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Zeinhom, A. N., D. K. Ibrahim, and M. Gilany, "Integrated Fault Zone Discrimination and Fault Location Algorithm for Series FACTS-based Transmission Lines", 2018 Saudi Arabia Smart Grid (SASG), Jeddah, Saudi Arabia, 11-13 Dec. 2018. Abstract

Discrimination and location of faults in Flexible Alternating Current Transmission Systems (FACTS) have several challenges in power systems. This is because of the errors in the measured impedance due to FACTS control actions. The presence of series FACTS in a transmission line complicates both the fault location and discrimination between faults behind and in front of the FACTS device. This paper proposes an integrated solution for both fault zone discrimination (either in front of or behind the FACTS device) and fault location for series FACTS-compensated transmission lines. Online calculations are carried out to estimate the percentage of compensation. After fault inception, a wavelet-based algorithm is used to decide whether the fault is in front of the FACTS device or behind it. Then, a conventional distance protection algorithm is used to estimate the fault zone. After that, synchronized data signals from both ends are used to locate the exact location offline. The algorithm is tested using a real data for a 380 kV, 400 km series-compensated line in Saudi Arabia using MATLAB/SIMULINK. Different types of faults are applied to validate the effectiveness of the algorithm. Metal-Oxide Varistor (MOV) nonlinearity is also considered. Simulation results show the effectiveness of the algorithm.

Zeineldin, H. H., H. M. Sharaf, D. K. Ibrahim, and E. E. - D. AbouEl-Zahab, "Optimal Protection Coordination for Meshed Distribution Systems With DG Using Dual Setting Directional Over-Current Relays", IEEE Transactions on Smart Grid, vol. 6, no. 1: IEEE, pp. 115–123, 2015. AbstractWebsite

In the presence of distributed generation (DG), it is important to assure a fast and reliable protection system for the distribution network to avoid unintentional DG disconnection during fault conditions. In this paper, dual setting directional over-current relays are proposed for protecting meshed distribution systems with DG. Dual setting relays are equipped with two inverse time-current characteristics whose settings will depend on the fault direction. The protection coordination problem for the dual setting directional relay is formulated as a nonlinear programming problem where the objective is to minimize the overall
time of operation of relays during primary and backup operation.
The proposed protection coordination scheme using dual setting relays is compared against the conventional approach, which relies on the conventional one setting directional relay. The proposed scheme is applied to the power distribution network of the IEEE 30-bus system equipped with synchronous and inverter-based DG. The results show that the proposed protection coordination scheme with dual setting relay can significantly reduce the overall relay operating time, making it an attractive option for distribution systems with DG.

Yousef, W. H., D. K. Ibrahim, and E. Abo El-Zahab, "Discrimination of Internal Faults and Inrush Currents For Large Modern Power Transformer", 14th International Middle East Power Systems Conference (MEPCON’10), Cairo University, Egypt, 2010. Abstract

This paper presents a differential protection approach for large high quality power transformers that have
low inrush currents of about 3.14 times rated currents. Such transformers have low second harmonic level, which results in conventional differential protection malfunction. A scheme for internal faults and inrush currents discrimination based on both discrete Fourier transform DFT and discrete Wavelet Transform
DWT is proposed. The proposed method has been designed based on the percentage of the sum of wavelet transform coefficients D1 and fundamental differential current (based on a 1 kHz sampling
rate). It has been tested by extensive EMTP/ ATP simulations for different faults and switching conditions on El Tebbin Power Plant 220/21 kV generator/power transformer. It is proved that it has a high capability for discrimination even in the case of inrush with low second harmonic content and internal fault currents with high second harmonic component. All tests proved that the proposed scheme is reliable, accurate, and fast.

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.

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.

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.

Soliman, A. A. R. A. A., M. M. Sayed, and D. K. Ibrahim, "Optimized hybrid microgrid of gas generators-wind farm using crow search algorithm", Proceedings of the 2017 Saudi Arabia Smart Grid (SASG), 12-14 Dec. 2017, Jeddah, Saudi Arabia, 2017. Abstract
Shazly, J. H., M. A. Mostafa, D. K. Ibrahim, and E. A. E. E. Zahab, "Thermal Analysis of HV Cables with Several Types of Insulation for Different Configurations in The Presence of Harmonics", IET Generation, Transmission & Distribution, vol. 11, issue 14, pp. 3439 –3448, 2017. AbstractWebsite

In this contribution, the three-phase underground cable is modelled using COMSOL Multiphysics software to evaluate the steady state and transient thermal performances. Finite element technique is applied using the heat conduction equation to study the temperature distributions in power cables components and the surrounding environment for both linear and non-linear loads. A real case study of 220 kV, 340 MVA three phase single core copper cables insulated by XLPE is studied. Other types of insulation such as oil, and SF6 gas and their contributions of convection and radiation are investigated at trefoil and flat configurations. The loading capability under different ambient conditions for average moisture soil and dry soil with low moisture content are also evaluated taking into account the unfavourable effect of dry zones formation. Moreover, the challenge of predicting the accurate thermal performance and estimating the required derating factor in the presence of odd harmonics is considered. The effect of the change of the frequency spectrum of the non-linear load current by involving different simultaneous harmonic orders for the same total harmonic distortion is extensively investigated for both flat and trefoil configurations. It is concluded that all harmonics contributions should be considered, to accurately calculate the required cable derating.

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.

Shafei, M. A. R., D. K. Ibrahim, A. El-Zahab, E. El-Din, and M. A. A. Younes, "Biogeography-Based Optimization Technique for maximum power tracking of hydrokinetic turbines", Renewable Energy Research and Application (ICRERA), 2014 International Conference on: IEEE, pp. 789–794, 2014. Abstract

Hydrokinetic energy, referring to the energy contained in moving water, is a renewable energy source that gained much consideration in the past years and expected to play a significant role in the future. The energy is initiated in all moving water masses, but is significantly economic to convert for water masses moving with high velocity. Nonlinear characteristics of water speed and generator model in hydrokinetic energy conversion systems require an optimal controller for achieving optimal performance and high efficiency of the system. Here, the field oriented control method is proposed to set the PI controllers which their coefficients are optimized based on Biogeography- Based Optimization technique (BBO). In order to use BBO to solve this problem, the problem has to be formulated as an optimization problem. Numerous simulation studies are carried out to verify the effectiveness of the proposed controller scheme. Achieved results for different patterns of water speed changes in time domain show the capability of the proposed control.

Shafei, M. A. R., D. K. Ibrahim, and M. Bahaa, "Application of PSO tuned fuzzy logic controller for LFC of two-area power system with redox flow battery and PV solar park", Ain Shams Engineering Journal, vol. 13, issue 5, pp. Article No. 101710, 2022. Abstract

Nowadays, integrating large scale renewable energy sources, like solar PV parks, raises challenges for Load Frequency Controllers (LFC). The output of PV varies continuously, which requires a robust LFC deals
logically without continuous tuning and parameters optimization. In this paper, a fuzzy logic controller (FLC) is proposed to act as the main LFC instead of the traditional proportional–integral–derivative (PID) controller. The dynamic performance of FLC is enhanced by optimizing its parameters for different cost functions using particle swarm optimization technique (PSO). Another two FLCs will be added to PV system to act as an output controller instead of maximum power point tracker (MPPT) to enhance the overall system performance. To increase system reliability, a fast active power source called redox flow battery (RFB) is added in the proposed model as a frequency stabilizer. RFB can deeply discharge up to 90% with theoretically limitless number of duty cycles and has fast time response for severe load changes. The
importance of these proposed controllers side by side with RFB is to avoid disconnecting solar parks during
heavy cloudy days while preserving on maximizing its output during these periods. The superiority of the proposed FLC is examined by evaluating its performance compared to another control approach called PID-P (PID controller with P controller in the inner feedback loop). Finally, a comprehensive sensitivity analysis is also presented to investigate the controller robustness for extensive changes in power system parameters and loading.

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., D. K. Ibrahim, and E. E. - D. A. El-Zahab, "Transient stability enhancement of Egyptian national grid including nuclear power plant in Dabaa area", Power and Energy (PECon), 2012 IEEE International Conference on, Kota Kinabalu Sabah, Malaysia, IEEE, pp. 487-492, 2012. Abstract

The main purpose of this paper is focused upon the enhancement of transient stability and improvement of the dynamic behavior of Egyptian electrical power grid including new nuclear power station in Dabaa area. This target is achieved via employing only one device as a first approach of solution. That device is the Static VAR Compensator (SVC). Capability of that device to provide synchronizing torque is tested at different implementation conditions, as well as, different locations of feedback signals. For that purpose, singular value decomposition is used and siting index program is created. A second approach of solution is also proposed, in which a Power System Stabilizer (PSS) is added as a more effective device in providing damping torque. For the two proposed approaches, devices' time constants and gains are set using genetic algorithm optimization technique (GA).

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., M. S. Mohamed, A. A. Mansour, and D. K. Ibrahim, "Recharging Portable Devices by Photovoltaic Modules Using Inductive Power Transfer", International Journal on Energy Conversion (IRECON), vol. 9, issue 5, pp. 230-238, 2021. Abstract

Portable devices are part of people’s daily lives, since they provide the capabilities that make life easier. However, they consume much energy that requires continuous charging. Integrating renewable energy sources, especially photovoltaic (PV) modules into wireless charging, has been widely adopted in order to increase availability, flexibility, safety, and robustness. In this paper, a new variable frequency control technique for inductive power transfer (IPT) is proposed in order to overcome the switching frequency limitation and increase the transfer efficiency without increasing the switching frequency. At first, charging power (PV power) is stored in a battery. Then, it is transferred based on inductive coupling when needed. The hardware of the proposed wireless charging system has been carried out for two different configurations. The first one is the single switch using a variable frequency control algorithm, which has achieved 40% efficiency. The other one uses half-wave inverter applying no resonance for two types of core: Nano-crystalline and ferrite. For that configuration, the maximum achieved efficiency has been 80% at zero air gap and 36.91% at the 5 mm air gap by the Nano-crystalline core.

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.

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.

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.

Saleh, S. M., and D. K. Ibrahim, "Non-linear high impedance earth faults locator for series compensated transmission lines", Power Systems Conference (MEPCON), 2017 Nineteenth International Middle East: IEEE, pp. 108-113, 2017. Abstract
Saleh, S. M., and D. K. Ibrahim, "Fault Detection Technique of High Impedance Faults in EHV Transmission Lines Using Combined Wavelet Transform and Prony’s Method", 16th International Middle East Power Systems Conference, MEPCON 2014, 2014. Abstract

High impedance faults (HIFs) are difficult to detect by conventional protection devices such as distance and
overcurrent relays. This paper presents a scheme for high impedance fault detection in extra high voltage transmission line by recognizing the distortion of the voltage waveforms caused by the arcs usually associated with HIFs. The proposed scheme is based on combined wavelet transform and Prony’s method. The discrete wavelet transform (DWT) based analysis, yields three phase voltages in the high
frequency range which are fed to a classifier for pattern recognition and also fed to the Prony’s method for correct discriminating of switching with and without fault cases. The classifier is based on an algorithm that uses a recursive method to sum the absolute values of the high frequency signal generated over one cycle by shifting one sample, while switching cases discrimination is based on Prony’s amplitude changing
with time. Characteristics of the proposed fault detection scheme are analysed by extensive simulation studies that clearly reveal that the proposed scheme can accurately detect HIFs in the EHV transmission lines. Results of extensive simulations using ATP/EMTP on 500 kV Egyptian transmission line clearly reveal that the proposed scheme can accurately detect HIFs in the EHV transmission lines systems as well as its ability to discriminate clearly between HIFs and various switching conditions.

Saleh, S. M., E. M. Aboul-Zahab, E. Tag Eldin, D. K. Ibrahim, and M. I. Gilany, "Neural network-based technique used for recovery the CCVT primary signal", Power & Energy Society General Meeting, 2009. PES'09. IEEE: IEEE, pp. 1-7, 2009. Abstract

The coupling capacitor voltage transformers transient response during faults can cause protective relay mal-operation or even prevent tripping. This paper presents the CCVT transient response errors and the use of artificial neural network (ANN) to correct the CCVT secondary waveform distortion. In this paper, an ANN program is developed to recover the primary voltage from the distorted secondary voltage. The ANN is trained to achieve the inverse transfer function of the coupling capacitor voltage transformer (CCVT), which provides a good estimate of the true primary voltage from the distorted secondary voltage. The neural network is developed and trained using MATLAB simulations. The accuracy of the simulation program is
confirmed by comparison of its response with that of the target value from the simulation data.

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.

Sabra, H., D. K. Ibrahim, and M. Gilany, "Unnecessary Simultaneous Trip in Distribution Networks", 17th International Middle East Power Systems Conference, MEPCON 2015; Mansoura University, Egypt, December, 15-17, 2015., 2015. Abstract

In medium voltage distribution network, the phenomena of having a simultaneous false trip on healthy feeder/feeders during a real fault on another feeder is common. It affects badly the continuity of service. In this paper, three different causes of this unnecessary simultaneous tripping in distribution networks are discussed. The earth fault element problems caused by these phenomena are also evaluated. A practical solution for this problem is proposed by using the custom logic scheme exists in the digital protection relay. The proposed method is applied to an actual system utilizing the existing protective digital relays. Actual records for faulty phase current and calculated zero sequence currents were captured and analyzed by means of digital fault recorders exist in the protection relay. The obtained results are encouraging and indicate the suitability and advantages of the proposed method.

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.

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.