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2021
El-Sayed, L. M. A., D. K. Ibrahim, M. I. gilany, and A. ’F. El’Gharably, "An Accurate Technique for Supervising Distance Relays during Power Swing", Indonesian Journal of Electrical Engineering and Computer Science, vol. 21, issue 3, pp. 1279-1290, 2021. AbstractWebsite

Power swing is a power system transient phenomenon that arises due to several reasons including line switching, line outage, sudden increment or decrement in load, faults, etc. Unnecessary tripping during power swing and unnecessary blocking for faults occur during power swing result in distance relay maloperation. Several cascaded outages and major worldwide blackouts have occurred due to maloperation of distance relays. This paper proposes a technique for supervising distance relays during power swing. The proposed
online technique discriminates real faults and power swing accurately. It relies on constructing a locus diagram for the current and voltage differences (ΔI-ΔV) between the two ends of the protected line. The locus is estimated at every power frequency cycle to continuously monitor the state of the line by utilizing the synchrophasor measurements at the sending and receiving ends of the line. The proposed technique is tested for two-area, four-machine power system under faults at different locations of zone-1 and zone-2 regions of distance relays, fault resistances, fault inception angles and slip frequencies using MATLAB software. The simulation results proved the superior improvement of distance relay performance for handling power swing blocking and unblocking actions.

Abo-Hamad, G. M., D. K. Ibrahim, E. A. M. Zahab, and A. F. Zobaa, "Adaptive Mho Distance Protection for Interconnected Transmission Lines Compensated with Thyristor Controlled Series Capacitor", Energies , vol. 14, pp. Article 2477, 2021. Abstract

This paper proposes an adaptive dynamic Mho distance relay based on a phase comparator scheme for protecting interconnected transmission networks compensated with a Thyristor Controlled Series Capacitor (TCSC). The proposed relay uses an impedance index factor to initiate the fault detection subroutine. The RMS of the positive sequence current of the faulted loop and the TCSC terminal current are compared for TCSC zone identification. A phase comparator for ground and phase distance elements is proposed, relying on the positive sequence voltage as a polarized memory quantity, while the operating and polarizing quantities are developed using estimated TCSC impedance to mitigate its negative impact. The proposed scheme is easy in implementation and independent on synchronized data transfer, as minimum communication requirements are needed. To evaluate the performance of the proposed scheme, extensive simulation studies were carried out on an IEEE9 bus system compensated with TCSC for different firing angles covering four modes of TCSC operations, different fault types, and fault locations. In addition, an IEEE-39 bus network, as a large interconnected system, is tested for validation purposes. The achieved results designate the precision of the proposed scheme. Moreover, the results indicate its effectiveness for fault resistance tolerance, close-in three phase faults, and stable power swing phenomenon compared with conventional relays.

Atta, M. E. E. - D., D. K. Ibrahim, and M. Gilany, "Broken Bar Faults Detection under Induction Motor Starting Conditions Using the Optimized Stockwell Transform and Adaptive Time-Frequency Filter", IEEE Transactions on Instrumentation and Measurement, vol. 70, pp. Article 3518110, 2021. Abstract

Most of the published research studies for detecting induction motor broken bar faults (BBFs) use a time–frequency (t − f ) decomposition tool to characterize the fault-related components. However, the identification and the assessment of these components in (t − f ) domain require skilled user or powerful pattern recognition technique. Moreover, a relatively long starting duration is necessary. This article introduces an automated scheme to detect BBFs and distinguish fault severity in induction motors under startup conditions regardless of the user experience and even under short starting duration and in a noisy environment. This scheme is based on the analysis of the starting current using optimized Stockwell transform (ST). An active set algorithm is applied to maximize the energy concentration of the left-side harmonic (LSH) component. Then, an adaptive time–frequency filter is applied to extract the LSH component from the (t − f ) domain, where the energy of the right part of LSH (RLSH) is utilized as an effective index for BBFs detection and for discriminating BBFs severity. Both real experimental data and simulation-based tests on 0.746- and 11-kW motors are used to extensively verify the performance of the proposed scheme. The achieved results have ensured that the proposed scheme can achieve a high accuracy with the minimum data and shortest acquisition time in comparison with some recent methods in the literature.

MOHAMED, A. H. M. E. D. A. B. D. E. L. R. A. H. M. A. N., H. Mohamed Sharaf, and D. K. Ibrahim, "Enhancing Distance Protection of Long Transmission Lines Compensated with TCSC and Connected With Wind Power", IEEE Access, vol. 9, pp. 46717 - 46730, 2021. Abstract

Thyristor controlled series compensation (TCSC) is widely used in long transmission lines to mainly improve power transfer capability. However, TCSC produces complicated impedance that negatively affects distance protection operation. The wind energy generation system produces additional complexity to the distance protection performance due to the variation of wind speed and fault current level. This paper proposes an integrated scheme to change adaptively the settings of the Mho distance protection by shifting the relay characteristics considering the bad impacts of TCSC, wind power and fault resistance. The proposed scheme achieves its main stages starting from fault detection, until relay tripping decision procedure including online estimation for preliminary fault location, impedance of TCSC and fault resistance using limited communication requirements. By extensive MATLAB simulations, the performance of the proposed scheme is examined compared with the conventional Mho relays under different fault locations, fault inception angle, fault resistance, different wind power penetration, different wind speeds and different TCSC ring angles. The achieved results ensured that the proposed scheme improves significantly Mho distance relay operation and avoids under-reaching and over-reaching problems irrespective of the large shunt capacitance along the transmission line, and also without identifying the parameters of TCSC such as the capacitance, the inductance or the ring angle.

2020
Rashad, B. A. - E., D. K. Ibrahim, M. I. Gilany, and A. ’F. El’Gharably, "Adaptive Single-End Transient-based Scheme for Detection and Location of Open Conductor Faults in HV Transmission Lines", Electric Power Systems Research, vol. 182, issue May 2020, pp. Article 106252, 2020. Abstract

Detection and location of open conductor in transmission systems using single-end data is a challenging task. This paper proposes a novel integrated scheme to detect and locate different types of open conductor faults (OCFs) in HV transmission systems. The proposed scheme unit (PSU) applies Discrete Wavelet Transform (DWT) with single-level decomposition on local current signals to detect OCFs correctly using adaptively estimated threshold values. PSU is also capable of dealing correctly with various normal transient conditions such as load capacitor switching. To ensure quick repair of OCFs, PSU captures the transient voltage surges and applies a fault location scheme using DWT and Clark Transformation to accurately estimate the location of different OCFs types. Extensive ATP simulations are employed to check the PSU performance under various OCFs conditions on a 345 kV, 100 km transmission line. The achieved results confirm the effectiveness, robustness, and reliability of PSU in detecting correctly OCFs as well as the low-impedance faults within only 1.25 cycles. Moreover, the percentage error in estimating OCFs location is less than 1%. PSU has also confirmed its capability to be applied in cascaded lines without any communication or synchronization between PSUs.

Ibrahim, D. K., G. M. Abo-Hamad, A. E. E. M. Zahab, and A. F. Zobaa, "Comprehensive Analysis of the Impact of the TCSC on Distance Relays in Interconnected Transmission Networks", IEEE Access, vol. 8, pp. 228315 – 228325, 2020. Abstract

This article extensively investigates the calculations of the compensation factor of the thyristor-controlled series compensator (TCSC), which are used to accurately evaluate the negative impacts of the TCSC on the performance of conventional distance relays. To broadly evaluate the distance protection performance, the TCSC was adapted to the IEEE 9-bus system as one of the interconnected transmission networks that are increasingly spreading to improve service reliability, reduce reserve capacity, and enhance system efciency. In addition, IEEE 39-bus system, as a large interconnected system, is also examined to generalize the TCSC impact on different interconnected systems. To determine the precise impact, the impedance of the TCSC was calculated based on its practical design parameters. The impedance of the TCSC was examined as a function of transmission line impedance and ring angle. Both Mho and Quadrilateral distance relays were tested using the MATLAB/Simulink environment for different types of faults, fault locations, fault resistances, and ring angles for capacitive, inductive, and blocking modes of TCSC operation. In addition, distance relay performance was evaluated during power swing phenomenon in the presence of the TCSC. Simulation tests indicated the negative impacts of the TCSC on distance relay operation, which are not limited to over-reach and under-reach in faulty conditions but also to maloperation in dynamic disturbances that cause power swing phenomena on the protected line.

fatma elzahraa magdy, D. K. Ibrahim, and W. Sabry, "Energy management of virtual power plants dependent on electro-economical model", Ain Shams Engineering Journal, vol. 11, issue 3, pp. 643-649, 2020. Abstract

From about two decades passed, a new expression was proposed for the first time: ‘‘Virtual Power Plants (VPPs)”. At this moment, a question was asked about if the VPPs can contribute as a trustworthy and environmentally oriented energy supply, or not? From this instant, over two hundred articles was presented for the management and optimal utilization of such a system, reliability and adaptation of VPP with the network connected to, retail and wholesale markets . . . etc. Most or approximately all articles intended with VPPs focused on studying VPPs from economical point of view only and did not studied the electrical and energy performance of VPPs. This paper represents a novel combined model for economical and electrical performances together of a generic VPP (GVPP); the electro-economical model (EEM). Two main targets are required from the proposed GVPP EEM: best performance and active network energy management of this GVPP. Also, a proposal for the first real case study in Egypt is taken under consideration: Siwa Oasis, Egypt. Siwa Oasis proposed VPP is modeled also with EEM. EEM for these two cases (GVPP and Siwa Oasis VPP) are simulated to obtain best performance and active network energy management for these VPPs. All data and results are stated and discussed.

Shafei, M. A. R., A. N. A. Alzaher, and D. K. Ibrahim, "Enhancing load frequency control of multi-area multi-sources power system with renewable units and including nonlinearities", Indonesian Journal of Electrical Engineering and Computer Science, vol. 19, issue 1, pp. 109-118, 2020. Abstract

The foremost aims of the Load Frequency Control (LFC) is to maintain the frequency at nominal value and minimize the unscheduled tie line power flow between different control areas. The penetration of renewable energy sources into the grid is a recent challenge to the power system operators due to their different modelling rather than conventional units. In this paper, enhancing load frequency control of multi-area multi-sources power system with nonlinearities including renewable units is proposed using a new application of proportional–integral–derivative controller with proportional controller in the inner feedback loop, which is called as PID-P controller. To investigate the performance of the proposed controller, a thermal with reheater, hydro, wind and diesel power generation units with physical constraints such as governor dead band, generation rate constraint, time delay and boiler dynamics are considered. The proposed controller parameters are optimized using different heuristic optimization techniques such: Linearized Biogeography-Based Optimization technique, Biogeography-Based Optimization technique and Genetic Algorithm. The ability of the system to handle the large variation in load conditions, time delay, participation factors, and system parameters has been verified comprehensively.

Shafei, M. A. R., M. A. Tawfik, and D. K. Ibrahim, "Fuzzy control scheme for energy efficiency and demand management in airports using 3D simulator", Indonesian Journal of Electrical Engineering and Computer Science, vol. 20, issue 2, pp. 583-592, 2020. Abstract

As the building sector has the largest share of energy consumption in most countries of the world, this paper focused on the study of one of the most important of the buildings which are the airports. Airports can play a major role in reducing the burden on the electrical grid as they have several factors that make them optimum models for applying energy efficiency strategies. Accordingly, the contribution in this paper is achieved by applying a Fuzzy Logic Control (FLC) scheme to improve the energy efficiency of the Egyptian airports without compromising the comfort level of the occupants and validating the obtained results by the aid of ―DesignBuilder‖ software conducted with the ―EnergyPlus‖ simulator, which is a state-of-the-art 3D simulator tool for checking building energy, carbon, lighting, and comfort performance. The applied 3D simulator evaluates the impacts of implementing the proposed fuzzy control system instead of ON/OFF control schemes or Building Management System (BMS). In this context, case studies were conducted at three different Egyptian airports as a high, medium, and low occupancy level airports respectively to discuss the opportunities and challenges of applying the fuzzy logic scheme in airports according to the occupancy level.

Abdel-Aziz, M. M., M. I. gilany, D. K. Ibrahim, and A. F. Abdel-Rheem, "Islanding Detection Using Rate of Change of Zero Sequence of Second Harmonic Voltage", International Journal Of Renewable Energy Research, vol. 10, issue 2, pp. 1514-1524, 2020. Abstract

Integration of Distributed Generation (DG) on the power system networks causes several difficulties, especially for the system protection. One of the important problems associated with system protection is the islanding that takes place when a DG unit (or group of units) continues to energize a part of the load separated from the main utility. As a result, many obstacles occur such as voltage and frequency fluctuation, in addition to personnel safety problems during maintenance. In this paper, the islanding problem is discussed and also the previous islanding detection techniques are investigated to get an efficient technique for islanding detection. The proposed technique is based on estimating the Rate of Change of Zero Sequence of Second Harmonic Voltage at the Point of Common Coupling (PCC). The proposed technique is extensively tested for inverter-based DG includes wind turbines with double-fed induction generator (DFIG). The proposed technique could distinguish the islanding operation correctly within only one cycle without non-detection zone (NDZ). In addition, it could differentiate between the islanding operation at different values for active and reactive power mismatch. Several scenarios are tested such as normal load variation, capacitor switching and power quality disturbances like voltage sags and swells. Faults and outage of one of DGs are also tested.

Dawoud, M. A., D. K. Ibrahim, M. I. gilany, and A. F. Abdel-Rheem, "A Proposed Passive Islanding Detection Approach for Improving Protection Systems", International Journal of Renewable Energy Research, vol. 10, issue 4, pp. 1940-1950, 2020. Abstract

Integration of Distributed Generation (DG) on the power system networks causes several difficulties, especially for the system protection. One of the important problems associated with system protection is the islanding that takes place when a DG unit (or group of units) continues to energize a part of the load separated from the main utility. As a result, many obstacles occur such as voltage and frequency fluctuation, in addition to personnel safety problems during maintenance. In this paper, the islanding problem is discussed and also the previous islanding detection techniques are investigated to get an efficient technique for islanding detection. The proposed technique is based on estimating the Rate of Change of Zero Sequence of Second Harmonic Voltage at the Point of Common Coupling (PCC). The proposed technique is extensively tested for inverter-based DG includes wind turbines with double-fed induction generator (DFIG). The proposed technique could distinguish the islanding operation correctly within only one cycle without non-detection zone (NDZ). In addition, it could differentiate between the islanding operation at different values for active and reactive power mismatch. Several scenarios are tested such as normal load variation, capacitor switching and power quality disturbances like voltage sags and swells. Faults and outage of one of DGs are also tested.

Younis, R. A., D. K. Ibrahim, E. M.Aboul-Zahab, and A. ’fotouh El'Gharably, "Techno-economic investigation using several metaheuristic algorithms for optimal sizing of stand-alone microgrid incorporating hybrid renewable energy sources and hybrid energy storage system", International Journal on Energy Conversion (I.R.E.CON.), vol. 8, issue 4, pp. 141- 152, 2020. Abstract

Increasing energy demand worldwide has resulted in more penetration of renewable sources for developing non-polluted electric energy despite their prices are not economically competitive to traditional generation systems due to intermittent nature of renewable resources. Energy storage systems are used to counteract the intermittent nature of renewable sources. Therefore, the optimal sizing and design of stand-alone renewable generating systems is a significant concern to get a more cost-effective system. This paper focuses on achieving the optimum design and size of a microgrid to meet the load requirements and reducing the total cost including capital, investment, operational and maintenance costs. For this aim, the sizing problem is formulated to be solved using three well-known metaheuristic algorithms, namely, Particle Swarm Optimization (PSO), Grey Wolf Optimization (GWO) and Cuckoo Search Optimization (CSO). The employed microgrid comprises hybrid renewable energy sources of PV/Wind systems integrated with a hybrid energy storage system of Battery and FC/Electrolyzer set for supplying AC loads located in Zafarana, Egypt. On the basis of real meteorological data of the studied location, the produced energies from the renewable sources are estimated using MATLAB developed algorithms. The simulation results showed that the optimized design using CSO can robustly and efficiently yield the optimal design of a microgrid.

2019
Mohamed, M. S., M. A. R. Shafei, A. A. Mansour, and D. K. Ibrahim, "Coils design and parallel resonant H-bridge inverter for inductive power transfer to recharge low-power portable devices", 21st International Middle East Power Systems Conference, MEPCON , Tanta University, Egypt, December 17-19, 2019. Abstract

The capability of the inductive power transfer (IPT) for wireless charging mainly depends on both coil structure and inverter topology. The paper presents the resonant inverter based on the concept of energy injection and free oscillation which are applied to increase the resonant frequency without raising the switching frequency. The implemented inverter utilizes the variable frequency zero current switching (ZCS) control strategy for parallel configuration that ensure the high operating frequency at multiplies of the inverter switching frequency. Consequently, it will result in decreasing the inverter switching loss and also reducing the coil size that operates at resonant frequency. The coil design methodology is introduced in details while studying the different factors affecting the coil behavior. The performance of the overall designed system is evaluated via simulation tests carried out using ANSYS Maxwell and MATLAB SIMULINK.

Ahmed, M. A., D. K. Ibrahim, and M. Gilany, "Electric Spring Technology in Small Scale Residential Microgrid", 21st International Middle East Power Systems Conference, MEPCON, Tanta University, Egypt, December 17-19, 2019. Abstract

Energy communities worldwide and in Egypt specifically encourage the household customers toward the renewable energy investment by utilizing grid-connected renewable generators (i.e. PV and wind turbines). Grid stability and power quality become the major concerns for the grid operators as they are too much affected during the increasing penetration of distributed renewable generators and also the growth of non-linear loads at end users. Electric spring (ES) technology is recently applied as distributed voltage controllers intended to stabilize the electrical grid in the presence of the distributed generators and the non-linear loads of the consumers. Consumers' satisfaction towards the grid stability is very essential as most of the household applications include sensitive loads that require a clean power with definite voltage value. This paper analyzes and verifies the electric spring technology in a household application with a renewable energy investment through a grid-connected PV panel, while a standby diesel generator operates in case of utility failure. The proportional-integral (PI) controller of ES has been successfully optimized using a genetic algorithm. A developed MATLAB/SIMULINK model is tested under a real household loading curve, typical PV generation profile in sunny/cloudy days, dynamic response of the standby diesel generator, and the utility disturbances (i.e. voltage decrease, increase, and fluctuation). For all aforementioned tested disturbances, the ES has succeeded to stabilize the voltage for the household sensitive appliances (e.g. computers, TV, washing machine, etc.).

Afifi, M. K., H. M. Sharaf, M. M. Sayed, and D. K. Ibrahim, "Enhanced Two-Fault Point Multi-Objective Coordination Scheme for Directional Overcurrent Relays in Meshed Distribution", ", 21st International Middle East Power Systems Conference, MEPCON , Tanta University, Egypt, December 17-19, 2019. Abstract

in this paper, an enhanced directional overcurrent relays (DOCRs) coordination scheme is introduced. The proposed scheme considers the fault severity by applying weighting factors, calculated based on system fault currents at different locations in each relay zone of protection. This enhanced coordination reduces the operating time of the relays for severe fault currents avoiding the greater thermal and mechanical stresses that reduce equipment lifetime. The DOCRs coordination problem is formulated as a multi-objective optimization problem to accomplish better results than the single-objective methodology with respect to relays selectivity and speed. DOCRs coordination problem is solved using Goal Attainment method in MATLAB Optimization Toolbox. A two-fault point coordination scheme is applied to IEEE 14 bus system for both the conventional and the proposed scheme. The results are analyzed according to several system performance indices including: the mean of the system’s relays operating times, the maximum primary relay operating time, the maximum backup relay operating time and maximum coordination time interval (CTI) between primary/backup pairs. The achieved results indicated that the proposed scheme considering the severity weighting factors has reduced the mean operating time of relays especially for the relays with faults with high severity. It means more reliable, faster protection system with less thermal and mechanical stresses for system equipment.

Magdy, M., M. Elshahed, and D. K. Ibrahim, "Impacts of Distributed and Centralized Grid- Connected PV on Radial Distribution Networks", 21st International Middle East Power Systems Conference, MEPCON, Tanta University, Egypt, December 17-19, 2019. Abstract

This paper investigates the impacts of the centralized and distributed grid-connected photovoltaic systems on radial distribution networks. Different weather conditions are considered. Different PV penetration levels are investigated in both centralized and distributed PV configurations. Daily simulation is performed using the Open Distribution System Simulator (OpenDSS). The study will include the impacts on voltage magnitude, the voltage regulators, the voltage unbalance factor and losses during the day. The simulations results are presented in details and conclusions are drawn based on them.

Shafei, M. A. R., M. A. Tawfik, and D. K. Ibrahim, "Improving Energy Efficiency in Egyptian Airports: A Case Study of Sharm-Elshiekh Airport", 21st International Middle East Power Systems Conference, MEPCON, Tanta University, Egypt, December 17-19, 2019. Abstract

Airports can play a major role in reducing the burden on the national electric grid as they have several factors that make them optimum models for applying energy efficiency strategies. Accordingly, this paper presents a Dual-Dimension Strategy (DDS) to improve the energy efficiency in the airports. This strategy aims to study the opportunities of improving energy efficiency in a way that do not affect the comfort level of occupants, as well as studying the challenges of implementing PV power stations at or around the airports without affecting the safety of aviation. In this context, a case study was conducted at Sharm-Elshiekh airport as a high occupancy level airport to discuss the opportunities and challenges accompanied by the proposed strategy. The detailed simulation of the proposed strategy was carried out using the “DesignBuilder” software, which is automatically conducted with the “EnergyPlus” simulator. Results showed that airports have an opportunity to reduce its energy consumption by up to 25% monthly by using smart control systems such proposed fuzzy system. In addition, the implementation of PV stations in or round the airports can contribute in feeding the airports with a huge amount of clean energy according to the available space and the irradiation in the site of the airport. All of these results refer to save millions of carbon emissions which resulted from depending on fuel sources.

Shafei, M. A. R., Y. A. Anwar, and D. K. Ibrahim, "Sharm El-Sheikh 5 MW PV Plant Performance, Environmental Impact and Grid Connection Parameters", 21st International Middle East Power Systems Conference, MEPCON , Tanta University, Egypt, December 17-19, 2019. Abstract

A few years ago, most of photovoltaics (PV) were installed in rather small stand-alone systems, the majority of today´s modules are implemented in grid-connected systems satisfying well-defined technical aspects. This growth is mostly due to the ambitious subsidy programs adopted by governments in the developing countries. Meanwhile, to be successfully integrated with the utility grid in low, medium, or high voltage networks, it is essential to meet the requirements of the country interconnection code. In this paper, the requirements of the Egyptian grid code for connecting a 5 MW PV plant with utility grid have been examined and evaluated. In addition, the environmental effects of installing the PV plant have been discussed and compared with fossil fuels.

fatma elzahraa magdy, D. K. Ibrahim, and W. Sabry, "Virtual power plants novel electro-economical modeling approach", Cigre Egypt 2019, The Future of Electricity Grids: Challenges and Opportunities, Egypt, 6-8 March 2019. Abstract

From about fifteen years passed, a new term was proposed for the first time by Dielmann and Velden: "Virtual Power Plant (VPP)", and they asked about if the VPPs can contribute as a reliable and environmentally oriented energy supply, or not?, at this moment, they considered some problems that must be examined to insure the success of this idea; like: management of such a system (optimal utilization), adaptation of VPP with the network connected to (reliability), markets (retail and wholesale) … etc. If these problems are solved, then the VPP has a large opportunity to deliver an important contribution as an economic, reliable and nonpolluting energy supply system. The market is the dominant factor for the success of VPPs being. Before the age of distributed generation (DG), the energy delivery pricing model was the cost against service. The model states that consume (buy) energy then pay -buy and pay-. When the age of renewables raised up, the model of buy and pay is shifted away to a new market based pricing model: pay at first and then buy. Another conceptual model starts to appear including active demand side participation using the transactive energy concept. In this paper, a new combined model for market and electrical performance of VPPs is presented; the electro-economical model (EEM). The model will include the four basic components of any VPP: dispatchable power plants, flexible loads, storage units, and stochastic generating units. Two main targets for the proposed modeling: optimal operation of VPPs, and active network energy management of VPPs. The VPP can earn profit from the market and as a result, its objective reduces to maximizing its profit (ρ). Energy management in a VPP or active network management means the optimal operation of this VPP in order to manage energy flow. Optimal operation is based on a stochastic basis of energy sources and multi-market framework.

fatma elzahraa magdy, D. K. Ibrahim, and W. Sabry, "Virtual Power Plants Modeling and Simulation using Innovative Electro-Economical Concept", 16th International Conference on Electrical Machines, Drives and Power Systems ELMA , Varna, Bulgaria, 6-8 June 2019. Abstract

Most of the previous researches which intended with the subject of virtual power plants (VPPs), focused on the study of VPPs from economical point of view: auctions, bidding, trading, markets, pricing, cost, profit, benefits, risk, investors … etc. Merely conjecture, all the VPPs' models presented are financial and economical models, with no one prescribed electrical model. In this paper, a generic VPP will be proposed and considered for the study. The proposed generic VPP will be modeled with a novel Electro-Economical Model (EEM). The proposed model was constructed on three steps: construction of electrical model, construction of economical model, and combining both electrical and economical models to form EEM of the proposed generic VPP. The proposed generic VPP consisting of four basic components: dispatchable power plant(s), flexible load(s), storage unit(s), and stochastic generating unit(s); was illustrated. This system model has been simulated. All simulation results will be demonstrated and discussed.

Afifi, M. K., H. M. Sharaf, M. M. Sayed, and D. K. Ibrahim, "Comparative Study between Single-Objective and Multi-Objective Optimization Approaches for Directional Overcurrent Relays Coordination Considering Different Fault Locations", 13th IEEE PES PowerTech Conference, Milano, Italy, 23-27 June 2019. Abstract

In this paper, a comparative study of single-objective and multi-objective optimization approaches for directional overcurrent relays (DOCRs) coordination is presented. Singleobjective optimization approach is investigated using two methods; the fmincon function which is the gradient-based method, while the second method is the Genetic Algorithm which is a meta-heuristic technique. Multi-objective optimization approach is investigated using fmincon function and Goal Attainment method. All the methods are available in the MATLAB Optimization Toolbox. Different fault locations on the meshed power distribution network of the IEEE 14 bus system are considered for the investigated methods. The results of singleobjective and multi-objective approaches are compared regarding total relays operating times, mean fault clearing time, maximum primary and backup relays operating time and maximum coordination time interval. The results show that using the multi-objective optimization approach in solving the DOCRs coordination problem achieved less total relays operating time and coordination time intervals which ensure faster fault clearing.

Abdelbadea, M., T. A. Boghdady, and D. K. Ibrahim, "Enhancing active radial distribution networks by optimal sizing and placement of DGs using modified Crow Search Algorithm", Indonesian Journal of Electrical Engineering and Computer Science, vol. 16, issue 3, pp. 1179-1188, 2019. Abstract

Incorporating many Distributed Generators (DGs) technologies in power system networks has grown rapidly in recent years. Distributed generation (DG) plays a key role in reducing power loss and enhancing the voltage profile in radial distribution networks. However, inappropriate DGs site or size may cut network efficiency; moreover, injecting harmonics is one of the integration concerns of inverter-based DGs. Two-procedure based approach is introduced in this paper. The first procedure solves the DGs siting and sizing problem, as a multi-objective one by improving the voltage profile of the whole distribution network and also reducing its power loss. A weighted sum method is presented to create the Pareto optimal front in this procedure and get the compromised solution by applying a novel metaheuristic optimizer, named Crow Search Algorithm (CSA). A modification on CSA is also proposed and applied to improve its performance. The achieved solution for inverter-based DGs placement and size is checked in the second procedure to make sure the accepted voltage THD at all buses by implementing detailed simulation for the tested system using Matlab/Simulink. The proposed approach has been tested on IEEE 33-bus radial distribution system with photovoltaic DGs. To confirm the superiority of the modified CSA algorithm in terms of quality of solution, its achieved results are compared with the results offered by the original CSA algorithm and published results of some other nature-inspired algorithms.

Soliman, A., D. K. Ibrahim, and O. E. Gouda, "Parameters affecting the arcing time of HVDC circuit breakers using black box arc model", IET Generation, Transmission & Distribution, vol. 13, issue 4, pp. 461 – 467, 2019. AbstractWebsite

Arc interruption of high voltage direct current (HVDC) circuit breakers (CBs) is one of the main challenging factors for using HVDC grids. To evaluate the arc interrupting capability in HVDC CBs, black box arc models are used to represent the nonlinear arc conductance depending on Cassie and Mayr dynamic arc equations. Extensive simulation studies are carried out to investigate the effect of controlled and uncontrolled parameters on the CB arcing time. A real line represents a part of 500 kV electrical connection systems between Egypt and the Kingdom of Saudi Arabia is simulated to be a faulty load. It is found that the arcing time of the HVDC CB can be reduced by increasing the value of cooling power coefficient (p) and decreasing the value of arc time constant (τ). It is also deduced that the arcing time is reduced by the increase of the commutation capacitance value (C) and decreasing the commutation inductance (L) value and vice versa. Moreover, it is concluded that the arcing time is greatly affected by the fault location and the fault arc resistance (Rf) according to fault conditions.

Younis, R. A., D. K. Ibrahim, E. M.Aboul-Zahab, and A. ’fotouh El'Gharably, "Power Management Regulation Control Integrated with Demand Side Management for Stand-alone Hybrid Microgrid Considering Battery Degradation", International Journal of Renewable Energy Research, vol. 9, issue 4, pp. 1912-1923, 2019. AbstractWebsite

A new Power Management Regulation Control (PMRC) integrated with Demand Side Management (DSM) strategies is proposed to enhance the Energy Management System (EMS) of a stand-alone hybrid microgrid. The microgrid combines Wind and PV systems as Renewable Energy Sources (RES) with a hybrid Energy Storage System (ESS) of Battery and Fuel Cell/Electrolyzer set. Towards achieving Net Zero Energy Supply, such microgrid is adequate in remote and isolated new communities with AC controllable critical and noncritical loads. The proposed PMRC implies two-levels of control based on Multi-Agent System (MAS). The first level keeps the output power of each source in its maximum available output power by applying maximum power point tracking (MPPT) techniques. The second level is based on making proper decisions for achieving the power balancing regulation and coordination between the available and the reserve power of the RES and ESS under different operating modes. Valley Filling, Energy Conservation and Load Shifting are applied as DSM strategies to improve loads sustainability during system contingencies. Considering the battery as the most expensive part in the microgrid, the effectiveness of the proposed strategy is further verified by determining the maximum permissible estimated battery lifetime during the operation in all possible scenarios. Extensive simulation studies for various scenarios of microgrid operation in a year were carried out using Matlab/ Simulink with realistic typical wind speed, solar irradiation data and restricted by the status of available ESS.

Hamdy, M., M. Elshahed, D. Khalil, and E. E. - D. A. El-Zahab, "Stochastic Unit Commitment Incorporating Demand Side Management and Optimal Storage Capacity", Iranian Journal of Science and Technology, Transactions of Electrical Engineering, vol. 43, issue 1, pp. 559–571, 2019. AbstractWebsite

High penetration of wind energy imposes several operational challenges due to its uncertainty and intermittent nature. Flexible energy resources represent key solutions to compensate for power mismatch associated with wind power (WP) uncertainty and intermittency. This paper proposes a new stochastic unit commitment (SUC) problem formulation including high penetration of wind energy, energy storage system (ESS), and demand side management. Firstly, the Latin hypercube sampling is combined with Cholesky decomposition method to generate different WP scenarios. The simulated scenarios are then reduced using the fast forward selection algorithm. Finally, a novel SUC formulation implements these reduced scenarios to size the ESS optimally, considering its cost and benefit maximization of wind energy. To validate the proposed approach, a nine-unit test system is used to demonstrate the reduction in the operational cost and the increase in the utilized wind energy under different operational conditions.