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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.

Magdy, M., M. Elshahed, and D. K. Ibrahim, "Enhancing PV Hosting Capacity Using Smart Inverters and Time of Use Tariffs", Iranian Journal of Science and Technology, Transactions of Electrical Engineering, vol. 45, issue 3, pp. 905–920, 2021. Abstract

Optimizing the Photovoltaic (PV) hosting capacity (HC) considering the irradiance’s variability properly and the load during the day represents a critical matter. Typically, the high PV HC results in overvoltage and high voltage fluctuations at the point of common coupling (PCC) with the utility. In this paper, a new algorithm is proposed for enhancing PV HC by considering the smart inverter functions to overcome key PCC issues. The Volt-Var and dynamic reactive current functions of the smart inverter are suggested to increase the PV HC. Furthermore, the time of use tariff is utilized for mitigating the duck curve issue at the utility by reducing the peak to valley difference of the substation net load curve. Quasi-static timeseries simulations are performed using the OpenDSS program to prove the effectiveness of the proposed algorithm. The proposed algorithm is validated by extensive numerical analysis on the standard IEEE 123 node test feeder. Deduced outcomes are very encouraging in mitigating the overvoltage, reducing the energy losses, limiting the considerable number of on-load tap changes, and alleviating the high voltage fluctuations.

Khalil, E. A., T. a. Boghdady, M. H. Alham, and D. K. Ibrahim, "Enhancing the Conventional Controllers for Load Frequency Control of Isolated Microgrids Using Proposed Multi-Objective Formulation Via Artificial Rabbits Optimization Algorithm", IEEE Access, vol. 11, pp. 3472- 3493, 2023. AbstractWebsite

Isolated microgrids (IMGs) power remote areas. However, IMG may lower the frequency stability and increase frequency excursions with low system inertia. Load frequency management ensures system stability. Thus, the paper proposes a novel multi-objective tuning strategy to improve IMG's load frequency control (LFC) and take the microgrid controller's control signals into account. Diesel engine generator, fuel cell, battery energy storage system, and renewable energy sources (RESs) like photovoltaic and wind systems make up the IMG. Conventional controllers such as proportional-integral (PI) and proportional integral derivative (PID) are classically tuned based on the standard error criteria as a traditional single-objective tuning approach. Due to the low inertia of the system and the stochastic nature of RES, they cannot act as required under different operating scenarios. Therefore, the PI and PID controllers are tuned using the proposed multi-objective-based tuning approach to reduce the frequency deviations. In addition, anti-windup is applied to the enhanced classic controllers to keep them distant from the nonlinear zone and beyond the source's physical constraints. The proposed tuning process also considers the maximum practical generation rates for different sources. The recent Artificial Rabbits Optimization (ARO) algorithm is applied to simultaneously adjust the controller parameters for several controlled sources in IMG. Extensive simulations in MATLAB and Simulink confirm the effectiveness of the proposed approach to keep the system stable even when facing high levels of disturbances. In addition, accomplishing sensitivity analysis, severe +-25% changes to the system's parameters guarantee that the proposed tuning strategy keeps the system stable.

Fayez, K. M., M. A. R. Shafei, and D. K. Ibrahim, "Enhancing Thermal Performance and Lifetime Cycles of Li-ion Battery in Electric Vehicles", ”, International Journal of Renewable Energy Research, vol. 11, issue 3, pp. 1166-1177, 2021. Abstract

Hybrid energy storage system has essential priority in Electric Vehicle applications. Therefore, the design of an appropriate power sharing algorithm among energy storage components is necessary to improve battery thermal performance and provide extra extension of battery lifetime cycles. This paper presents an analytical study on the effect of using wavelet decomposition-based power sharing algorithm to force the high frequency component to be fed by the supercapacitor and accordingly reduces the thermal stress on the battery. The proposed approach was investigated by applying it on electric vehicle model in ADVISOR Tool/MATLAB using different driving profiles such as Urban Dynamometer Driving Schedule profile, Highway Fuel Economy Test, New York City Cycle, Los Angeles 1992 and new European driving cycle. The results declare that by using proposed power sharing algorithm, the working temperature of lithium battery decreases significantly while battery lifetime cycles increase, apparently. For urban dynamometer driving schedule, the operating temperature of lithium battery is improved much at maximum decomposition levels reaching to only 25.6 °C compared to 35 °C. In addition, the battery lifetime cycles increased from 2213 to 2585 cycles. Neural Networks pattern recognition tool is also applied to classify the driving cycle to the nearest reference cycles chosen to represent the different driving conditions which help to detect the appropriate wavelet decomposition level, achieving better battery thermal performance and battery lifetime cycles.

Al-Barashi, M. M., D. K. Ibrahim, and E. E. - D. A. El-Zahab, "Evaluating Connecting Al-Mukha New Wind Farm to Yemen Power System", International Journal of Electrical Energy, vol. 3, issue 2, pp. 57-67, 2015. AbstractWebsite

This paper presents modeling and impact analysis of Al-Mukha wind farm (MWF) on Yemen power system, which is made of thermal power plants. In this paper, four kinds of major components are modeled: a 60MW wind farm, a transmission network, thermal power plants, and the Yemen power system load. To analyze the impact of the wind power generation to the Yemen power system, simulations are carried out for two case studies by using the DIgSILENT program. The first is the case of grid impact studies: impact on thermal limits, voltage variations, and system stability, in which an aggregated model of the wind farm is used. The other is the dynamic performance of the wind farm by analyzing low-voltage ride through LVRT, harmonics and flicker impact on the basis of the detailed wind farm layout with 30 wind turbines (WTs) arranged in four stands and the external grid of 2175MVA short-circuit capacity. The simulation results show that the loading of most lines and voltage variations are slightly reduced. In addition, there is no harmful effect on the system stability and also the wind farm is capable to ride through the grid fault. Finally, it is shown that the wind farm contributes voltage and current harmonics higher than the permissible limits while the flicker levels are far below any critical values. 

Al-Barashi, M. M., D. K. Ibrahim, and E. E. - D. A. El-Zahab, "Evaluating The Energy System in Yemen", Journal of Electric Engineering, JEE, vol. 16, issue 1, pp. 338-342 (Article 16.1.41), 2016. AbstractWebsite

This paper presents a deep analysis for the energy system in Yemen, which consists of thermal power plants taking into account the strengths and weaknesses of its power system. The investigation results show that Yemen power system suffers lacking of energy efficiency (EE), weak institutional capacity, high losses in the generation, transmission and distribution grids, and currently the disability to invest in renewable energy (RE). Yemen should focus on foundational activities to build institutional capacity and mobilize resources to initiate suitable energy efficiency policies and measures. Yemen should also focus on exploring the opportunities of designing innovative energy systems based on decentralized small-scale power generation. Microgrids could enable power supply to remote areas at lower costs than required by traditional infrastructure.

Din, E. S. T. E., M. M. Abdel Aziz, M. Gilany, and D. K. Ibrahim, "Fault location scheme for combined overhead line with underground power cable", Electric power systems research, vol. 76, issue 11: Elsevier, pp. 928-935, 2006. AbstractWebsite

This paper presents a fault location scheme for transmission systems consisting of an overhead line combined with an underground power cable. The algorithm requires phasor measurements data from one end of the transmission line and the synchronized measurements at the most far end of the power cable. Fault location is derived using distributed line model, modal transformation theory and Discrete Fourier Transform. The technique can be used on-line or off-line using the data stored in the digital fault recording apparatuses. The proposed scheme has the ability to locate the fault whether it is in the overhead line or in the underground power cable. In addition to, the proposed scheme gives an accurate estimation of the fault resistance at fault location. Extensive simulation studies carried out using MATLAB show that the proposed scheme provides a high accuracy in fault location under various fault conditions.

Din, E. S. T. E., and D. K. Ibrahim, "A Fault Location Scheme for High Resistance Shunt/Series Faults in Radial Cable Systems", Scientific Bulletin of Faculty of Engineering, Ain Shams University, vol. 41, issue 2: ISSN 1110-1385, pp. 587-612, 2006. Abstract
Sabra, H., D. K. Ibrahim, and M. Gilany, "Field experience with sympathetic tripping in distribution networks: problems and Solutions", The journal of Engineering, IET, vol. 2018, issue 15, pp. 1181 – 1185, 2018. AbstractWebsite

Sympathetic tripping is a common challenge that affects the proper operation of the earth fault relays in distribution networks. It likely occurs when healthy feeders are exposed to an unnecessary trip operation in response to an actual fault occurring on an adjacent feeder. The sympathetic tripping phenomena of overcurrent and earth fault (EF) relays in the distribution networks and their causes are studied in this paper. Real recorded data of affected healthy feeder(s) for different sympathetic trip scenarios reported from an Egyptian distribution network are extensively analysed. A custom logic protection scheme is proposed to detect the sympathetic tripping phenomena using the existing features of IED relays without any additional cost. In addition to the captured real disturbance records, simulated scenarios of sympathetic tripping are modelled using MODELS language in ATP/EMTP program to evaluate the proposed schemes. The achieved results ensure the suitability of the proposed protection program in order to avoid the unnecessary false sympathetic tripping for both incoming and outgoing feeders.

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.

Rashad, B. A. - E., D. K. Ibrahim, M. I. Gilany, A. H. M. E. D. S. A. Y. E. D. ABDELHAMID, and W. Abdelfattah, "Identification of broken conductor faults in interconnected transmission systems based on discrete wavelet transform", PLoS ONE, vol. 19, issue 1, pp. e0296773, 2024. AbstractWebsite

Interconnected transmission systems are increasingly spreading out in HV networks to enhance system efficiency, decrease reserve capacity, and improve service reliability. However, the protection of multi-terminal lines against Broken Conductor Fault (BCF) imposes significant difficulties in such networks as the conventional distance relays cannot detect BCF, as the BCF is not associated with a significant increase in current or reduction in voltage. Traditionally, the earth fault relays in transmission lines may detect such fault; Nonetheless, it suffers from a long delay time. Moreover, many of the nearby earth fault relays detect the BCF causing unnecessary trips and badly affecting the system stability. In this article, a novel single-end scheme based on extracting transient features from current signals by discrete wavelet transform (DWT) is proposed for detecting BCFs in interconnected HV transmission systems. The suggested scheme unit (SSU) is capable of accurately detecting all types of BCFs and shunt high impedance faults (SHIFs). It also adaptively calculates the applied threshold values. The accurate selectivity in multi-terminal lines is achieved based on a fault directional element by analyzing transient power polarity. The SSU discriminates between internal/external faults effectively utilizing the time difference observed between the first spikes of aerial and ground modes in the current signals. Different fault scenarios have been simulated on the IEEE 9-Bus, 230 kV interconnected system. The achieved results confirm the effectiveness, robustness, and reliability of SSU in detecting correctly BCFs as well as the SHIFs within only 24.5 ms. The SSU has confirmed its capability to be implemented in interconnected systems without any requirement for communication or synchronization between the SSU installed in multi-terminal lines.

Ibrahim, D. K., A. F. Zobaa, E. A. El-Zahab, and G. M. Abo-Hamad, "Improving Mho and Quadrilateral Relays Performance during Power Swings", International Review of Electrical Engineering, vol. 5, issue 6: Praise Worthy Prize, FEDERICO II University 21 Claudio Naples I 80125 Italy, 2010. Abstract

Power swings, both stable and unstable, may precipitate wide spread outages to power systems with the result that cascade tripping of the power system elements occur. This paper deals with improving Mho and Quadrilateral relays performance under power swing conditions by discriminating between faults and power swings phenomenon. Distance relay may misinterpreted power swing as three-phase fault, but wavelet transform is able to discriminate clearly between power swings and faults. So, a logic block for fault detection based on the wavelet transform combined with the output of the conventional distance relay is proposed. Only voltage signals are used in wavelet relay to distinguish between fault and power swings conditions. The described scheme has been tested on a double line simulated power system using MatLab program.

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.

Saber, A. M., T. A. Boghdady, and D. K. Ibrahim, "Multi-objective Sizing of a Standalone Renewable Power System for Offshore Oil and Gas Applications", International Journal Of Renewable Energy Research, vol. 11, issue 4, pp. 1597-1608, 2021. Abstract

The potential of electrifying Offshore Oil and Gas platforms by Hybrid Renewable Energy Sources (HRESs) was paid attention to recently. As sensitive loads, these installations require a high level of reliability, which requires special consideration in modeling. This load sensitivity contradicts the intermittent nature of HRESs like winds and waves. Implementing batteries in a similar energy system could help decrease the variation in the generated power. However, practical batteries are known to degrade over many factors. In this article, a study is presented on quantifying the enhancement in the reliability of supply caused by coupling of a Wind-Wave (WW) hybrid offshore energy converter (named: HOEC) unit with a Lithium-Based Energy Storage System (LBESS), while considering LBESS’s degradation and load sensitivity, and optimizing the battery size and WW ratios. The optimization is solved using a semi-analytical approach and compared against two heuristic algorithms, which are particle swarm optimization and pattern search algorithm. Results demonstrate possible system reliability enhancement while optimizing the system designed using the proposed approach.

Ibrahim, D. K., E. E. D. A. El Zahab, and S. A. E. A. Mostafa, "New Coordination Approach to Minimize the Number of Re-adjusted Relays When Adding DGs in Interconnected Power Systems", Journal of Electrical Engineering & Technology (JEET), vol. 12, issue 2, pp. 502-512, 2017. AbstractWebsite

The presence of DGs in power system networks tends to negatively affect the protective relays coordination. The proposed method introduces an approach to minimize the numbers of relays that acquire new settings on contrary to their original settings (case without DG), to achieve relays coordination in case of adding DG, since relays coordination with minimum number of relays of readjusted settings represents economical target, especially in networks containing mixture of electromechanical and adaptive digital relays. The scheme decides the possible minimum number of re-adjusted relays and their locations in an optimum manner to achieve proper relays coordination in case of adding DGs. The proposed approach is divided into two successive phases; the first phase is stopped when the first relays coordination solution is achieved. The second phase increases the possibility to keep higher number of relays at their original settings than that obtained in first phase through achieving multi solutions of relays coordination. The proposed approach is implemented and effectively tested on the well-known IEEE-39 bus test system.

Ibrahim, D. K., E. E. D. A. El Zahab, and S. A. E. A. Mostafa, "New coordination approach to minimize the number of re-adjusted relays when adding DGs in interconnected power systems with a minimum value of fault current limiter", International Journal of Electrical Power & Energy Systems, vol. 85: Elsevier, pp. 32-41, 2017. AbstractWebsite

The presence of DGs in power networks tends to negatively affect relays coordination. Adding fault current limiters FCLs is one of the possible solutions to mitigate negative impacts of DGs addition on protection systems. Traditional schemes have estimated the minimum value of FCL to restore relays coordination when adding DGs without resetting of any relays. That minimum value of FCL in such case is called a critical value, where below this value the relays coordination will be lost.
Nowadays, designing FCL to simultaneously achieve two conflicted objectives of good performance and low cost is considered a great challenge. The paper introduces a new scheme to determine to what extent we could decrease FCL impedance value below its critical value with re-adjusting the original settings of only one adaptive relay to get relays coordination. Decreasing FCL value below its critical value will reduce the cost especially for superconductivity FCL. The proposed scheme can determine the location of that selected relay to be an adaptive one and estimate its re-adjusted new settings to be applied when DGs are added while inserting the reduced value of FCL.
Actually the proposed scheme can be applied for any networks irrespective of the number of added DGs and their capacities; while having an adaptive relay is the only requirement to implement it. The proposed approach is implemented and effectively tested on the large well-known interconnected IEEE-39 bus test system with 84 relays. Its results are compared with other approaches where, no readjusted relays settings are applied. A noteworthy advantage of the proposed scheme is the ability to implement a reduced FCL value than the critical value, by adjusting only one relay settings in the whole network. The proposed scheme may also be extended to re-adjust settings of more than one relay and get further reduced value of FCL. Furthermore, it is also shown that a more optimum value of the total operating time of all primary relays for near end faults is achieved when applying the proposed method rather than other traditional schemes.

Ibrahim, D. K., and M. E. Rezk, "A New Frequency Domain Filter for Precise Phasor Computation of Electrical Power Current", Journal of Electrical Engineering, JEE, vol. 18, issue Edition 2, pp. 73-80, 2018. Abstract

Digital filters of electrical protective relays play primary roles in calculating the fundamental phasors of electrical power signals. In most fault cases, large amounts of decaying DC components are included in the current signals during the fault period. Decaying DC component significantly reduces the precision and convergence speed of all conventional frequency-domain filters such as Fourier and Walsh filters. In this investigation, this paper introduces a new frequency-domain filtering algorithm to remove the decaying DC components and accurately capture the fundamental power system phasors for digital protective relays. This is executed by means of a mathematical procedure using digital signal processing techniques. The proposed filter is tested for a wide variety of current signals during different fault conditions to assess its performance. The simulation results show that the proposed filtering algorithm has a superior performance at a wide range of decaying components.

Gabr, M. A., D. K. Ibrahim, E. S. Ahmed, and M. I. Gilany, "A new impedance-based fault location scheme for overhead unbalanced radial distribution networks", Electric Power Systems Research, vol. 142: Elsevier, pp. 153-162, 2017. AbstractWebsite

This paper proposes an analytical impedance-based fault location scheme for distribution systems. The approach is based on voltage and current measurements extracted at only one-end feeding substation.Modal transformation is implemented to decompose the coupled three phase equations due to mutual effects into decoupled ones, and hence directly calculating fault distance in each section without iterative processes. The proposed approach considers various aspects of distribution systems: intermediate loads along the feeder, tapped laterals and sub-laterals at various nodes, time varying loads, and unbalanced operations. The proposed algorithm is extensively investigated on a typical real 11 kV distribution system,South Delta electricity sector, Egypt using MATLAB environment. Different cases are studied considering various loading conditions, varied fault resistance values and different fault types. The achieved results ensure the effectiveness of the proposed fault locator irrespective to fault conditions. Besides, the robustness of the proposed scheme against unbalanced loading, network topology change and non homogeneous network sections is also confirmed.

Saleh, S. M., and D. K. Ibrahim, "Non-Linear HIF Detection and Classification for Egyptian 500 kV Transmission Line", 14th International Middle East Power Systems Conference (MEPCON’10), Cairo University, Egypt, 2010. Abstract

High impedance faults (HIFs) are difficult to be detected or classified by overcurrent or distance relays. This paper presents a scheme for high impedance fault detection and classification in extra high voltage transmission line. The scheme recognizes the distortion of the current waveforms caused by the arcs usually associated with HIF using a discrete wavelet transform (DWT) based pattern recognition. The scheme uses a recursive method to sum the absolute values of the high frequency signal generated of line current signals measured at one substation end over one cycle. Proposed detector and classifier are tested under a variety of fault conditions on Egyptian 500 kV transmission line system by extensive simulation studies using HIF model of distribution system that modified to transmission lines. In addition, a real time HIF data recorded is used to validate the performance of the proposed scheme. All achieved results clearly reveal that the proposed scheme can accurately detect and classify HIFs in the transmission lines unaffected by fault type, fault inception angle, fault resistance, and fault location.

Shafei, M. A. R., D. K. Ibrahim, A. M. Ali, M. A. A. Younes, and E. E. L. - D. A. EL-Zahab, "Novel approach for hydrokinetic turbine applications", Energy for Sustainable Development, vol. 27: Elsevier, pp. 120–126, 2015. AbstractWebsite

By 2017, Egypt is expected to finish its sixth hydropower plant which is associated with the new Assiut barrage. Based on any hydraulic structure's design, there is enormous kinetic energy created downstream of the gates. This super power water jet generated under dams/barrage gates creates a destructive scouring effect downstream of the gates. In this work, a novel approach for hydrokinetic energy application is presented. The new approach proposes installing a farm of hydrokinetic turbines on the stilling basin of the spillways of the barrage's gate. This approach does not only magnify the total electric energy which was untapped in the past but also dissipates the enormous kinetic energy downstream of the gates. The total expected captured electric power from the barrage reaches 14.88 MW compared to 32 MW rated value of the existing hydropower plant.

Ismail, M., M. H. Alham, and D. K. Ibrahim, "A novel approach for optimal hybrid energy decarbonization using multi-criteria decision analysis: Abu Rudeis, Egypt as a case study", Energy Conversion and Management, vol. 290, issue 15 August , pp. Article no. 117199, 2023. AbstractWebsite

Converting from a complete fossil fuel energy system to a decarbonized one is crucial to mitigating climate
change and protecting human health. Hybrid energy sources are better than producing energy from a single
technology. The combination of renewable energy and fuel generators allows users to cover seasonal fluctuations of resources and protects them from the unpredictability of fuel prices and supply. Nonetheless, the large-scale industrial demand presents a real challenge due to its consistency throughout the day and the intermittent nature of renewable sources. This research proposes a novel approach for optimal hybrid energy decarbonization for any demand type in general and industrial demand in particular. The proposed framework is developed by integrating the Hybrid Optimization of Multiple Energy Resources (HOMER) for the simulations of Hybrid Configurations (HCs), the Electrical Transient Analysis Program (ETAP) for the stability studies, and the Potentially All Pairwise RanKings of all possible Alternatives (PAPRIKA) method to rank the resulting configurations.
An industrial oil and gas complex with high wind and solar resource availability is adopted as a study case. It is
located in Abu Rudeis, Egypt, and currently utilizes only 11 Gas Turbine Generators (GTGs) to generate electricity. Five different HCs are investigated, including PV and wind systems. The proposed approach considers technical, environmental, economic, and socio-political criteria, with a total of 21 sub-criteria, and reveals that incorporating a wind farm of nine 2-MW wind turbines with the GTGs is the Optimal Hybrid Configuration (OHC).

Khalil, E., T. A. Boghdady, M. H. Alham, and D. K. Ibrahim, "A novel cascade-loop controller for load frequency control of isolated microgrid via dandelion optimizer", Ain Shams Engineering Journal, vol. 15, issue 3, pp. Article no. 102526, 2024. AbstractWebsite

In fast-growing isolated microgrids (IMGs), load frequency control (LFC) ensures optimal power quality for end
users. Stochastic grids, notably with renewable energy resources (RESs), require robust and intelligently designed LFC schemes. Thus, this research presents a novel cascade-loop controller combining a fractional order proportional derivative with a filter and a fractional order-proportional tilt integral derivative (FPDN-FPTID)
to improve LFC for single and multi-area IMGs. Recent dandelion optimization adjusts FPDN-FPTID controller
settings. Anti-windup keeps the controller out of the non-linear zone for low inertia IMGs. It concerns various
sources’ maximum generating rates. The two-area IMG model shows its potential and scalability. Extensive
MATLAB/Simulink simulations show that the FPDN-FPTID controller outperforms numerous published controllers, either single or cascade-loop, in minimum error criteria, undershoots/ overshoots/settling times, frequency, and tie-line power deviation following load and RES variations. Finally, the sensitivity study indicates
the suggested controller stabilizes the system despite ±25 % parameter changes.

Khalil, E., T. A. Boghdady, M. H. Alham, and D. K. Ibrahim, "A novel multi-objective tuning formula for load frequency controllers in an isolated low-inertia microgrid incorporating PV/wind/FC/BESS", Journal of Energy Storage, vol. 82, issue 30 March 2024, pp. Article no. 110606, 2024. AbstractWebsite

Load frequency control (LFC) is vital for isolated microgrids (IMGs), especially when uncertain renewable energy sources (RESs) are present. Enhancing LFC schemes relies mainly on three tracks. Adding new resources to IMG structures is the first track, designing novel controller structures for LFC schemes is the second, and the third is improving controller tuning procedures in the LFC schemes. This research suggests an innovative multi-objective formula (MOF) for controller tuning that combines a novel error criterion termed the integral-square time absolute error of frequency change with the integral-square of IMG controllers' signals. Tested IMG includes multi-sources of diesel engine generators, fuel cells, battery energy storage technologies, and RESs (like photovoltaic and wind turbines). The proposed MOF tuning is evaluated compared to four different objective functions, which are the integral-absolute error (IAE), integral-time absolute error (ITAE), integral-square error (ISE), and integral-time square error (ITSE). The proportional-integral-derivative (PID), fractional-order, and cascade PID controllers are implemented to appraise the proposed MOF extensively against all these single objectives. Statistical analyses are accomplished comprehensively to verify the effectiveness of the artificial rabbits' optimization algorithm (ARO) in competition with other recent optimization algorithms to tune different controllers utilized in the LFC schemes of the examined IMG based on tested objectives. Therefore, ARO is applied to optimize controller settings by combining system nonlinearities with IMG sources' maximal generation rate constraints. The comparative analysis considers settling times, overshoots, IAE, ITAE, ISE, and ITSE performance indices. MATLAB/Simulink simulations confirmed the ability of the suggested MOF tuning to stabilize the system and keep improving performance indices, significantly attaining the minimum settling time even for massive three-type load fluctuations. The first type is step disturbances ranging between 0.1 and 0.25 p.u, the second is varying step disturbances every 5 s, and the third is severe dynamic random load shifts from −0.2 to 0.2 p.u. In addition, the MOF outperforms other competitors' tuning formulas while adding fluctuations of RESs with load disturbances. Furthermore, the robustness analysis is conducted for the applied controllers based on the proposed MOF tuning approach by changing the IMG nominal parameters with ±25 % and adding system nonlinearities. The analysis ensured its efficacy in preserving system stability. Finally, the stability test in the frequency domain using the MATLAB/control design tool verified system stability when different LFC controllers were tuned based on the proposed MOF tuning.

Hamza El-Sayed, K., D. K. Ibrahim, and E. E. - D. A. El-Zahab, "Operation and Control of 850kW Doubly Fed Induction Generators Based Al-Zafarana Egyptian Wind Farm", International Journal of Electrical Energy, vol. 4, issue 2, pp. 112-121, 2016. AbstractWebsite

With increasing global great concern over greenhouse gas emissions and their harmful effects on environment, huge number of wind turbines are recently connected to electrical grids. Nowadays, Egypt has continuous development of wind energy projects; it makes a great effort at Gulf of Suez area especially in Al Zafarana district. This paper focuses on studying the dynamic performance of the 5th phase of Al-Zafarana wind farm, which is made of 100 Gamesa G52/ 850kW Doubly Fed Induction Generator (DFIG) machines, using Digsilent /PowerFactory simulation tool as an advanced simulation package. As DFIG is currently one of the most common types employed for Wind Energy Conversion System (WECS), the paper also implements a dynamic model for 850 kW DFIG machine based WECS in Matlab / Simulink environment. A dual reference frame control strategy is applied here to improve the dynamic system performance during balanced and unbalanced grid voltage conditions.

Fayoud, A. B., H. M. Sharaf, and D. K. Ibrahim, "Optimal coordination of DOCRs in interconnected networks using shifted user-defined two-level characteristics", International Journal of Electrical Power and Energy Systems, vol. 142, issue Part A, pp. Article no. 108298, 2022. Abstract

This paper introduces a protection scheme for interconnected networks based on proposed Directional Overcurrent Relays (DOCRs) with user-defined two-level characteristics. By getting usage of the capabilities available in modern digital DOCRs, the proposed relay will have two user-defined characteristics; one for its primary operation and another for its backup operation (two-level characteristics) to fit a specific application or system. The coordination between the proposed relays is formulated and solved as a non-linear optimization problem to minimize their operating time and reduce the thermal impact caused by short circuit currents through electrical equipment while maintaining the technical constraints.
Extensive comparative studies have been performed to ensure the effectiveness of the proposed protection
scheme. Firstly, the performance of the traditional one-level characteristic relay (COLC) with two settings is
compared to the conventional two-level characteristic relay (CTLC) with three settings. Then a further investigation is carried out by suggesting increasing the number of settings to seven, named as the user-defined two-level characteristic relay (UDTLC), and then to nine settings, named as the shifted-user-defined two-level characteristic relay (SUDTLC). Finally, different multi-objective functions with proper weighting factors are investigated to determine the most effective one with the best performance for the proposed idea.
The distribution portion of the IEEE 30-bus system has been used to test and verify the proposed characteristics extensively. The optimal coordination problem is solved using the fmincon function in MATLAB. Based on the achieved results, the proposed characteristics of UDTLC and SUDTLC guaranteed a considerable reduction in operating times. In addition, the achieved results deduced that using a different multi-objective formulation has little impact on reducing operating time due to using the proposed characteristics UDTLC and SUDTLC, which means solving the coordination problem is mainly dependent on the applied characteristics.