresponding internal combustion engine ICE while ramp down/deceleration. This paper presents the simulated model and the concept of the control algorithm used in electrical vehicles. Moreover, it presents the main factors that affect the regenerated power and the optimization of using regenerative b...
Battery Management Systems (BMS) are used in many industrial and commercial systems to make the b... more Battery Management Systems (BMS) are used in many industrial and commercial systems to make the battery operation more efficient and for the estimation to keep the battery state, as long as possible, away from destructive state, to increase battery life time. For this purpose, many monitoring techniques are used to monitor the battery state of charge, temperature and current. In the current paper, the monitoring system for battery powered Electric Vehicles (EV) has been implemented and tested. This system evaluates and displays the battery temperature, charging/discharging current and State Of Charge (SOC) for the considered model battery. For monitoring purpose, digital and analog sensors with microcontrollers are used. The battery information and the obtained results explaining the main characteristics of the system are presented by photographs and some experimental results are given by the LCD screen.
The Journal of Engineering Research, 2016
The probable risk of electromagnetic fields produced inside high voltage substation is still cons... more The probable risk of electromagnetic fields produced inside high voltage substation is still considered as a competitive topic for utility designers and biomedical field researchers. Hence, the electromagnetic field levels and their induction inside human body should be pre-evaluated as early as the design stage of the substation. This paper deals with the computation of the electromagnetic fields inside a typical high voltage 500/220 kV air-insulated substation (AIS). The typical high voltage substation is simulated by developing multi-scripts of m-file Matlab software package to calculate both of electric and magnetic field individually. Moreover, analytical human body is simulated and allocated within the highly exposure zones of electromagnetic fields. The electromagnetic field induction inside the human body during live working conditions at different accessible positions is evaluated based on the power density vector (poynting vector) using the finite-difference time-domain (F...
Lecture Notes in Electrical Engineering, 2019
Traveling wave analysis process over the long High Voltages Direct Current (HVDC) transmission li... more Traveling wave analysis process over the long High Voltages Direct Current (HVDC) transmission lines for internal and external fault surges is rarely tackled and still as a competitive research issue. Transient surges resulting from different internal and external faults may cause sever risk failure to the long HVDC lines. Once, a fault occurs over the HVDC transmission line, high frequency traveling waves (TW) are generated. These traveling waves propagate away from the fault position in both direction of the transmission line with approximately the light speed. During internal faults the traveling waves can be detected at both line terminals. For external faults, the traveling wave can be detected only at one-line terminal with zero at the other terminal. Therefore, the identification method for internal and external fault surges for HVDC lines can be proposed by comparing the amplitude of the traveling waves at both ends of line. In the current paper, analysis has been investigat...
Power system perturbations are due to many reasons; one of the most common perturbation causes is... more Power system perturbations are due to many reasons; one of the most common perturbation causes is switching off/on the power capacitors. This paper monitors and discusses the overvoltages which appear on local and remote capacitor connected buses in power systems. Using the Fast Fourier Transfer (FFT), the total harmonic content of voltages and currents waveforms is also estimated at all buses. The power factor during different cases of switching modes “off/on” is monitored. The monitoring technique tackles not only the longitudinal long distance mutual effects of switching power capacitors between different buses but also evaluates the overvoltage durations. A relative long term monitoring is implemented using the Matlab/Simulink environment to show severity assessments in different switching modes on the transformers’ voltages and currents’ waveforms.
Transformers are major elements of any power systems. Normally they must be properly protected by... more Transformers are major elements of any power systems. Normally they must be properly protected by differential relays. This protection system should be precise and reliable via implementation of strong algorithms that able to differentiate between faulted and unfaulted condition to fully grantee of power continuity. This system should be able to detect the non-faulted condition, such as inrush currents which should not be activated in this condition meanwhile; it must be activated in internal fault conditions as fast as possible. This paper presents an approach for differential protection of power transformers this uses wavelet transform (WT) and adaptive network-based fuzzy inference system (ANFIS) to discriminate internal faults from inrush currents. The proposed algorithm has been designed based on the differences between both amplitudes of wavelet transform coefficients in a specific frequency band and rising and decaying duration generated by faults and inrush currents. The per...
This paper addresses the issue of the interaction of the human body with power frequency (50/60 H... more This paper addresses the issue of the interaction of the human body with power frequency (50/60 Hz) magnetic fields. Two human body models are used; a simple spheroid based on an analytical method and an approximate human shape based on finite element method (FEM). The employed human body models are positioned in two magnetic field sources; under a power transmission line and inside an electric power substation representing typical exposure cases. The magnetically induced currents inside human body due to the exposure to power frequency magnetic fields are evaluated. A number of parameters such as human dimensions and proximity to the current-carrying conductors are considered. A comparative analysis of the magnetic induction inside the human body due to the different human models and magnetic field sources is also presented.
High voltage substations are the main part in any power system utilities or municipalities. Prope... more High voltage substations are the main part in any power system utilities or municipalities. Proper design of lightning protection system should be done in the preliminary stage of the design process. In this paper, a typical high voltage substations of 500/220 kV is modeled by developing multi-scripts of Matlab m-files. To allocate and to simulate the whole carrying current conductors inside the substation and with 100 m length of input and output power lines. This is to calculate and to demonstrate the lightning electromagnetic fields inside the substations during lightning conditions using the Finite Difference Time Domain (FDTD) method with Maxwell’s equations. The effects of the posts allocations, its heights and surge arrestors to secure optimum protection zones are investigated. The electromagnetic fields distribution around the posts and inside the entire area of the substation during lightning conditions are evaluated. The electromagnetic fields for lightning over the input/...
Engineering, Technology & Applied Science Research
This paper presents a new evaluation technique for determining the hybridization efficiency of a ... more This paper presents a new evaluation technique for determining the hybridization efficiency of a vehicle. First, the saving in fuel consumption is estimated in the ideal case considering the vehicle runs through a standard driving cycle and the engine runs at the lowest specific fuel consumption all the time. Subsequently, the hybridization efficiency can be defined as the ratio between the fuel savings in hybrid mode to the ideal savings according to the standard driving cycle. A case study was conducted with a medium-size passenger car according to the new European standard driving cycle. The results showed that the new proposed evaluation criterion is very effective for evaluating hybrid vehicles.
Electric power systems with transmission lines play the vital role for ensuring uninterrupted pow... more Electric power systems with transmission lines play the vital role for ensuring uninterrupted power delivery from the generating stations to the load locations. Power Transmission lines outages are relatively high and are exposed to disruptive actions over everyday life. Switching/Lightning Overvoltages for power transmission lines should not cause damage of line insulation or cause unreliable operation of transmission lines. This paper describes investigations on 220 kV transmission line for lightning overvoltage suppression, controlling the switching overvoltages and the line insulation coordination. The selected 220 kV transmission is operated by the Egyptian utility around greater Cairo. The modeled system consists of overhead line, surge arresters and the towers modelling with footing earth resistance. The system has been simulated using (MATLAB/EMTP) software packages. The controllable metal oxide surge arresters are used to act as the main overvoltage protection devices over ...
2016 Eighteenth International Middle East Power Systems Conference (MEPCON), 2016
When a new bug report is received, developers usually need to reproduce the bug and perform code ... more When a new bug report is received, developers usually need to reproduce the bug and perform code reviews to find the cause, a process that can be tedious and time consuming. A tool for ranking all the source files with respect to how likely they are to contain the cause of the bug would enable developers to narrow down their search and improve productivity. This paper introduces an adaptive ranking approach that leverages project knowledge through functional decomposition of source code, API descriptions of library components, the bug-fixing history, the code change history, and the file dependency graph. Given a bug report, the ranking score of each source file is computed as a weighted combination of an array of features, where the weights are trained automatically on previously solved bug reports using a learning-to-rank technique. We evaluate the ranking system on six large scale open source Java projects, using the before-fix version of the project for every bug report. The experimental results show that the learning-to-rank approach outperforms three recent state-of-the-art methods. In particular, our method makes correct recommendations within the top 10 ranked source files for over 70 percent of the bug reports in the Eclipse Platform and Tomcat projects.
2010 Annual Report Conference on Electrical Insulation and Dielectic Phenomena, 2010
With the development of cities and electric power industry, the demand of electrical energy, gene... more With the development of cities and electric power industry, the demand of electrical energy, generation, transmission, distribution and the voltage levels have increased considerably. Therefore the power frequency electric field and environmental impact assessment near / under the high voltage overhead busbars, incoming and outgoing feeders inside the high voltage substations (HVS) have caused wide public concern. Nowadays most research on electric field are concerned with calculation the electric field distribution around the transmission lines, insulators and cables but they rarely concerned with its calculation inside HVS. In this paper, a different type of calculation is achieved, the charge simulation method (CSM) is employed to analyze the three dimensional (3-D) electric field distribution near / under the busbars, incoming and outgoing feeders. At last, the effects of changing the level of operating voltage, the space between the phases, the level of calculation inside HVS is demonstrated.
2011 Annual Report Conference on Electrical Insulation and Dielectric Phenomena, 2011
Finite element analysis (FEA) method was employed to perform three-dimensional (3D) electric fiel... more Finite element analysis (FEA) method was employed to perform three-dimensional (3D) electric field simulations for gas detectors with multiple wire electrodes. A new element refinement method developed for use in conjunction with the FEA program ANSYS allows successful meshing of the wires without physically inputting the wires in the chamber geometry. First, we demonstrate a model with only one wire, for which we calculate the potential distributions on the central plane and the end-cap region. The results are compared to the calculations obtained using GARFIELD, a two-dimensional program that uses the nearly exact boundary element method. Then we extend the method to same model, but with seven wires. Our results suggest that the new method can be applied easily to the 3D electric field calculations for complicated gas detectors with many wires and complicated geometry such as multiwire proportional chambers and time projection chambers.
International Journal of Electrical and Power Engineering, 2011
IEEE Transactions on Power Delivery, 2009
Electromagnetic interference effects of transmission lines on nearby metallic structures such as ... more Electromagnetic interference effects of transmission lines on nearby metallic structures such as pipelines, communication lines, or railroads are a real problem, which can place both operator safety and structure integrity at risk. The level of these voltages can be reduced to a safe value in accordance with the IEEE standard 80 by designing a proper mitigation system. This paper presents a Fuzzy algorithm that can predict the level of the metallic conductor voltage. The model outlined in this paper is both fast and accurate and can accurately predict the voltage magnitude even with changing system parameters (soil resistivity, fault current, separation distance, mitigated or unmitigated system). Simulation results for three different scenarios, confirm the capability of the proposed Fuzzy system model in modeling and predicting the total voltage and are found to be in good agreement with data obtained from the CDEGS software.
Engineering, Technology & Applied Science Research
Reliability analysis is considered an impressive approach for investigating the planning and desi... more Reliability analysis is considered an impressive approach for investigating the planning and design processes of industrial and commercial electrical power distribution systems. Reliability analysis is mainly concerned with the analysis of devices and systems whose individual components are prone to failure risk. The demand for renewable energy resources that work in parallel or replace traditional energy resources is significantly increasing. The current research presents the reliability analysis of the IEEE 40-bus system integrated with large-scale PV and wind systems. Reliability parameters evaluation of power distribution systems will be performed using the zone branch methodology to divide the power system layout into several sections (protected zones). The compensating capacitors will be addressed to clarify their impacts on the system reliability indices. The 40-bus system, known as the IEEE Standard 493-1997, integrated with large-scale PV and wind is simulated using ETAP so...
Electromagnetic interference effects of transmission lines on nearby metallic structures such as ... more Electromagnetic interference effects of transmission lines on nearby metallic structures such as pipelines, communication lines or railroads are a real problem, which can place both operator safety and structure integrity at risk. The level of these voltages can be reduced to a safe value in accordance with the IEEE standard 80 by designing a proper mitigation system. This paper presents a Neural Fuzzy model that can predict the level of the metallic conductor voltage before and after applying a mitigation system. The model outlined in this paper is both fast and accurate and can predict the voltage for any change in the system parameters (soil resistivity, fault current, lateral distance, mitigated or unmitigated system). 1.
The probable risk of electromagnetic fields produced inside high voltage substation is still cons... more The probable risk of electromagnetic fields produced inside high voltage substation is still considered as a competitive topic for utility designers and biomedical field researchers. Hence, the electromagnetic field levels and their induction inside human body should be pre-evaluated as early as the design stage of the substation. This paper deals with the computation of the electromagnetic fields induction in human body inside a typical high voltage 500/220 kV air-insulated substation (AIS). The typical high voltage substation is simulated by developing multi-scripts of m-file Matlab software package to calculate individually both of electric and magnetic fields. Moreover, analytical human body is simulated and allocated within the highly exposure zones of electromagnetic fields. The electromagnetic fields induction inside the human body during live working conditions at different accessible positions is evaluated based on the finite-difference time- domain (FDTD) method for solvin...
The optimized use of the energy stored in induction motors during deceleration is still a competi... more The optimized use of the energy stored in induction motors during deceleration is still a competitive challenge especially for Electrical Vehicles (EV) drive systems designer and manufactures. There are many control algorithms depending on many different methodologies to reach a balance point to determine when exactly the regenerative braking will be used effectively and how long that whether it will be remained usage rather using the normal mechanical braking. The drive system allows the control/conversion of the mechanical energy stored in the EV’s inertial mass to convert the kinetic energy into electric energy. Further benefits of regenerative braking is fuel saving rather than the corresponding internal combustion engine ICE while ramp down/deceleration. This paper presents the simulated model and the concept of the control algorithm used in electrical vehicles. Moreover, it presents the main factors that affect the regenerated power and the optimization of using regenerative b...
Battery Management Systems (BMS) are used in many industrial and commercial systems to make the b... more Battery Management Systems (BMS) are used in many industrial and commercial systems to make the battery operation more efficient and for the estimation to keep the battery state, as long as possible, away from destructive state, to increase battery life time. For this purpose, many monitoring techniques are used to monitor the battery state of charge, temperature and current. In the current paper, the monitoring system for battery powered Electric Vehicles (EV) has been implemented and tested. This system evaluates and displays the battery temperature, charging/discharging current and State Of Charge (SOC) for the considered model battery. For monitoring purpose, digital and analog sensors with microcontrollers are used. The battery information and the obtained results explaining the main characteristics of the system are presented by photographs and some experimental results are given by the LCD screen.
The Journal of Engineering Research, 2016
The probable risk of electromagnetic fields produced inside high voltage substation is still cons... more The probable risk of electromagnetic fields produced inside high voltage substation is still considered as a competitive topic for utility designers and biomedical field researchers. Hence, the electromagnetic field levels and their induction inside human body should be pre-evaluated as early as the design stage of the substation. This paper deals with the computation of the electromagnetic fields inside a typical high voltage 500/220 kV air-insulated substation (AIS). The typical high voltage substation is simulated by developing multi-scripts of m-file Matlab software package to calculate both of electric and magnetic field individually. Moreover, analytical human body is simulated and allocated within the highly exposure zones of electromagnetic fields. The electromagnetic field induction inside the human body during live working conditions at different accessible positions is evaluated based on the power density vector (poynting vector) using the finite-difference time-domain (F...
Lecture Notes in Electrical Engineering, 2019
Traveling wave analysis process over the long High Voltages Direct Current (HVDC) transmission li... more Traveling wave analysis process over the long High Voltages Direct Current (HVDC) transmission lines for internal and external fault surges is rarely tackled and still as a competitive research issue. Transient surges resulting from different internal and external faults may cause sever risk failure to the long HVDC lines. Once, a fault occurs over the HVDC transmission line, high frequency traveling waves (TW) are generated. These traveling waves propagate away from the fault position in both direction of the transmission line with approximately the light speed. During internal faults the traveling waves can be detected at both line terminals. For external faults, the traveling wave can be detected only at one-line terminal with zero at the other terminal. Therefore, the identification method for internal and external fault surges for HVDC lines can be proposed by comparing the amplitude of the traveling waves at both ends of line. In the current paper, analysis has been investigat...
Power system perturbations are due to many reasons; one of the most common perturbation causes is... more Power system perturbations are due to many reasons; one of the most common perturbation causes is switching off/on the power capacitors. This paper monitors and discusses the overvoltages which appear on local and remote capacitor connected buses in power systems. Using the Fast Fourier Transfer (FFT), the total harmonic content of voltages and currents waveforms is also estimated at all buses. The power factor during different cases of switching modes “off/on” is monitored. The monitoring technique tackles not only the longitudinal long distance mutual effects of switching power capacitors between different buses but also evaluates the overvoltage durations. A relative long term monitoring is implemented using the Matlab/Simulink environment to show severity assessments in different switching modes on the transformers’ voltages and currents’ waveforms.
Transformers are major elements of any power systems. Normally they must be properly protected by... more Transformers are major elements of any power systems. Normally they must be properly protected by differential relays. This protection system should be precise and reliable via implementation of strong algorithms that able to differentiate between faulted and unfaulted condition to fully grantee of power continuity. This system should be able to detect the non-faulted condition, such as inrush currents which should not be activated in this condition meanwhile; it must be activated in internal fault conditions as fast as possible. This paper presents an approach for differential protection of power transformers this uses wavelet transform (WT) and adaptive network-based fuzzy inference system (ANFIS) to discriminate internal faults from inrush currents. The proposed algorithm has been designed based on the differences between both amplitudes of wavelet transform coefficients in a specific frequency band and rising and decaying duration generated by faults and inrush currents. The per...
This paper addresses the issue of the interaction of the human body with power frequency (50/60 H... more This paper addresses the issue of the interaction of the human body with power frequency (50/60 Hz) magnetic fields. Two human body models are used; a simple spheroid based on an analytical method and an approximate human shape based on finite element method (FEM). The employed human body models are positioned in two magnetic field sources; under a power transmission line and inside an electric power substation representing typical exposure cases. The magnetically induced currents inside human body due to the exposure to power frequency magnetic fields are evaluated. A number of parameters such as human dimensions and proximity to the current-carrying conductors are considered. A comparative analysis of the magnetic induction inside the human body due to the different human models and magnetic field sources is also presented.
High voltage substations are the main part in any power system utilities or municipalities. Prope... more High voltage substations are the main part in any power system utilities or municipalities. Proper design of lightning protection system should be done in the preliminary stage of the design process. In this paper, a typical high voltage substations of 500/220 kV is modeled by developing multi-scripts of Matlab m-files. To allocate and to simulate the whole carrying current conductors inside the substation and with 100 m length of input and output power lines. This is to calculate and to demonstrate the lightning electromagnetic fields inside the substations during lightning conditions using the Finite Difference Time Domain (FDTD) method with Maxwell’s equations. The effects of the posts allocations, its heights and surge arrestors to secure optimum protection zones are investigated. The electromagnetic fields distribution around the posts and inside the entire area of the substation during lightning conditions are evaluated. The electromagnetic fields for lightning over the input/...