ahmed refaat | Port Said University (original) (raw)

Papers by ahmed refaat

Research paper thumbnail of A Comparative Study of Three Winding Configurations for Six-Phase Induction Motors

Earth and Environmental Sciences Library, Dec 31, 2023

Research paper thumbnail of Performance evaluation of a novel self-tuning particle swarm optimization algorithm-based maximum power point tracker for porton exchange membrane fuel cells under different operating conditions

Energy Conversion and Management, Jan 31, 2024

The power generated by a proton exchange membrane fuel cell (PEMFC) is heavily impacted by the ch... more The power generated by a proton exchange membrane fuel cell (PEMFC) is heavily impacted by the change in membrane water content (MWC) and cell temperature. Since PEMFC stacks exhibit nonlinear characteristics, it is crucial to employ a controller that can accurately track the maximum power point (MPP) and extract the most efficient power from the fuel cell (FC) stack. This article introduces a novel MPP tracking technique, based on a self-tuning particle swarm optimization (ST-PSO) algorithm, to maximize power output from PEMFC under different operational conditions. The performance of the ST-PSO algorithm is evaluated through numerical simulations and compared to four well-known metaheuristic algorithms. The results indicate that the proposed ST-PSO-based MPPT technique surpasses the other metaheuristic methods in terms of extracting the maximum power, achieving fast-tracking, and minimizing power fluctuations in various operating conditions. It attained an MPPT efficiency, consistently exceeding 99.602 % and 99.545 %, while also achieving rapid tracking times of no more than 0.366 s and 0.297 s for the two tested scenarios. Moreover, the ST-PSO controller exhibits robustness and consistent tracking of the MPP. Experimental validation of the ST-PSO controller confirms its robustness and superiority over the other tested algorithm, achieving the highest MPPT efficiency of approximately 98.94 % with a rapid tracking time of 2.0 s. Additionally, it demonstrates the lowest power fluctuations of about 2.26 %, providing a stable power output.

Research paper thumbnail of A Comparative Study of Two Metaheuristic MPPT Techniques to Extract Maximum Power from PV Array under Different Partial Shading Patterns

Research paper thumbnail of Two Bio-inspired MPPT Algorithms to Harvest the Maximum Power from Partially Shaded PV Arrays

2022 Conference of Russian Young Researchers in Electrical and Electronic Engineering (ElConRus)

Owing to the complex nonlinear characteristics of photovoltaic (PV) panels, the P-V curve exhibit... more Owing to the complex nonlinear characteristics of photovoltaic (PV) panels, the P-V curve exhibits numerous peaks during partial shading (PS) that include several local peaks (LPs) along with the global peak (GP). Classical maximum power point tracking (MPPT) algorithms are not appropriate to successfully follow the GP under PS conditions. To optimize the energy captured from the PV array, advanced MPPT algorithms are necessary to track the GP. This paper presents two recognized bio-inspired based MPPT algorithms known as Cuckoo Search (CS) and Flower Pollination (FP) techniques. A comparative investigation is set up in order to demonstrate the performance of partially shaded PV arrays for the presented algorithms. According to the simulation results, both algorithms can follow the GP of the partially shaded PV arrays with fast convergence time and accuracy. Although the FP algorithm can track the GP, the CS algorithm superior it with less convergence time and more accuracy.

Research paper thumbnail of A Novel Grid-Connected Photovoltaic Centralized Inverter Topology to Improve the Power Harvest during Partial Shading Condition

Research paper thumbnail of Энергоменеджмент гибридной энергетической микросети на сутки вперед

Известия Академии наук СССР, 2021

Research paper thumbnail of Optimal Allocation of FACTS Devices based on Multi-Objective Multi-Verse Optimizer Algorithm for Multi-Objective Power System Optimization Problems

2020 International Multi-Conference on Industrial Engineering and Modern Technologies (FarEastCon), Oct 6, 2020

A new multi-objective optimization algorithm based on a stochastic population technique known as ... more A new multi-objective optimization algorithm based on a stochastic population technique known as the Multi-Objective Multi-Verse Optimizer (MOMVO) is proposed for the allocation of Flexible AC Transmission System (FACTS) devices in the power system network. The MOMVO determines the optimal setting and location of the FACTS controllers to minimize the active power losses, voltage deviation of the system, and the installation cost of the FACTS devices simultaneously. In this work, the Static VAR Compensator (SVC) and Thyristor-Controlled Series Compensator (TCSC) devices are used as FACTS controllers. Simulations have been performed on MATLAB with an additional MATPOWER package to evaluate the performance of the MOMVO algorithm on the standard IEEE 57 bus system. The results show that the MOMVO algorithm is efficient in determining the optimal settings and locations of the FACTS controllers that improve system performance.

Research paper thumbnail of Maximum Power Point Tracking for Grid-tied PV System Using Adaptive Neuro-Fuzzy Inference System

2021 International Conference on Electrotechnical Complexes and Systems (ICOECS)

This article provides a control approach of a photovoltaic (PV) system connected to the grid (PVS... more This article provides a control approach of a photovoltaic (PV) system connected to the grid (PVSCG). The system consists of a 500 KW PV array, boost converter, and two-level three-phase voltage source inverter (VSI). The DC-DC boost converter in the PV system is controlled via an Adaptive Neuro-fuzzy inference system maximum power point tracking (ANFIS-MPPT) algorithm to optimize the generated power of the PV system. In this technique, the PI control loop is eliminated, and the duty cycle is directly adapted by the MPPT method. Consequently, the MPPT control loop is simplified, as the tuning method for calculating and estimating the gain of the PI controller is eliminated. Also, a comprehensive decoupled current control technique in rotating d-q synchronous reference frame (SRF) is executed to transfer the maximum power extracted to the grid. Simulation results of the system on MATLAB/Simulink software are performed under different levels of solar radiation and cell temperature. The effectiveness of the suggested controller to transfer the generated power to the grid is investigated.

Research paper thumbnail of A novel metaheuristic MPPT technique based on enhanced autonomous group Particle Swarm Optimization Algorithm to track the GMPP under partial shading conditions - Experimental validation

Energy Conversion and Management

Research paper thumbnail of Determination of mutual inductances and electrodynamic forces between the coil and the coaxial solenoid in a symmetrical arrangement

Transactions of the Krylov State Research Centre, 2021

Object and purpose of research. Mutual inductances are among the main parameters of electrical ci... more Object and purpose of research. Mutual inductances are among the main parameters of electrical circuits, and their determination is the most important task for studying the physical processes occurring in them, including the occurrence of electrodynamic forces. Coaxial coils and solenoids are very common part of electrical devices, and finding mutual inductances and electrodynamic forces in them has a great practical importance. Materials and methods. Methods of theoretical electrical engineering are used. Main results. Expressions for mutual inductance are obtained, and they are based on the decomposition of the solenoid into its external and internal parts relative to the end planes of the coil. Conclusion. On the basis of the undertaken analysis, alternative expressions for mutual inductances are obtained.

Research paper thumbnail of A Control Methodology of Three Phase Grid Connected PV System

This paper proposes a control methodology of three phase grid connected PV system and its control... more This paper proposes a control methodology of three phase grid connected PV system and its control schemes for applications in distributed generation (DG) systems. The system utilizes a two stage energy conversion power conditioning unit (PCU) topology composed of a DC-DC boost converter and two level-three phase voltage source inverter (VSI). The DC-DC converter is used to extract maximum power from the PV array and boost its output voltage. An incremental conductance maximum power point tracking (MPPT) technique is proposed with direct control method in which duty cycle is adjusted to achieve the maximum power point (MPP). The VSI is used for converting the maximum power extracted by DC-DC converter to AC power using a full decoupled current control strategy in rotating d-q synchronous reference frame. Simulation results on MATLAB/Simulink software are carried out to confirm the system operation. Finally, a case study is conducted to demonstrate the effect of MPPT efficiency, inter...

Research paper thumbnail of A Modified Restraint Method to Enhance the Performance of Differential Protection for Overhead Transmission Lines

2019 IEEE Conference of Russian Young Researchers in Electrical and Electronic Engineering (EIConRus)

Recently the advancement of microprocessor-based line current differential schemes renewed the in... more Recently the advancement of microprocessor-based line current differential schemes renewed the interest of line differential protection. However, under unbalanced condition differential schemes suffer from mal-operation because of unbalanced currents. Restraint methods are the most commonly used to mitigate the effect of these currents. The main challenge of these methods is that, restraining signal (due to an external fault) decreases significantly with increasing magnetization current of current transformers, while the differential signal increases. This leads to a reduction of the sensitivity of protection or increase tripping time to prevent mal-operation. This paper proposes a modified restraint method based on a capacitive compensation current signal to improve the sensitivity of transmission lines differential protection. Computer simulation is carried out using MATLAB/Simulink in order to confirm the performance of the proposed method and develop recommendations for increasing the sensitivity of protection.

Research paper thumbnail of Maximum Power Extraction from Polymer Electrolyte Membrane (PEM) Fuel Cell Based on Deterministic Particle Swarm Optimization Algorithm

2022 Conference of Russian Young Researchers in Electrical and Electronic Engineering (ElConRus)

In the power-current curve of Polymer Electrolyte Membrane Fuel Cell (PEMFC), the maximum power p... more In the power-current curve of Polymer Electrolyte Membrane Fuel Cell (PEMFC), the maximum power point (MPP) locus is substantially impacted by the cell temperature and membrane water content. Consequently, the MPP Tracker is significant for enhancing fuel cell (FC) energy efficiency. In this work, for the first time, the Deterministic Particle Swarm Optimization (DPSO) technique is implemented to follow the MPP under various FC temperatures and water contents. The PEMFC model based on the DPSO technique is set up on Matlab/Simulink and compared to standard PSO (SPSO) to confirm the FC stack operation under different operating parameters. Simulation results show that both techniques can track the MPP of the FC stack under different conditions. Although the SPSO method can trace the MPP, the DPSO program outstanding it with higher convergence speed and lower power oscillation around the MPP.

Research paper thumbnail of A Control Methodology of Grid-Connected PV System to Verify The Standard IEEE 929-2000

This paper presents a control methodology of a 500 KW three phase grid connected PV system and it... more This paper presents a control methodology of a 500 KW three phase grid connected PV system and its control schemes when it is used as a distributed generation (DG) system. The system utilizes a two stage energy conversion power conditioning unit (PCU) topology composed of a DC-DC boost converter and two level-three phase voltage source inverter (VSI). The DC-DC converter is used to boost the output voltage of the PV array and extract maximum power under different environmental conditions. An incremental conductance maximum power point tracking (MPPT) technique is proposed with direct control method in which duty cycle is adjusted to achieve the maximum power point (MPP). The VSI is used for converting the maximum input power from DC-DC converter to AC power by using a full decoupled current control strategy in rotating d-q reference frame. Finally, simulation results on MATLAB/Simulink software are carried out to validate the performance of the proposed system.

Research paper thumbnail of An Optimal Day-Ahead Operation Strategy for Hybrid Energy Microgrid

2019 IEEE Conference of Russian Young Researchers in Electrical and Electronic Engineering (EIConRus), 2019

This paper proposes a strategy for optimal day-ahead operation of a microgrid. The latter include... more This paper proposes a strategy for optimal day-ahead operation of a microgrid. The latter includes hybrid energy resources and an energy storage system (ESS). The forecasted day-ahead hourly average of metrological data and loads are fed into the energy management system (EMS). Accordingly, it decides the day-ahead hourly active and reactive power shares of each energy source. It also identifies the ESS charging/discharging periods and the tap setting of the main grid coupling transformer. The overall objective is to maximize the microgrid profit satisfying all constraints. The microgrid purchases/sells active and reactive powers from/to the main grid with time-varying energy price. The day-ahead operation of the microgrid is formulated as an optimization problem solved by a combined rule base - heuristic approach. The modified particle swarm optimization (PSO) technique is used as optimization solver. Moreover, the efficacy of the proposed EMS is verified by performance comparison to recent literature.

Research paper thumbnail of A Novel Photovoltaic Current Collector Optimizer to Extract Maximum Power during Partial Shading or Mismatch Conditions

2019 IEEE Conference of Russian Young Researchers in Electrical and Electronic Engineering (EIConRus)

Partial shading and mismatch between photovoltaic (PV) panels have significant negative effects o... more Partial shading and mismatch between photovoltaic (PV) panels have significant negative effects on the power generated from PV array and total efficiency of the PV system. Both conditions cause a non-uniform aging of PV modules and may lead to hot spot phenomenon that destroys the PV panels. Under both conditions, the characteristics of the entire PV array are deformed and exhibit multiple peaks, including global and local maximum power points (MPPs) that need an intelligent MPP tracking algorithm to track the global MPP. This paper proposes a new photovoltaic current collector optimizer (CCO) to improve the power captured from PV array in case of partial shading or mismatch conditions. The PV modules are stacked by CCOs and then interfaced to the utility grid through an inverter, which introduces a new topology of centralized inverter technology. Simulation results show a remarkable increase in output generated power for the proposed centralized topology compared to conventional ones.

Research paper thumbnail of A New Photovoltaic Current Collector Optimizer to Enhance the Performance of Centralized Inverter Topologies

Advances in Intelligent Systems and Computing, 2019

Centralized inverter topologies are the current preferred technology for medium and large-scale g... more Centralized inverter topologies are the current preferred technology for medium and large-scale grid-connected photovoltaic (PV) installation because of their low cost and simplicity. However, the output power of these traditional topologies is mainly suffered from partial shading effects and mismatch between PV modules. Power losses due to shadow may reach up to 30% of total power expected, depending on PV array configuration and atmospheric conditions. This paper proposes a novel grid-connected centralized inverter topology based on a new photovoltaic current collector optimizer (CCO) to enhance the power extracted from PV array during partial shading or mismatch conditions. Computer simulation is carried out using MATLAB/Simulink in order to confirm the performance of the proposed topology. Simulation results show that the proposed topology offers an excellent steady-state response, fast dynamic response, perfect and robust tracking of the maximum power point during partial shading condition.

Research paper thumbnail of Optimal placement and sizing of FACTS devices based on Autonomous Groups Particle Swarm Optimization technique

Archives of Electrical Engineering, 2021

This paper presents the application of Flexible Alternating Current Transmission System (FACTS) d... more This paper presents the application of Flexible Alternating Current Transmission System (FACTS) devices based on heuristic algorithms in power systems. The work proposes the Autonomous Groups Particle Swarm Optimization (AGPSO) approach for the optimal placement and sizing of the Static Var Compensator (SVC) to minimize the total active power losses in transmission lines. A comparative study is conducted with other heuristic optimization algorithms such as Particle Swarm Optimization (PSO), Timevarying Acceleration Coefficients PSO (TACPSO), Improved PSO (IPSO), Modified PSO (MPSO), and Moth-Flam Optimization (MFO) algorithms to confirm the efficacy of the proposed algorithm. Computer simulations have been carried out on MATLAB with the MATPOWER additional package to evaluate the performance of the AGPSO algorithm on the IEEE 14 and 30 bus systems. The simulation results show that the proposed algorithm offers the best performance among all algorithms with the lowest active power losses and the highest convergence rate.

Research paper thumbnail of Optimal operation of a hybrid-energy microgrid with energy storage system

E3S Web of Conferences, 2019

In this paper, a day-ahead profit-maximizing energy management scheme for a grid-tied microgrid o... more In this paper, a day-ahead profit-maximizing energy management scheme for a grid-tied microgrid operation is proposed. The microgrid contains various types of distributed energy resources (DERs) and an inverter-interfaced battery-bank storage system. The average of day-ahead hourly forecasted data for loads, wind speed, and solar radiation are inputted into the framework of energy management (EMF). To optimize the microgrid performance, EMF determines the hourly dispatch of reactive and active power for each DER. Also, it specifies the discharging and charging times of the energy storage system and the onload tap changer position setting of the transformer connected to the main grid. The main aim is to maximize the revenue of microgrid meeting all technical limitations. The main grid can sell/buy reactive and active powers to/from the microgrid with a variable daily energy price of the market. A collective rule base-BAT algorithm is implemented as a solver of the energy management o...

Research paper thumbnail of Optimum Power Extraction from Non-Uniform Aged PV Array Using Current Collector Optimizer Topology

Elektrichestvo, 2019

Harsh outdoor operating circumstances of photovoltaic (PV) array leads to non-uniform aging pheno... more Harsh outdoor operating circumstances of photovoltaic (PV) array leads to non-uniform aging phenomenon among PV panels which in turn reduces the life span of the PV modules and the energy efficiency of the whole array. Under non-uniform aging conditions for series-parallel (SP) connected PV modules, the characteristics of the entire PV array are deformed resulting in multiple peaks where one of them is the global peak. The appearance of such multiple peaks can mislead traditional maximum power point tracking (MPPT) techniques to get trapped at local peaks, which leads to misleading power losses. This paper proposes a current collector optimizer (CCO) topology to extract maximum power from a non-uniform aged PV array. By using CCO topology, the PV array characteristics have a unique maximum power point (MPP) which easy to follow by a simple MPPT algorithm. Consequently, the proposed topology does not suffer from misleading power losses. Besides, the CCO topology requires offline rearrangement of aged modules to obtain the optimal maximum power. A comparative study is conducted to demonstrate the efficacy of the proposed topology. Ultimately, the paper presents an offline algorithm for rearranging erratic aged CCO modules to extract the optimum power from large-scale PV arrays.

Research paper thumbnail of A Comparative Study of Three Winding Configurations for Six-Phase Induction Motors

Earth and Environmental Sciences Library, Dec 31, 2023

Research paper thumbnail of Performance evaluation of a novel self-tuning particle swarm optimization algorithm-based maximum power point tracker for porton exchange membrane fuel cells under different operating conditions

Energy Conversion and Management, Jan 31, 2024

The power generated by a proton exchange membrane fuel cell (PEMFC) is heavily impacted by the ch... more The power generated by a proton exchange membrane fuel cell (PEMFC) is heavily impacted by the change in membrane water content (MWC) and cell temperature. Since PEMFC stacks exhibit nonlinear characteristics, it is crucial to employ a controller that can accurately track the maximum power point (MPP) and extract the most efficient power from the fuel cell (FC) stack. This article introduces a novel MPP tracking technique, based on a self-tuning particle swarm optimization (ST-PSO) algorithm, to maximize power output from PEMFC under different operational conditions. The performance of the ST-PSO algorithm is evaluated through numerical simulations and compared to four well-known metaheuristic algorithms. The results indicate that the proposed ST-PSO-based MPPT technique surpasses the other metaheuristic methods in terms of extracting the maximum power, achieving fast-tracking, and minimizing power fluctuations in various operating conditions. It attained an MPPT efficiency, consistently exceeding 99.602 % and 99.545 %, while also achieving rapid tracking times of no more than 0.366 s and 0.297 s for the two tested scenarios. Moreover, the ST-PSO controller exhibits robustness and consistent tracking of the MPP. Experimental validation of the ST-PSO controller confirms its robustness and superiority over the other tested algorithm, achieving the highest MPPT efficiency of approximately 98.94 % with a rapid tracking time of 2.0 s. Additionally, it demonstrates the lowest power fluctuations of about 2.26 %, providing a stable power output.

Research paper thumbnail of A Comparative Study of Two Metaheuristic MPPT Techniques to Extract Maximum Power from PV Array under Different Partial Shading Patterns

Research paper thumbnail of Two Bio-inspired MPPT Algorithms to Harvest the Maximum Power from Partially Shaded PV Arrays

2022 Conference of Russian Young Researchers in Electrical and Electronic Engineering (ElConRus)

Owing to the complex nonlinear characteristics of photovoltaic (PV) panels, the P-V curve exhibit... more Owing to the complex nonlinear characteristics of photovoltaic (PV) panels, the P-V curve exhibits numerous peaks during partial shading (PS) that include several local peaks (LPs) along with the global peak (GP). Classical maximum power point tracking (MPPT) algorithms are not appropriate to successfully follow the GP under PS conditions. To optimize the energy captured from the PV array, advanced MPPT algorithms are necessary to track the GP. This paper presents two recognized bio-inspired based MPPT algorithms known as Cuckoo Search (CS) and Flower Pollination (FP) techniques. A comparative investigation is set up in order to demonstrate the performance of partially shaded PV arrays for the presented algorithms. According to the simulation results, both algorithms can follow the GP of the partially shaded PV arrays with fast convergence time and accuracy. Although the FP algorithm can track the GP, the CS algorithm superior it with less convergence time and more accuracy.

Research paper thumbnail of A Novel Grid-Connected Photovoltaic Centralized Inverter Topology to Improve the Power Harvest during Partial Shading Condition

Research paper thumbnail of Энергоменеджмент гибридной энергетической микросети на сутки вперед

Известия Академии наук СССР, 2021

Research paper thumbnail of Optimal Allocation of FACTS Devices based on Multi-Objective Multi-Verse Optimizer Algorithm for Multi-Objective Power System Optimization Problems

2020 International Multi-Conference on Industrial Engineering and Modern Technologies (FarEastCon), Oct 6, 2020

A new multi-objective optimization algorithm based on a stochastic population technique known as ... more A new multi-objective optimization algorithm based on a stochastic population technique known as the Multi-Objective Multi-Verse Optimizer (MOMVO) is proposed for the allocation of Flexible AC Transmission System (FACTS) devices in the power system network. The MOMVO determines the optimal setting and location of the FACTS controllers to minimize the active power losses, voltage deviation of the system, and the installation cost of the FACTS devices simultaneously. In this work, the Static VAR Compensator (SVC) and Thyristor-Controlled Series Compensator (TCSC) devices are used as FACTS controllers. Simulations have been performed on MATLAB with an additional MATPOWER package to evaluate the performance of the MOMVO algorithm on the standard IEEE 57 bus system. The results show that the MOMVO algorithm is efficient in determining the optimal settings and locations of the FACTS controllers that improve system performance.

Research paper thumbnail of Maximum Power Point Tracking for Grid-tied PV System Using Adaptive Neuro-Fuzzy Inference System

2021 International Conference on Electrotechnical Complexes and Systems (ICOECS)

This article provides a control approach of a photovoltaic (PV) system connected to the grid (PVS... more This article provides a control approach of a photovoltaic (PV) system connected to the grid (PVSCG). The system consists of a 500 KW PV array, boost converter, and two-level three-phase voltage source inverter (VSI). The DC-DC boost converter in the PV system is controlled via an Adaptive Neuro-fuzzy inference system maximum power point tracking (ANFIS-MPPT) algorithm to optimize the generated power of the PV system. In this technique, the PI control loop is eliminated, and the duty cycle is directly adapted by the MPPT method. Consequently, the MPPT control loop is simplified, as the tuning method for calculating and estimating the gain of the PI controller is eliminated. Also, a comprehensive decoupled current control technique in rotating d-q synchronous reference frame (SRF) is executed to transfer the maximum power extracted to the grid. Simulation results of the system on MATLAB/Simulink software are performed under different levels of solar radiation and cell temperature. The effectiveness of the suggested controller to transfer the generated power to the grid is investigated.

Research paper thumbnail of A novel metaheuristic MPPT technique based on enhanced autonomous group Particle Swarm Optimization Algorithm to track the GMPP under partial shading conditions - Experimental validation

Energy Conversion and Management

Research paper thumbnail of Determination of mutual inductances and electrodynamic forces between the coil and the coaxial solenoid in a symmetrical arrangement

Transactions of the Krylov State Research Centre, 2021

Object and purpose of research. Mutual inductances are among the main parameters of electrical ci... more Object and purpose of research. Mutual inductances are among the main parameters of electrical circuits, and their determination is the most important task for studying the physical processes occurring in them, including the occurrence of electrodynamic forces. Coaxial coils and solenoids are very common part of electrical devices, and finding mutual inductances and electrodynamic forces in them has a great practical importance. Materials and methods. Methods of theoretical electrical engineering are used. Main results. Expressions for mutual inductance are obtained, and they are based on the decomposition of the solenoid into its external and internal parts relative to the end planes of the coil. Conclusion. On the basis of the undertaken analysis, alternative expressions for mutual inductances are obtained.

Research paper thumbnail of A Control Methodology of Three Phase Grid Connected PV System

This paper proposes a control methodology of three phase grid connected PV system and its control... more This paper proposes a control methodology of three phase grid connected PV system and its control schemes for applications in distributed generation (DG) systems. The system utilizes a two stage energy conversion power conditioning unit (PCU) topology composed of a DC-DC boost converter and two level-three phase voltage source inverter (VSI). The DC-DC converter is used to extract maximum power from the PV array and boost its output voltage. An incremental conductance maximum power point tracking (MPPT) technique is proposed with direct control method in which duty cycle is adjusted to achieve the maximum power point (MPP). The VSI is used for converting the maximum power extracted by DC-DC converter to AC power using a full decoupled current control strategy in rotating d-q synchronous reference frame. Simulation results on MATLAB/Simulink software are carried out to confirm the system operation. Finally, a case study is conducted to demonstrate the effect of MPPT efficiency, inter...

Research paper thumbnail of A Modified Restraint Method to Enhance the Performance of Differential Protection for Overhead Transmission Lines

2019 IEEE Conference of Russian Young Researchers in Electrical and Electronic Engineering (EIConRus)

Recently the advancement of microprocessor-based line current differential schemes renewed the in... more Recently the advancement of microprocessor-based line current differential schemes renewed the interest of line differential protection. However, under unbalanced condition differential schemes suffer from mal-operation because of unbalanced currents. Restraint methods are the most commonly used to mitigate the effect of these currents. The main challenge of these methods is that, restraining signal (due to an external fault) decreases significantly with increasing magnetization current of current transformers, while the differential signal increases. This leads to a reduction of the sensitivity of protection or increase tripping time to prevent mal-operation. This paper proposes a modified restraint method based on a capacitive compensation current signal to improve the sensitivity of transmission lines differential protection. Computer simulation is carried out using MATLAB/Simulink in order to confirm the performance of the proposed method and develop recommendations for increasing the sensitivity of protection.

Research paper thumbnail of Maximum Power Extraction from Polymer Electrolyte Membrane (PEM) Fuel Cell Based on Deterministic Particle Swarm Optimization Algorithm

2022 Conference of Russian Young Researchers in Electrical and Electronic Engineering (ElConRus)

In the power-current curve of Polymer Electrolyte Membrane Fuel Cell (PEMFC), the maximum power p... more In the power-current curve of Polymer Electrolyte Membrane Fuel Cell (PEMFC), the maximum power point (MPP) locus is substantially impacted by the cell temperature and membrane water content. Consequently, the MPP Tracker is significant for enhancing fuel cell (FC) energy efficiency. In this work, for the first time, the Deterministic Particle Swarm Optimization (DPSO) technique is implemented to follow the MPP under various FC temperatures and water contents. The PEMFC model based on the DPSO technique is set up on Matlab/Simulink and compared to standard PSO (SPSO) to confirm the FC stack operation under different operating parameters. Simulation results show that both techniques can track the MPP of the FC stack under different conditions. Although the SPSO method can trace the MPP, the DPSO program outstanding it with higher convergence speed and lower power oscillation around the MPP.

Research paper thumbnail of A Control Methodology of Grid-Connected PV System to Verify The Standard IEEE 929-2000

This paper presents a control methodology of a 500 KW three phase grid connected PV system and it... more This paper presents a control methodology of a 500 KW three phase grid connected PV system and its control schemes when it is used as a distributed generation (DG) system. The system utilizes a two stage energy conversion power conditioning unit (PCU) topology composed of a DC-DC boost converter and two level-three phase voltage source inverter (VSI). The DC-DC converter is used to boost the output voltage of the PV array and extract maximum power under different environmental conditions. An incremental conductance maximum power point tracking (MPPT) technique is proposed with direct control method in which duty cycle is adjusted to achieve the maximum power point (MPP). The VSI is used for converting the maximum input power from DC-DC converter to AC power by using a full decoupled current control strategy in rotating d-q reference frame. Finally, simulation results on MATLAB/Simulink software are carried out to validate the performance of the proposed system.

Research paper thumbnail of An Optimal Day-Ahead Operation Strategy for Hybrid Energy Microgrid

2019 IEEE Conference of Russian Young Researchers in Electrical and Electronic Engineering (EIConRus), 2019

This paper proposes a strategy for optimal day-ahead operation of a microgrid. The latter include... more This paper proposes a strategy for optimal day-ahead operation of a microgrid. The latter includes hybrid energy resources and an energy storage system (ESS). The forecasted day-ahead hourly average of metrological data and loads are fed into the energy management system (EMS). Accordingly, it decides the day-ahead hourly active and reactive power shares of each energy source. It also identifies the ESS charging/discharging periods and the tap setting of the main grid coupling transformer. The overall objective is to maximize the microgrid profit satisfying all constraints. The microgrid purchases/sells active and reactive powers from/to the main grid with time-varying energy price. The day-ahead operation of the microgrid is formulated as an optimization problem solved by a combined rule base - heuristic approach. The modified particle swarm optimization (PSO) technique is used as optimization solver. Moreover, the efficacy of the proposed EMS is verified by performance comparison to recent literature.

Research paper thumbnail of A Novel Photovoltaic Current Collector Optimizer to Extract Maximum Power during Partial Shading or Mismatch Conditions

2019 IEEE Conference of Russian Young Researchers in Electrical and Electronic Engineering (EIConRus)

Partial shading and mismatch between photovoltaic (PV) panels have significant negative effects o... more Partial shading and mismatch between photovoltaic (PV) panels have significant negative effects on the power generated from PV array and total efficiency of the PV system. Both conditions cause a non-uniform aging of PV modules and may lead to hot spot phenomenon that destroys the PV panels. Under both conditions, the characteristics of the entire PV array are deformed and exhibit multiple peaks, including global and local maximum power points (MPPs) that need an intelligent MPP tracking algorithm to track the global MPP. This paper proposes a new photovoltaic current collector optimizer (CCO) to improve the power captured from PV array in case of partial shading or mismatch conditions. The PV modules are stacked by CCOs and then interfaced to the utility grid through an inverter, which introduces a new topology of centralized inverter technology. Simulation results show a remarkable increase in output generated power for the proposed centralized topology compared to conventional ones.

Research paper thumbnail of A New Photovoltaic Current Collector Optimizer to Enhance the Performance of Centralized Inverter Topologies

Advances in Intelligent Systems and Computing, 2019

Centralized inverter topologies are the current preferred technology for medium and large-scale g... more Centralized inverter topologies are the current preferred technology for medium and large-scale grid-connected photovoltaic (PV) installation because of their low cost and simplicity. However, the output power of these traditional topologies is mainly suffered from partial shading effects and mismatch between PV modules. Power losses due to shadow may reach up to 30% of total power expected, depending on PV array configuration and atmospheric conditions. This paper proposes a novel grid-connected centralized inverter topology based on a new photovoltaic current collector optimizer (CCO) to enhance the power extracted from PV array during partial shading or mismatch conditions. Computer simulation is carried out using MATLAB/Simulink in order to confirm the performance of the proposed topology. Simulation results show that the proposed topology offers an excellent steady-state response, fast dynamic response, perfect and robust tracking of the maximum power point during partial shading condition.

Research paper thumbnail of Optimal placement and sizing of FACTS devices based on Autonomous Groups Particle Swarm Optimization technique

Archives of Electrical Engineering, 2021

This paper presents the application of Flexible Alternating Current Transmission System (FACTS) d... more This paper presents the application of Flexible Alternating Current Transmission System (FACTS) devices based on heuristic algorithms in power systems. The work proposes the Autonomous Groups Particle Swarm Optimization (AGPSO) approach for the optimal placement and sizing of the Static Var Compensator (SVC) to minimize the total active power losses in transmission lines. A comparative study is conducted with other heuristic optimization algorithms such as Particle Swarm Optimization (PSO), Timevarying Acceleration Coefficients PSO (TACPSO), Improved PSO (IPSO), Modified PSO (MPSO), and Moth-Flam Optimization (MFO) algorithms to confirm the efficacy of the proposed algorithm. Computer simulations have been carried out on MATLAB with the MATPOWER additional package to evaluate the performance of the AGPSO algorithm on the IEEE 14 and 30 bus systems. The simulation results show that the proposed algorithm offers the best performance among all algorithms with the lowest active power losses and the highest convergence rate.

Research paper thumbnail of Optimal operation of a hybrid-energy microgrid with energy storage system

E3S Web of Conferences, 2019

In this paper, a day-ahead profit-maximizing energy management scheme for a grid-tied microgrid o... more In this paper, a day-ahead profit-maximizing energy management scheme for a grid-tied microgrid operation is proposed. The microgrid contains various types of distributed energy resources (DERs) and an inverter-interfaced battery-bank storage system. The average of day-ahead hourly forecasted data for loads, wind speed, and solar radiation are inputted into the framework of energy management (EMF). To optimize the microgrid performance, EMF determines the hourly dispatch of reactive and active power for each DER. Also, it specifies the discharging and charging times of the energy storage system and the onload tap changer position setting of the transformer connected to the main grid. The main aim is to maximize the revenue of microgrid meeting all technical limitations. The main grid can sell/buy reactive and active powers to/from the microgrid with a variable daily energy price of the market. A collective rule base-BAT algorithm is implemented as a solver of the energy management o...

Research paper thumbnail of Optimum Power Extraction from Non-Uniform Aged PV Array Using Current Collector Optimizer Topology

Elektrichestvo, 2019

Harsh outdoor operating circumstances of photovoltaic (PV) array leads to non-uniform aging pheno... more Harsh outdoor operating circumstances of photovoltaic (PV) array leads to non-uniform aging phenomenon among PV panels which in turn reduces the life span of the PV modules and the energy efficiency of the whole array. Under non-uniform aging conditions for series-parallel (SP) connected PV modules, the characteristics of the entire PV array are deformed resulting in multiple peaks where one of them is the global peak. The appearance of such multiple peaks can mislead traditional maximum power point tracking (MPPT) techniques to get trapped at local peaks, which leads to misleading power losses. This paper proposes a current collector optimizer (CCO) topology to extract maximum power from a non-uniform aged PV array. By using CCO topology, the PV array characteristics have a unique maximum power point (MPP) which easy to follow by a simple MPPT algorithm. Consequently, the proposed topology does not suffer from misleading power losses. Besides, the CCO topology requires offline rearrangement of aged modules to obtain the optimal maximum power. A comparative study is conducted to demonstrate the efficacy of the proposed topology. Ultimately, the paper presents an offline algorithm for rearranging erratic aged CCO modules to extract the optimum power from large-scale PV arrays.