- Professor of Electrical Power Systems and the head of Electrical Power Engineering at Egypt-Japan University of Scie... moreProfessor of Electrical Power Systems and the head of Electrical Power Engineering at Egypt-Japan University of Science and Technology (E-JUST). Research interests include Power System Analysis and Control, Renewable Energy Systems, Energy Markets, Smart Grids, Internet of Things and related areas.(Professor of Electrical Power Systems and the head of Electrical Power Engineering at Egypt-Japan University of Science and Technology (E-JUST). Research interests include Power System Analysis and Control, Renewable Energy Systems, Energy Markets, Smart Grids, Internet of Things and related areas.)edit
This paper presents a new method for transmission loss allocation. The method is based on tracing the complex power flow through the network and determining the share of each load on the flow and losses though each line. Transmission... more
This paper presents a new method for transmission loss allocation. The method is based on tracing the complex power flow through the network and determining the share of each load on the flow and losses though each line. Transmission losses are taken into consideration during power flow tracing. Unbundling line losses is carried out using an equation, which have a
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This paper presents a model for the determination of the Wind Energy Conversion System (WECS) availability taking into consideration the dependence of WECS failure rate on wind speed. The proposed model takes into account the randomness... more
This paper presents a model for the determination of the Wind Energy Conversion System (WECS) availability taking into consideration the dependence of WECS failure rate on wind speed. The proposed model takes into account the randomness of wind speed as a stochastic Markov process presented by a transition matrix. The elements of this matrix are the transition rates between wind speed classes. Such a representation enables the building of a state diagram in which the dependence of failure rate on wind speed can be incorporated. Applications of the model to determining the WECS availability as well as the storage capacity required for maintaining a desired firm capacity level are illustrated using one year of hourly wind speed data records.
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AbstractThis paper proposes a novel method for transmission loss allocation in restructured power systems. It is based on circuit laws and the orthogonal projection theory. In this method, the current flow in each branch is divided into... more
AbstractThis paper proposes a novel method for transmission loss allocation in restructured power systems. It is based on circuit laws and the orthogonal projection theory. In this method, the current flow in each branch is divided into two components. The first one is due to the power transfer from generators to loads. The second component is due to the voltage differences between generators’ buses. The later currents are called no-load or circulating currents. These two current components are computed by using the superposition principle. The contribution of each load and generator to power losses in each branch of the network is derived analytically. Hence, the share of each load or generator in the overall transmission network losses is estimated. Furthermore, the impact of bilateral and multilateral contracts is incorporated in the power loss allocation algorithm. The contribution of each contract to the total transmission system power loss is estimated accurately. The method also takes into account ...
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Due to deregulation of the power supply industry and the continuing need for network expansion, there is pressure to maximise utilisation of the existing transmission and distribution networks. A way of achieving this is to employ dynamic... more
Due to deregulation of the power supply industry and the continuing need for network expansion, there is pressure to maximise utilisation of the existing transmission and distribution networks. A way of achieving this is to employ dynamic line ratings instead of the present static line ratings based on conservative weather assumptions. Such an approach is especially beneficial in areas of
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Power systems have expanded with a large development in smart grid solutions to maintain system stability. Monitoring of the present state of the power system including the phase angles of the bus voltages at critical buses in a... more
Power systems have expanded with a large development in smart grid solutions to maintain system stability. Monitoring of the present state of the power system including the phase angles of the bus voltages at critical buses in a particular time-synchronized way seems easier using phasor measurement units along with modern communication technology. In This paper, an algorithm to detect the evolution of angle instability phenomenon is proposed so that appropriate preventive actions can be started to avoid islanding. To mitigate instability, the mentioned algorithm with the controller detect the separation of internal machine rotor angles from system central angle automatically using phasor measurement units and also forward corrective action scheme (CAS) in case of the fast rate of change of the internal machine rotor angle. The corrective action scheme (CAS) such as tripping unstable generators is initiated in the accelerating part of the system when necessary and also under frequency load shedding actions are initiated in the decelerating part of the system whenever necessary.
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Changes are being implemented in the electrical power grid to accommodate the increased penetration of renewable energy sources interfaced with grid-connected inverters. The grid-forming (GFM) control paradigm of inverters in active power... more
Changes are being implemented in the electrical power grid to accommodate the increased penetration of renewable energy sources interfaced with grid-connected inverters. The grid-forming (GFM) control paradigm of inverters in active power grids has emerged as a technique through which to tackle the effects of the diminishing dominance of synchronous generators (SGs) and is preferred to the grid-following (GFL) control for providing system control and stability in converter-dominated grids. Therefore, the development of the GFM control is important as the grid advances towards 100% inverter-based grids. In this paper, therefore, we aim to review the changing grid scenario; the behaviour of grid-connected inverter control paradigms and major GFM inverter controls, including their modifications to tackle low inertia, reduced power quality, fault-ride through capability, and reduced stability; and the state-of-the-art GFM models that are pushing the universality of GFM inverter control.
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This work introduces a new inverter control strategy for a hybrid and autonomous microgrid structure by inserting a virtual inductive impedance loop in a droop control strategy to provide a reference voltage for the current and voltage... more
This work introduces a new inverter control strategy for a hybrid and autonomous microgrid structure by inserting a virtual inductive impedance loop in a droop control strategy to provide a reference voltage for the current and voltage loops of a DC voltage controller, thereby providing an optimal value to maintain the system voltage stability. This increases the renewable energy penetration of wind and solar on the microgrid and enhances conventional control by meeting the reactive power demand of the system while ensuring both DC and AC voltage regulation. A filter is designed for the system, and the control approach is theoretically analysed. Simulation models were constructed and implemented under different operation modes of load changes and source unavailability in MATLAB/Simulink. When analysed, the results suggest that the control approach can achieve desirable efficiency of power control and reliability of the proposed microgrid, hence reducing the burden on conventional generation and the utility grid.
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This paper presents a new method for calculating the individual generators’ shares in line flows, line losses and loads. The method is described and illustrated on active power flows, but it can be applied in the same way to reactive... more
This paper presents a new method for calculating the individual generators’ shares in line flows, line losses and loads. The method is described and illustrated on active power flows, but it can be applied in the same way to reactive power flows.Starting from a power flow solution, the line flow matrix is formed. This matrix is used for identifying node types, tracing the power flow from generators downstream to loads, and to determine generators’ participation factors to lines and loads. Neither exhaustive search nor matrix inversion is required. Hence, the method is claimed to be the least computationally demanding amongst all of the similar methods.The paper also shows how loop flows, if there is any, can be detected and handled.
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This paper presents a new method for calculating the individual generators’ shares in line flows, line losses and loads. The method is described and illustrated on active power flows, but it can be applied in the same way to reactive... more
This paper presents a new method for calculating the individual generators’ shares in line flows, line losses and loads. The method is described and illustrated on active power flows, but it can be applied in the same way to reactive power flows.Starting from a power flow solution, the line flow matrix is formed. This matrix is used for identifying node
Research Interests: Applied Mathematics, Computer Science, Signal Processing, Open Access, Control and Optimization, and 10 moreModelling and simulation, Matrix Inversion, Reactive Power, Tracing, Energy Markets, Information Systems Development And Management, Power flow, Electrical And Electronic Engineering, Exhaustive Search, and Automatic Control and Systems Engineering
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This paper proposed methods of maximizing the benefits of storage and diesel generator connected to a standalone microgrid. The analysis is based on the effects of site and size factors on the number of times diesel generator starts.... more
This paper proposed methods of maximizing the benefits of storage and diesel generator connected to a standalone microgrid. The analysis is based on the effects of site and size factors on the number of times diesel generator starts. Markov technique has been used for the analysis of the output powers of the WECS and SECS. The proposed method has been tested by increasing the rated power of the WECS and SECS by 25, 50, 75 and 100 %. The results have shown a decreased in the number of times a diesel generator starts by 2, 7, 9 and 9 % for WECS. Similarly, SECS decreased same by 4, 8, 11, and 13 %. Also, study of wind generator parameter at different cut-in-speeds levels, including 2, 2.5, 3.5 and 4 m/s reduced the number of times a diesel generator start by 122, 147, 116 and 134. In addition, the influences of storage and weather on the availability of system have also been investigated using Variable Boolean Logic Driven Markov process. In this case, the results have shown adding storage system; increased the microgrid availability by 0.058. In the same way, neglecting weather factor overestimate the system availability by 0.0104. Also, increasing the rated power of the WECS is the best way of maximizing the BCR of the system.
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The power sharing need and operational reliability of a renewable hybrid microgrid are addressed in this study. A hybrid microgrid allows for the flexible incorporation of renewable energy sources, overcoming the limitations of AC and DC... more
The power sharing need and operational reliability of a renewable hybrid microgrid are addressed in this study. A hybrid microgrid allows for the flexible incorporation of renewable energy sources, overcoming the limitations of AC and DC microgrids in terms of conversion losses and efficiency. To ensure optimal system performance, an interlinking converter (IC) is necessary for the seamless transmission of electric power between the two subgrids while keeping a stable DC bus voltage and appropriate AC sub-grid frequency. In this study, a Quasi Zsource converter (qZSC) with integrated boost capability is introduced as an IC in a PV-Wind based hybrid microgrid. Also, an adaptive dual loop based-PI (ADL-PI) control is proposed which maintains a constant peak DC-link voltage and supports maximum power point tracking while improving the system's overall stability. The proposed system and control approach are assessed using MATLAB/Simulink, and the results indicate its efficacy under ...
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This paper presents analyses of the model for the optimum design of standalone hybrid microgrid. The model is developed with the aim of optimizing system component sizing that can reliably satisfy isolated loads. The objective function is... more
This paper presents analyses of the model for the optimum design of standalone hybrid microgrid. The model is developed with the aim of optimizing system component sizing that can reliably satisfy isolated loads. The objective function is to minimize the annual cost of the plant while taking all constraints into consideration. Mixed integer linear programming technique is used to solve the optimization problem. By applying some approximations, the output power of the wind energy conversion system is expressed as a linear function of wind speed. Effects of different PV technologies and the rated power of each unit have been investigated. The results have shown the ability of the proposed model by reducing the cost of energy by 89.35%, 90.26%, 88.3530%, and 89.99% for AP120, ASE 300, KC120 and SAPC165 respectively. In the same way the carbon dioxide emission is reduced by 83%, 82.82%, 82.51% and 73.48 in the same order of the PV modules. Also, the optimal design is sensitive to the ra...
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This paper has presented a comprehensive review in the area of microgrid from the design to implementation. The aim is to evaluate the current status, problems and research efforts toward realising functional microgrids in the power... more
This paper has presented a comprehensive review in the area of microgrid from the design to implementation. The aim is to evaluate the current status, problems and research efforts toward realising functional microgrids in the power system. The expectations about microgrid are many; therefore the study is divided into three main sections. Recent advancements in the wind energy, solar energy and their future prediction are summarised. States of arts in optimum design of renewable energy microgrid are also investigated. In addition, critical literature review in the reliability analysis of microgrids consisting of renewable energy sources is also reported. Control of microgrids consisting renewable energy sources have been presented. Some examples of existing microgrids across the globe are critically reviewed. The work therefore recommends that energy planners and all stakeholders should consider environmental and regional difference in microgrids planning. Finally, future research a...
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Research Interests: Engineering, Renewable Energy, Solar, Optimization, Wind, and 2 moreStorage and Diesel Generator(Storage and Diesel Generator)
(Storage and Diesel Generator)
In this paper a new methodology is proposed to investigate the impacts of network structure on the optimum design of microgrids. The proposed microgrid consists of PV, wind, battery storage and diesel generator. By introducing some... more
In this paper a new methodology is proposed to investigate the impacts of network structure on the optimum design of microgrids. The proposed microgrid consists of PV, wind, battery storage and diesel generator. By introducing some approximations the relationships between wind turbine and PV module were expressed as linear functions of wind speed and solar radiation respectively. Therefore, the problem is formulated as a linear optimization problem that minimized the annual cost of the system. A computer program is developed in Matlab to formulate the optimization problem. Output of the optimization procedure show the viability of the proposed method by reducing the carbon emission by 70.40 % compared to operating the system on diesel generator alone. The result also shows that DC and AC coupled microgrid could reduce the system annual cost of hybrid microgrid by 5 and 2.8 % respectively. In addition, the effects of diesel prices, battery storage parameter, storage technology on the optimum system configurations have been investigated.
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ABSTRACT This paper presents a new method for accommodating loop flow in the process of transmission loss allocation including a generalised model for the transmission line. The developed line model is similar to the generalised circuit... more
ABSTRACT This paper presents a new method for accommodating loop flow in the process of transmission loss allocation including a generalised model for the transmission line. The developed line model is similar to the generalised circuit model based on the famous ABCD parameters. The proposed model enables unbundling the active power loss allocated to a node into two components; the first is the loss due to active power flow and the second is the loss due to reactive power flow. The same is done for the reactive power loss. Such separation of loss components makes loss allocation more transparent and explainable. In the presence of a loop flow, the power flow tracing algorithm gets faced with some nodes remaining in the system where no one of it is a pure sink node and hence gets stuck. The paper describes a method for loss allocation in the presence of loop flows based on signal flow graph manipulation techniques.
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The integration of demand response programs (DRPs) into the energy management (EM) system of microgrids (MGs) helps in improving the load characteristics by allowing consumers to interoperate for achieving techno-economic advantages. In... more
The integration of demand response programs (DRPs) into the energy management (EM) system of microgrids (MGs) helps in improving the load characteristics by allowing consumers to interoperate for achieving techno-economic advantages. In this paper, an improved algorithm is called LINFO is proposed for modifying search ability of the original weIghted meaN oF vectOrs (INFO) algorithm as well as avoiding its weaknesses like trapping in a local optima. The improved algorithm's efficiency is confirmed by comparing its results with those obtained by the original INFO and other optimization techniques using different standard benchmark test functions. Moreover, this improved algorithm and the original version are applied for solving the EM problem with the aim of optimizing the operation cost of the MGs in the presence DRPs. They are used to solve day-ahead EM problem for optimal operation of renewable energy resources, the optimal generation from a conventional diesel engines (DEs); ...
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Solving the energy management (EM) problem in microgrids with the incorporation of demand response programs helps in achieving technical and economic advantages and enhancing the load curve characteristics. The EM problem, with its large... more
Solving the energy management (EM) problem in microgrids with the incorporation of demand response programs helps in achieving technical and economic advantages and enhancing the load curve characteristics. The EM problem, with its large number of constraints, is considered as a nonlinear optimization problem. Artificial rabbits optimization has an exceptional performance, however there is no single algorithm can solve all engineering problem. So, this paper proposes a modified version of artificial rabbits optimization algorithm, called QARO, by quantum mechanics based on Monte Carlo method to determine the optimal scheduling for MG resources effectively. The main objective is minimization of the daily operating cost with the maximization of MG operator (MGO) benefit. The operating cost includes the conventional diesel generator operating cost and the cost of power transactions with the grid. The performance of the proposed algorithm is assessed using different standard benchmark t...
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This paper presents a new method for transmission loss allocation. The method is based on tracing the complex power flow through the network and determining the share of each load on the flow and losses through each line. Transmission... more
This paper presents a new method for transmission loss allocation. The method is based on tracing the complex power flow through the network and determining the share of each load on the flow and losses through each line. Transmission losses are taken into consideration during power flow tracing. Unbundling line losses is carried out using an equation, which has a
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Recently, Microgrids (MGs) have received great attention for solving power system problems, due to their low environmental effects and their economic benefits. This paper proposes a new application of an effective metaheuristic... more
Recently, Microgrids (MGs) have received great attention for solving power system problems, due to their low environmental effects and their economic benefits. This paper proposes a new application of an effective metaheuristic optimization method, namely, Honey Badger Algorithm (HBA), to solve energy management for optimal dispatch of the gridconnected MG incorporating Demand Response programs (DRP). Honey badger algorithm is used to solve an incentive DRP, with the aim of minimizing the total cost, which includes conventional generators fuel cost and the cost of power transaction with the main grid considering the load demand. In this paper, two case studies are conducted using HBA and simulation results are compared with those obtained by other algorithms (particle swarm optimization and JAYA algorithm). First case consists of three diesel generators, a PV generator and a wind generator. To prove the scalability of the HBA, the second case, which is much larger, is tested. Simula...
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Fault ride through (FRT) capability is one of the challenges faced in today's large-scale grid photovoltaic (PV) power system. Solar PV systems are designed to disconnect, and remain offline for 5 mints when tripped by loss of grid... more
Fault ride through (FRT) capability is one of the challenges faced in today's large-scale grid photovoltaic (PV) power system. Solar PV systems are designed to disconnect, and remain offline for 5 mints when tripped by loss of grid voltage. However, The PV system, by itself, cannot differentiate between transient and sustained grid voltage loss. It behaves in the same manner in the two cases, i.e., disconnect, stay offline for five minutes and then makes reconnection trial. Staying offline for five minutes unnecessarily wastes considerable amount of clean energy from the PV, may affect the power balance of the grid and many other adverse effects of service discontinuity This paper presents a new control strategy for grid FRT capability of a large grid connected PV System to increase the stability and reliability of the PV system, in which a photovoltaic inverter can be controlled to pass transient faults. Our strategy is to control the inverter so that it disconnects from the gr...
In this paper, effects of storage and diesel generator on the availability hybrid renewable energy microgrid have been investigated. Markov technique has been used for the analysis of the output powers of the wind energy conversion system... more
In this paper, effects of storage and diesel generator on the availability hybrid renewable energy microgrid have been investigated. Markov technique has been used for the analysis of the output powers of the wind energy conversion system (WECS) and solar energy conversion system (SECS).The proposed method has been tested by increasing the rated power of the WECS and SECS by 25 %, 50%, 75% and 100%. The results have shown a decreased in the number of times a diesel generator starts by 2 %, 7%, 9% and 9 % for WECS. Similarly, SECS decreased same by 4 %, 8 %, 11%, and 13 %. Also, the study of wind generator parameter at different cut-in-speeds levels, including 2 m/s, 2.5m/s, 3.5m/s and 4 m/s reduced the number of times a diesel generator start by 122, 147, 116 and 134. In addition, the effects of weather on the availability of system have been investigated using Boolean Logic Driven Markov process. In the same way, neglecting weather factor overestimate the system availability by 3.5...
With the increased demand for electrical power, it is required to increase the number of power transformers in power systems. One of the main challenges facing protection engineers is the protection and isolation of power transformers in... more
With the increased demand for electrical power, it is required to increase the number of power transformers in power systems. One of the main challenges facing protection engineers is the protection and isolation of power transformers in the shortest time possible, during internal faults. One of the alternative solutions to reduce the fault current in the power system is the application of a superconductor fault current limiter (SFCL). In this article, the ratios-based transformer differential protection algorithm is evaluated in the presence of resistive SFCL during internal fault conditions. A model of the system under study, including SFCL, is simulated and studies are performed in MATLAB/Simulink environment. The results demonstrate the capability of the ratios-based differential protection scheme to detect internal faults in the presence of SFCL.