Doaa Khalil Ibrahim

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.

A comprehensive two-terminal impedance based fault location scheme is presented in this paper which takes into account the distributed parameter line model. The scheme utilizes unsynchronized measurements of voltages and currents from the two ends of a line. The synchronization angle is calculated using symmetrical components transformation theory. The proposed scheme integrates several fault location algorithms. In one of them, Takagi method is used taking into account the effect of distributed capacitance when the communication link between sending end and receiving end fails.
Another algorithm is embedded in the proposed scheme to accurately locate ground and phase nonlinear high impedance faults using zero and negative sequence currents gathered from the two terminals within a maximum time of 2 cycles. The proposed fault-location scheme has been thoroughly tested using ATP versatile simulations of faults on transmission lines. The presented evaluation shows the validity of the developed fault-location scheme and its accepted accuracy.

Coordination between inverse time overcurrent relays within meshed systems are achieved by adjusting two relay settings; pick up current and time multiplier settings. The operating time of these relays is also a function of two additional constants; one represents the constant for relay characteristics and the other one represents the inverse time type. For typical relays, each of these two constants has four definite values and choosing between them indicates the selected relay operating curve: either standard inverse, very inverse, extremely inverse or long time standby earth fault time-current relay characteristics. In this paper, a coordination strategy, that takes advantage of the available capabilities in microprocessor based relays, is proposed by considering the two relay characteristic constants as continuous variable settings that can be adjusted in addition to the conventional pickup current and Time Dial Setting (TDS). The protection coordination problem is formulated as a nonlinear programming problem where the main objective is to minimize the overall time of operation of relays taking into account protection coordination constraints. The proposed approach is applied to the IEEE 14 bus system and is compared with the conventional two setting relay.

FCL (fault current limiter) is used to solve relays miscoordination problem arises from DG (distributed generation) installation. In most published researches, different optimization methods are developed to obtain optimal relay settings to achieve coordination in case of not installing DG, then depending on the achieved optimal obtained relay settings, FCL impedance is deduced to ensure relays coordination restoration in case of installing DG. Based on original optimal relay settings, obtained FCL impedance is not the minimum one required to achieve relay coordination. The contribution of this paper is the generation of multi sets of original relay settings that increase the possibility of finding FCL impedance of minimum value which is lower than the calculated value based on original optimal relay settings. The proposed method achieves better economic target by reducing FCL impedance. The proposed approach is implemented and tested on IEEE-39 bus test system.

Dynamic Voltage Restorer (DVR) is a fast, flexible and efficient solution for voltage sag problem. It is a power electronic based device that used to compensate voltage sags and harmonics. The DVR has different system topologies for compensation by using battery as an energy storage unit or by using shunt and series converters. In this paper, the DC-DC boost converter is used to connect between shunt and series converters, which allows the DVR to compensate deep sags for long durations. A real case study of Egyptian industrial plant includes a lamp factory as a sensitive load is modeled and simulated using MATLAB/SIMULINK environment to test the effectiveness of using different system topologies of DVR: a battery, shunt and series converters, and finally shunt and series converters with boost converter. Satisfactory performance is achieved using the topology of using shunt and series converters with boost converter for compensating deep voltage sags and harmonics. The financial assessment of using DVR is also investigated.

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.

To ensure high reliability of the power system, distance relays are blocked during power swings. However, if a fault occurs during a power swing, it should be detected and the unblocking function should be invoked to clear the fault as soon as possible. Distinguishing stable and unstable power swing is one of the challenging tasks for distance relays. This paper proposes a combined scheme for detectingfaults occurrence during power swings and accurate determination of power swing stability status. The proposed scheme utilizes a differential power-based technique and a negative sequence current based technique for detecting faults occurrence during power swings. Moreover a wavelet based power angle criteria based algorithm is applied for distinguishing stable and unstable power swings. The proposed scheme is extensively tested for symmetrical and unsymmetrical faults during slow and fast power swings for simulated tested power systems using ATP software.

This paper presents a new adaptive tripping time scheme which provides high speed distance relay operation under fault conditions near the relay point and provides high secured detection for the faults occurred at the end of the protected transmission line with tripping time less than one power cycle. The proposed scheme automatically controls the data window length to adaptively speed up its response under various fault conditions. The advanced feature of this scheme provides capability for fast tripping decisions with secure operation. The proposed scheme possesses the advantage of removing decaying DC offset component in the current signals according to the length of data window, and compensates the capacitive current during the calculation of the fault impedance. Extensive simulations show that the proposed scheme provides better protection performance compared with the conventional schemes of the fixed data window.

This paper presents a comparative study between different configurations of photovoltaic (PV) systems which are the stand-alone (PV) system, the PV-diesel- battery hybrid system and the grid connected PV system. The main objective is to select the optimal system configuration for supplying the electrical load of an Egyptian isolated village. Design calculations are carried out using three different techniques which are: Heuristic approach, loss of power supply probability indices, and HOMER software analysis. The life cycle cost (LCC) analysis is also conducted to assess the economic viability of designed system. As for determining the optimal PV panels tilt angle, three cases are studied. The paper also shows the effect of electricity price on PV standalone system, and grid extension.

Directional inverse time overcurrent relays are used in protection systems of meshed networks to operate for fault currents in its forward zone of operation. They are used for primary and backup protection and their operation needs to be coordinated to assure selectivity. Different optimization techniques have been used to select their settings to achieve protection coordination, however the optimal protection coordination problem formulation doesn’t consider the fault current direction to assure correct operation especially for
backup relays. This paper proposes the addition of fault current direction constraint to the formulation of the optimal directional inverse overcurrent relays coordination. The proposed formulation is tested on the distribution portion of the IEEE 30 bus system considering the effect of distributed generation addition. Results show that the proposed formulation gives more accurate optimal relay settings and thus highlighting the importance of inclusion of the proposed direction constraint in the protection coordination problem.

For the development of energy sources in rural regions in Egypt at the brink of the 21st century, it may be necessary to use solar energy in all applications as one of the most promising new, clean and renewable energy sources. This paper presents a study for a stand-alone photovoltaic (PV) system design to provide the required electricity for an isolated village in Mersa Matrouh, Egypt. The complete design of the suggested system is achieved by optimization techniques using different software. In addition to taking into account site radiation data and electrical load data of this typical village, the life cycle cost (LCC) analysis is also conducted to assess the economic viability of the designed system.

Over the last few decades, like many other countries around the world, Egypt is facing the challenge of the need to expand higher education enrolment, both for meeting the growing demand and also the realization of the importance of higher education in nation economic development. Since year 2000, Egypt worked on improving higher education through developing and implementing a comprehensive strategic plan adopting the principles of equity, quality and relevance, and responding to the current and future needs of social development, job market and production as one of the main goals. The establishment of the National Authority for Quality Assurance and Accreditation in Education (NAQAAE) in 2006 as an independent authority did set national quality standards to be met by higher education institutions for accreditation. The Program of Continuous Improvement and Qualifying for Accreditation (PCIQA) was initiated in 2007 by the Ministry of Higher Education for financing, through a competitive mechanism, and technically supporting higher education institutions to implement their strategic plans, fulfil accreditation quality criteria and assure continuous improvement. This paper reviews the Egyptian experience in providing mass higher education and assuring its quality, highlighting the innovative approaches adopted both on the national strategic policies and the individual institutions practice levels.

This paper presents a scheme to increase the sensitivity of overcurrent protection. The proposed scheme applies wavelet packet transform, since it can preserve both time and frequency information with high resolution. The proposed scheme demonstrates its feasible performance in detecting short circuit faults, calculating fault location with moderate accuracy and detecting nonlinear high impedance faults. In addition, the proposed scheme examines the load current continuously and has the ability of changing the relay pick up value adaptively. The examined tested cases include different internal short circuit fault conditions, different nonlinear high impedance faults, and non fault situations such as normal load changing. The obtained results indicate that the developed scheme is fast, robust, reliable and suitable for power distribution systems.

Series compensated lines present challenges for directional, distance, and differential elements because the transient response of the series capacitor is not readily predictable. This paper presents a directional overcurrent relay that used as a backup protection for distance relays in series compensated lines. Wavelet Packet Transform (WPT) technique is used for proper fundamental RMS value calculating of current and voltage signals since it can preserve both time and frequency information with high resolution by decomposing a waveform into uniform frequency bands, and measuring individual harmonic components. The proposed scheme demonstrates its feasible performance in detecting nonlinear high impedance faults with low voltage and current variation for maximum trip time required of 2 cycles. In addition, the proposed scheme examines the load current continuously and changes the relay pick up value adaptively. Characteristics of the proposed scheme are fully analyzed by extensive ATP/EMTP simulation studies that clearly reveal that the proposed scheme has an efficient performance insensitive of the variation of different fault conditions that may occur in double ended transmission lines with series capacitors at the middle of the line.

This paper addresses the optimal allocation of Flexible AC Transmission Systems (FACTS) devices in a power system in order to improve voltage stability. With the continuous increase of power demand, FACTS provide a suitable solution by maximizing the usage of existing utilities rather than increasing power generation and building new lines. Due to high cost of such devices their optimal allocation must be ascertained. Particle swarm optimization (PSO) is used in this paper to determine the best location and size of Static VAR Compensator (SVC) where the objective function is to achieve the accepted voltage profile taking into consideration the SVC cost. Simulations are performed on IEEE-14 test system. Results prove the effectiveness of PSO in solving such allocation problem.

The aim of this paper is to determine the possibility of using a stand-alone hybrid energy system to meet the electric load demand of an isolated area using HOMER Software. The combination of using remote area-diesel generators and renewable energy source such as photovoltaic system (PV) with a battery storage can greatly overcome some of diesel generators problems. In this paper, a PV/Diesel generator hybrid energy system is sized to meet the load with about 100 % availability. HOMER is used to optimize the operation of the diesel generator and to calculate the optimum number of the PV modules and batteries that would achieve the minimum initial cost and a desired depth of discharge for battery storage. As the economic issue is greatly concerned, it is necessary to identify the system life cycle cost or the Total Net Present Cost, TNPC, of the optimal hybrid energy system which can also be achieved by HOMER optimization. For observing the economic and technical feasibility of the designed power system and its economics, it is important to assess the effect of uncertainty or the change of several variables such as solar radiation, interest rate and fuel price which can be carried out by performing several sensitivity analyses.

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).

Connection of distributed generation (DGs) powered by renewable energy resources in power systems has numerous benefits. However the presence of these (DGs) increase the fault current levels in different points, and disturb the protection coordination of the existing relays. Two approaches are proposed for coordination of directional overcurrent relays (DOCRs) in power systems with (DGs), depending on the types of system relays either adaptive or non adaptive. For adaptive protection system, the first proposed approach is based on linear programming technique which used to calculate the relay settings in case of DGs existing or not. For non-adaptive protection system, the second proposed approach is introduced, in which minimum impedance of fault current limiter is calculated to restore the coordination of relays without altering the original relay settings. The two proposed approaches are implemented and tested on IEEE-39 bus test system.

Internal and external measures assuring quality in Egyptian higher education institutions and the improvement in higher education as a result are discussed in this study. Effect of QA processes on internal mechanisms and the role of such QA processes in policy making at both the institutional and national levels are also investigated with reference to some case studies. Internal mechanisms are implemented through QA units in colleges/institutes, QA centers in universities, and projects for QA and qualifying for accreditation financed by the "Ministry of Higher Education". These projects are managed by a "Steering Committee for The Program of Continuous Improvement and Qualifying for Accreditation". The need for continuous improvement urged faculties to adopt certain policies to deal with points of weakness where some faculties intended to have a formal system to deal with student complaints, to handle resistance to change among faculty staff and administrative personnel, and to think of strategies for dealing with the bureaucracy. The needs of higher education systems in Egypt for external and internal QA measures are evident and therefore, several proposals for ensuring sustainability are suggested. "The National Authority for QA and Accreditation of Education" plays a pivotal role in external evaluation of QA activities in higher education institutions. Its basic principles are inspired from the good systems and practices aimed to assure quality of education. Cooperation of Egyptian higher education institutions with QA agencies are also discussed in this paper while referring to means of identification and dissemination of good practice for the purpose of continuous improvement.

This article presents a central relay based on wavelet transform for high- impedance earth fault detection, zone identification, location, and classification in part of the Egyptian 500-kV transmission network. The scheme recognizes the distortion of the voltage and current waveforms caused by the arcs usually associated with high-impedance earth faults for unsymmetrical faults, whether single line to ground fault or double line to ground fault. The proposed discrete wavelet transform based analysis yields three phase voltages in the high-frequency range and zero-sequence root mean square current in the low-frequency range that are fed to fault detection and location algorithms, respectively, while phase currents in the high frequency range are fed to the classification algorithm. The fault detection algorithm is based on the recursive method to sum the absolute values of the high-frequency signal generated over one voltage cycle, while the zone identification and fault location algorithms use unsynchronized zero-sequence root mean square currents.On the other hand, the fault classification algorithm is based on the currents in the high frequency range for one- side data of the faulted line at the local relay after the detection and location process. Characteristics of the proposed central relay are analyzed by extensive simulation studies that clearly reveal that the proposed relay can accurately determine the network faulted line and can calculate fault distance with an acceptable error that does not exceed 5%. All simulation studies are carried out using a high-impedance earth fault model of a distribution system that is modified for transmission systems. An available real high-impedance earth fault case study is used to check the performance of the fault classification algorithm to classify phase and earth faults.

Nuclear Power Reactors (NPRs) are large in scale and complex, so the information from local fields is excessive, and therefore plant operators cannot properly process it. When a plant malfunction occurs, a great data influx is occurred, so the cause of the malfunction cannot be easily or promptly identified.
A typical NPR may have around 2,000 alarms in the Main Control Room (MCR) in addition to the display of analog data. During plant transients, hundreds of alarms may be activated in a short time. Hence, to increase the plant safety, this paper proposes a support system based on neurofuzzy that assists alarming and diagnosis systems. Throughout this framework the neurofuzzy fault diagnosis system is employed to fault diagnosis of nuclear reactors. To overcome weak points of both linguistic and neuro learning based approaches, integration between the neural networks and fuzzy logic has been applied by which the
integrated system will inherit the strengths of both approaches.

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.

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.