Lightning stroke on a transmission tower structure is one of the major reasons that results in hi... more Lightning stroke on a transmission tower structure is one of the major reasons that results in high voltages at the tower arms due to the excessive lightning current flowing through the transmission tower to earth. The Surge voltage seen at the tower cross arm on the first tower close to a substation is the worst case. If this voltage is higher than the withstand level of the insulator string, the insulation of substation equipment will be exposed to transient over-voltage called fast front back-flashover (FFBF). The peak of this transient overvoltage is affected by the value of the system’s earthing resistance. This paper studies the effect of reducing the grounding resistance of both the surge arrestor (SA) and the first transmission line tower adjacent to a 66 kV substation on FFBF. Three case studies using PSCAD/EMTDC software are presented to simulate the variation of the potential sire at the substation equipment with different resistance values for the first tower and SA eart...
Proportional Integral Derivative (PID) controller is commonly used in process control systems. Tu... more Proportional Integral Derivative (PID) controller is commonly used in process control systems. Tuning PID controller parameters are a very challenging problem to improve performance and stability of a process. This paper presents a novel method for PID controller tuning problem using Linearized Biogeography-Based Optimization (LBBO) algorithm. Biogeography-Based Optimization (BBO) is an evolutionary optimization algorithm based on mathematical model of Biogeography; it permits of sharing the features among candidate solutions (habitats) represented by emigration and immigration. By using Matlab/Simulink and the squared error integral criterion as objective function. The algorithm is applied to benchmarks functions optimization design, and is then compared with Particle Swarm Optimization (PSO), BBO, and Modified Biogeography-Based Optimization (MBBO). Simulation results shown that the LBBO is an effective tuning method and has better performance compared with PSO, BBO, and MBBO.
This paper discusses the overvoltages resulting from various switching conditions
applied to the ... more This paper discusses the overvoltages resulting from various switching conditions applied to the existing 500 kV transmission lines of the Electricity Transmission Company of Egypt power system. The study is performed with computer simulations using Alternative Transients Program ATP. Details of the system modeling are outlined and appropriate representation for the various components is chosen. The effects of shunt reactors, surge arresters, capacitor banks, single line to ground faults, switching angel, load rejection and loading on the switching overvoltages are investigated. In addition, actual loads, actual characteristics for surge arresters and practical time for automatic reclosure are considered. The risk of insulation failure is computed during the previous conditions in the network using the statistical approach. The results show that the statistical overvoltage along the transmission line at Cairo reaches 4.39 p.u. and the risk of failure reaches 2.9x10-3 at no load. We conclude that the installation of the surge arresters on the main buses of the transmission line effectively solves the previous problem by reducing the overvoltages and risk of failures of insulation to acceptable values.
The increasing capacity of modern electricity supply systems as well as the higher voltages and c... more The increasing capacity of modern electricity supply systems as well as the higher voltages and currents have been matched by an over-spreading networks of earth return circuits (pipelines, cables,… etc.) close to the high voltage installations. Several workers have studied the effect of electric and magnetic fields separately, but in this paper it is intended to study the electric and magnetic effects of high voltage T.L. on metallic pipelines simultaneously. The combined effect depends on the conditions of power system (normal or fault conditions) and the operating power factor. A laboratory model is built to verify some of the theoretical results. A computer program is designed to calculate the induced voltage on metallic pipelines due to electric and magnetic field effects separately then the combined effect is calculated for different power factors. Also the effect of coating the pipeline, with a thin film of insulating material, is investigated.
The rapid increase in transmission voltages to fulfil higher demand of the
transmitted powers yie... more The rapid increase in transmission voltages to fulfil higher demand of the transmitted powers yields to put the switching surges as the governing factor in the insulation design process for EHV and UHV systems. The modern methods of insulation coordination make use of probabilistic concepts and statistical procedures especially for very high voltage systems. In this paper, a more sophisticated and accurate approach to the calculation of switching surge flash over rate (SSFOR) using Adaptive Neuro Fuzzy Interface System (ANFIS) is developed. The variation of switching overvoltage distribution along the transmission line under different system conditions is investigated. The statistical distributions of energization overvoltages for a typical Egyptian 500kV double line from High–dam to Samalut were derived from the results of 100 line energization cases with statistical (random) switching using alternate transient program (ATP). The statistical distributions and its key values, such as mean value, standard deviation and 2% statistical overvoltages values have been recorded. The effects of various parameters on the energization overvoltages distribution such as line length, source strength and the use of shunt reactors to control the switching surge overvoltage are considered. The developed ANFIS systems estimated the SSFOR for different input parameters for both the switching overvoltages and the insulation strength distributions with high accuracy.
In this paper it is intended to compute the electric field induced voltages on spherical and cyli... more In this paper it is intended to compute the electric field induced voltages on spherical and cylindrical tanks near the 500kV and 220kV Egyptian transmission lines using the charge simulation method. Models of charges are introduced to represent the induced surface charges on these tanks due to the electric field. The effect of conductors’ heights, tank radius, distance from the center line, phase sequence of the double circuit transmission line and height of the tank above ground on the induced voltages is investigated. A laboratory model is built to verify some of the results.
This paper illustrates switching overvoltages resulted from various switching conditions applied ... more This paper illustrates switching overvoltages resulted from various switching conditions applied to the existing 500 kV transmission lines of the Electricity Generating Authority of Egypt system. The study is performed with computer simulations using Alternative Transients Program (ATP). Details of the system modeling are outlined. The appropriate representation for the various components has been chosen. Also the effects of shunt reactors, surge arresters and loads on the switching overvoltages are investigated
this paper presents a scheme for classification of faults on double circuit parallel transmission... more this paper presents a scheme for classification of faults on double circuit parallel transmission lines using combination of discrete wavelet transform and support vector machine. Only one cycle post fault of the phase currents were employed to predict the fault type. Two features for each phase current were extracted using discrete wavelet transform. Thus, Total twelve features were extracted for the six phase currents. The training data were collected and support vector machine was employed to establish the fault classification unit. After that, the fault classification unit was tested for different fault states. The power system simulation was conducted using MATLAB/Simulink program. The proposed technique took into account the mutual coupling between the parallel transmission lines and the randomness of the faults on transmission line considering time of occurrence, fault location, fault type, fault resistance, and loading conditions. The results showed that the proposed technique can classify all the faults on the parallel transmission lines correctly.
Lightning stroke on a transmission tower structure is one of the major reasons that results in hi... more Lightning stroke on a transmission tower structure is one of the major reasons that results in high voltages at the tower arms due to the excessive lightning current flowing through the transmission tower to earth. The Surge voltage seen at the tower cross arm on the first tower close to a substation is the worst case. If this voltage is higher than the withstand level of the insulator string, the insulation of substation equipment will be exposed to transient over-voltage called fast front back-flashover (FFBF). The peak of this transient overvoltage is affected by the value of the system’s earthing resistance. This paper studies the effect of reducing the grounding resistance of both the surge arrestor (SA) and the first transmission line tower adjacent to a 66 kV substation on FFBF. Three case studies using PSCAD/EMTDC software are presented to simulate the variation of the potential sire at the substation equipment with different resistance values for the first tower and SA eart...
Proportional Integral Derivative (PID) controller is commonly used in process control systems. Tu... more Proportional Integral Derivative (PID) controller is commonly used in process control systems. Tuning PID controller parameters are a very challenging problem to improve performance and stability of a process. This paper presents a novel method for PID controller tuning problem using Linearized Biogeography-Based Optimization (LBBO) algorithm. Biogeography-Based Optimization (BBO) is an evolutionary optimization algorithm based on mathematical model of Biogeography; it permits of sharing the features among candidate solutions (habitats) represented by emigration and immigration. By using Matlab/Simulink and the squared error integral criterion as objective function. The algorithm is applied to benchmarks functions optimization design, and is then compared with Particle Swarm Optimization (PSO), BBO, and Modified Biogeography-Based Optimization (MBBO). Simulation results shown that the LBBO is an effective tuning method and has better performance compared with PSO, BBO, and MBBO.
This paper discusses the overvoltages resulting from various switching conditions
applied to the ... more This paper discusses the overvoltages resulting from various switching conditions applied to the existing 500 kV transmission lines of the Electricity Transmission Company of Egypt power system. The study is performed with computer simulations using Alternative Transients Program ATP. Details of the system modeling are outlined and appropriate representation for the various components is chosen. The effects of shunt reactors, surge arresters, capacitor banks, single line to ground faults, switching angel, load rejection and loading on the switching overvoltages are investigated. In addition, actual loads, actual characteristics for surge arresters and practical time for automatic reclosure are considered. The risk of insulation failure is computed during the previous conditions in the network using the statistical approach. The results show that the statistical overvoltage along the transmission line at Cairo reaches 4.39 p.u. and the risk of failure reaches 2.9x10-3 at no load. We conclude that the installation of the surge arresters on the main buses of the transmission line effectively solves the previous problem by reducing the overvoltages and risk of failures of insulation to acceptable values.
The increasing capacity of modern electricity supply systems as well as the higher voltages and c... more The increasing capacity of modern electricity supply systems as well as the higher voltages and currents have been matched by an over-spreading networks of earth return circuits (pipelines, cables,… etc.) close to the high voltage installations. Several workers have studied the effect of electric and magnetic fields separately, but in this paper it is intended to study the electric and magnetic effects of high voltage T.L. on metallic pipelines simultaneously. The combined effect depends on the conditions of power system (normal or fault conditions) and the operating power factor. A laboratory model is built to verify some of the theoretical results. A computer program is designed to calculate the induced voltage on metallic pipelines due to electric and magnetic field effects separately then the combined effect is calculated for different power factors. Also the effect of coating the pipeline, with a thin film of insulating material, is investigated.
The rapid increase in transmission voltages to fulfil higher demand of the
transmitted powers yie... more The rapid increase in transmission voltages to fulfil higher demand of the transmitted powers yields to put the switching surges as the governing factor in the insulation design process for EHV and UHV systems. The modern methods of insulation coordination make use of probabilistic concepts and statistical procedures especially for very high voltage systems. In this paper, a more sophisticated and accurate approach to the calculation of switching surge flash over rate (SSFOR) using Adaptive Neuro Fuzzy Interface System (ANFIS) is developed. The variation of switching overvoltage distribution along the transmission line under different system conditions is investigated. The statistical distributions of energization overvoltages for a typical Egyptian 500kV double line from High–dam to Samalut were derived from the results of 100 line energization cases with statistical (random) switching using alternate transient program (ATP). The statistical distributions and its key values, such as mean value, standard deviation and 2% statistical overvoltages values have been recorded. The effects of various parameters on the energization overvoltages distribution such as line length, source strength and the use of shunt reactors to control the switching surge overvoltage are considered. The developed ANFIS systems estimated the SSFOR for different input parameters for both the switching overvoltages and the insulation strength distributions with high accuracy.
In this paper it is intended to compute the electric field induced voltages on spherical and cyli... more In this paper it is intended to compute the electric field induced voltages on spherical and cylindrical tanks near the 500kV and 220kV Egyptian transmission lines using the charge simulation method. Models of charges are introduced to represent the induced surface charges on these tanks due to the electric field. The effect of conductors’ heights, tank radius, distance from the center line, phase sequence of the double circuit transmission line and height of the tank above ground on the induced voltages is investigated. A laboratory model is built to verify some of the results.
This paper illustrates switching overvoltages resulted from various switching conditions applied ... more This paper illustrates switching overvoltages resulted from various switching conditions applied to the existing 500 kV transmission lines of the Electricity Generating Authority of Egypt system. The study is performed with computer simulations using Alternative Transients Program (ATP). Details of the system modeling are outlined. The appropriate representation for the various components has been chosen. Also the effects of shunt reactors, surge arresters and loads on the switching overvoltages are investigated
this paper presents a scheme for classification of faults on double circuit parallel transmission... more this paper presents a scheme for classification of faults on double circuit parallel transmission lines using combination of discrete wavelet transform and support vector machine. Only one cycle post fault of the phase currents were employed to predict the fault type. Two features for each phase current were extracted using discrete wavelet transform. Thus, Total twelve features were extracted for the six phase currents. The training data were collected and support vector machine was employed to establish the fault classification unit. After that, the fault classification unit was tested for different fault states. The power system simulation was conducted using MATLAB/Simulink program. The proposed technique took into account the mutual coupling between the parallel transmission lines and the randomness of the faults on transmission line considering time of occurrence, fault location, fault type, fault resistance, and loading conditions. The results showed that the proposed technique can classify all the faults on the parallel transmission lines correctly.
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Papers by Ahmed M Emam
applied to the existing 500 kV transmission lines of the Electricity Transmission Company of Egypt
power system. The study is performed with computer simulations using Alternative Transients
Program ATP. Details of the system modeling are outlined and appropriate representation for the
various components is chosen. The effects of shunt reactors, surge arresters, capacitor banks,
single line to ground faults, switching angel, load rejection and loading on the switching
overvoltages are investigated. In addition, actual loads, actual characteristics for surge arresters
and practical time for automatic reclosure are considered. The risk of insulation failure is
computed during the previous conditions in the network using the statistical approach. The results
show that the statistical overvoltage along the transmission line at Cairo reaches 4.39 p.u. and the
risk of failure reaches 2.9x10-3 at no load. We conclude that the installation of the surge arresters
on the main buses of the transmission line effectively solves the previous problem by reducing the
overvoltages and risk of failures of insulation to acceptable values.
transmitted powers yields to put the switching surges as the governing factor in the
insulation design process for EHV and UHV systems. The modern methods of insulation
coordination make use of probabilistic concepts and statistical procedures especially for
very high voltage systems. In this paper, a more sophisticated and accurate approach to
the calculation of switching surge flash over rate (SSFOR) using Adaptive Neuro Fuzzy
Interface System (ANFIS) is developed. The variation of switching overvoltage distribution
along the transmission line under different system conditions is investigated. The
statistical distributions of energization overvoltages for a typical Egyptian 500kV double
line from High–dam to Samalut were derived from the results of 100 line energization
cases with statistical (random) switching using alternate transient program (ATP). The
statistical distributions and its key values, such as mean value, standard deviation and
2% statistical overvoltages values have been recorded. The effects of various parameters
on the energization overvoltages distribution such as line length, source strength and the
use of shunt reactors to control the switching surge overvoltage are considered. The
developed ANFIS systems estimated the SSFOR for different input parameters for both
the switching overvoltages and the insulation strength distributions with high accuracy.
of discrete wavelet transform and support vector machine. Only one cycle post fault of the phase currents were employed to
predict the fault type. Two features for each phase current were extracted using discrete wavelet transform. Thus, Total twelve
features were extracted for the six phase currents. The training data were collected and support vector machine was employed to
establish the fault classification unit. After that, the fault classification unit was tested for different fault states. The power system
simulation was conducted using MATLAB/Simulink program. The proposed technique took into account the mutual coupling
between the parallel transmission lines and the randomness of the faults on transmission line considering time of occurrence, fault
location, fault type, fault resistance, and loading conditions. The results showed that the proposed technique can classify all the
faults on the parallel transmission lines correctly.
applied to the existing 500 kV transmission lines of the Electricity Transmission Company of Egypt
power system. The study is performed with computer simulations using Alternative Transients
Program ATP. Details of the system modeling are outlined and appropriate representation for the
various components is chosen. The effects of shunt reactors, surge arresters, capacitor banks,
single line to ground faults, switching angel, load rejection and loading on the switching
overvoltages are investigated. In addition, actual loads, actual characteristics for surge arresters
and practical time for automatic reclosure are considered. The risk of insulation failure is
computed during the previous conditions in the network using the statistical approach. The results
show that the statistical overvoltage along the transmission line at Cairo reaches 4.39 p.u. and the
risk of failure reaches 2.9x10-3 at no load. We conclude that the installation of the surge arresters
on the main buses of the transmission line effectively solves the previous problem by reducing the
overvoltages and risk of failures of insulation to acceptable values.
transmitted powers yields to put the switching surges as the governing factor in the
insulation design process for EHV and UHV systems. The modern methods of insulation
coordination make use of probabilistic concepts and statistical procedures especially for
very high voltage systems. In this paper, a more sophisticated and accurate approach to
the calculation of switching surge flash over rate (SSFOR) using Adaptive Neuro Fuzzy
Interface System (ANFIS) is developed. The variation of switching overvoltage distribution
along the transmission line under different system conditions is investigated. The
statistical distributions of energization overvoltages for a typical Egyptian 500kV double
line from High–dam to Samalut were derived from the results of 100 line energization
cases with statistical (random) switching using alternate transient program (ATP). The
statistical distributions and its key values, such as mean value, standard deviation and
2% statistical overvoltages values have been recorded. The effects of various parameters
on the energization overvoltages distribution such as line length, source strength and the
use of shunt reactors to control the switching surge overvoltage are considered. The
developed ANFIS systems estimated the SSFOR for different input parameters for both
the switching overvoltages and the insulation strength distributions with high accuracy.
of discrete wavelet transform and support vector machine. Only one cycle post fault of the phase currents were employed to
predict the fault type. Two features for each phase current were extracted using discrete wavelet transform. Thus, Total twelve
features were extracted for the six phase currents. The training data were collected and support vector machine was employed to
establish the fault classification unit. After that, the fault classification unit was tested for different fault states. The power system
simulation was conducted using MATLAB/Simulink program. The proposed technique took into account the mutual coupling
between the parallel transmission lines and the randomness of the faults on transmission line considering time of occurrence, fault
location, fault type, fault resistance, and loading conditions. The results showed that the proposed technique can classify all the
faults on the parallel transmission lines correctly.