المجلد 2 - العدد 1

يونيو 2020

محتويات الجزء العربي

رئيس التحرير

التصحر وطرق مكافحته

ناجية ابراهيم الغراري (كلية التربية ناصر جامعة الزاوية) najia.algrari@gmail.com

English Part-Contents

Editor-in-Chief

Modeling and Simulation of a Large-Scale Grid-Connected Wind-Turbine-PV-BatteryDiesel Hybrid Power System

This research aims to investigate and analyze PV generators, wind energy generators, and energy storage system for stabilizing and grid support functions. The analysis will proceed from both an economic and a technological perspective. More specifically, we will look at the blueprints for a 10 MW solar power facility in the eastern Canadian province of Prince Edward Island (PE). Our inYeVWigaWion Zill inclXde eVWimaWing Whe faciliW\¶V annual performance and formulating the performance ratio against various types disturbances. This model incorporates work that is already being done on wind turbines (WEICan) in PE, and the WEICan data is combined with the model to produce a 20 MW simulation using a BESS (battery energy storage system) to create a novel grid-connected photovoltaic wind turbine BESS diesel generator (or PV-WTBESS-DG) hybrid system that also includes controllers and converters. A perturb and observe (P&O) algorithm is employed to optimize the amount of energy produced according to the maximum power point tracker (MPPT) and the proposed model undergoes simulated tests for a variety of weather- and solar-dependent operating conditions

Osama Alagili (Faculty of Engineering and Applied Science, Memorial University of Newfoundland, St. John¶V NL, A1B 3X5 Canada.)

Comparison between a Mamdani and Sugeno Controllers Based Power Theft Detection

In this paper a proposed system is set to identify the illegal power theft on electrical grids by utilizing a wired control system based on microcontrollers. The proposed system allows easy access to the information with the combination of a traditional power grid and a new technology (Arduino kits). A novel automated control system was proposed in this paper, which makes use of Arduino based fuzzy logic Toolbox in MATLAB. Arduino has been used in the proposed system to monitor and record the meter readings while fuzzy logic controllers have been used to act as a relay. Simulations have been implemented through this work based on a fuzzy inference systems using Toolbox/ MATLAB. The paper shows a comparison between two inference types, namely, Mamdani-type and Sugeno-type. Although both of these two types are varying slightly in terms of their design's steps, results of the Sugeno-type inference system indicated that it is able to prevent any value of stealing electricity even less than Nano amperes comparing with another type due to its output membership functions are crisp. By using the Sugeno controller, the controller’s response is more accurate and better than the Mamdani controller's output. The results obtained from the simulation show that immediately the illegal load is connected to the utility system. Whereas, the results obtained from the hardware show that any unexpected usage is instantaneously being sent to the utility. This project is significantly useful to prevent instantly power theft when it has been discovered, consequently illegal users won’t be able to use.

Abdalla Fadel (Professor - School of Engineering and Applied Science/ Libyan Academy) fadel.abdalla@zu.edu.ly

Manal Shlibek (Engineer at GECOL- MSc- Electrical Engineering/ Libyan Academy) manal.shlibek@gmail.com

Taha Shlibek (Engineer at Huawei- MSc- Nanjing university of Aeronautics and Astronautics) Shlibektaha@gmail.com

Nada Fadel (Engineer at Faculty of Petroleum Engineering- Tripoli University) nada.fadel94@gmail.com

Computerized Data Acquisition System for Minimizing Electricity Theft

Electrical power theft is the main cause of Non-Technical Losses (NTL) in the power grids. To solve this problem, the authors suggest an Arduino based system with the assistance of other devices to automatically detect and control power theft. In this paper power consumption data is classified into the no-load, normal load, and theft load data. The proposed system is termed as “Computerized Data Acquisition System for Minimizing Electricity Theft” as it receives the consumption data from the consumer side and then classifies this data based on how it is to be handled for data acquisition, monitoring, and detection. In no-load condition, the source side does not receive any electrical signal from the consumer side, indicating no consumption for that particular household. In normal load conditions, the consumer side sends current consumption information to the source end, and the source shall then compare it with the measured line current. if data is similar, no power theft signal is generated. Otherwise, a probable theft (an illegal connection of electricity) took place. This paper introduces a data acquisition strategy that is based on Arduino to convert an analog sensor data to a digital signal to be fed to the Arduino for further handling. The obtained results after testing the system proved to be accurate and reliable. Energy consumption was timely monitored and displayed on an LCD screen. 

Taha Shlibek (Master student at Nanjing University of Aeronautics and Astronautics) shlibektaha@gmail.com

Abdalla I. Fadel (Professor - School of Engineering and Applied Science/ Libyan Academy) fadel.abdalla@zu.edu.ly

Manal Shlibek (Engineer at GECOL- MSc- Electrical Engineering/ Libyan Academy) manal.shlibek@gmail.com

Distribution System Operation and Performance Enhancement, Applying Distribution Generation DG.s Penetration Based On Optimal Power Flow Analysis

 Applying of distributed generations (DG) is a new approach and challenge for enhancement of a traditional electric power system operation by power injections from DGs that changes network power flows, modifying energy losses and voltage profile of the system. Proper locations of DGs in power systems are important to obtain the maximum potential benefits. Also applying optimal power flow (OPF) procedure for system analysis gives the best solution with DG penetration that helps to estimate the size and best locations for DG's. This paper shows a real study using a real part of the Libyan Grid represented by a rural distribution of 30 KV system , that consists a group of substations, and feeder circuits considering, the maximum load connected to buses. In this research a study will performed for enhancing power system operation performance; using OPF based on Newton- Raphson extended method, and applied NEPLAN power analysis software. DG’s will be introduced as a plain DG types that produces active and reactive powers for supporting and enhancing system performance, by choosing the best location and sizes possible according to the network configuration and loading information. 

Eng. Salah Eddin .M. Elgdamsi (GECOL) salah_elgdamsi@yahoo.com

Eng. Abdulkarim .H. Salih (GECOL) kre1920@gmail.com

Prof. Abdalla Idris Fadel (Libyan Academy) abdalla.fadel@academy.edu.ly

Economic Operation of Libyan Western Electric Network Based on OPF and ED Algorithms

The optimal power flow becoming more important because of its capabilities to deal with various situations of power system operation, this problem involves the optimization of objective functions for power generation operation and control. This paper investigating the optimal power flow (OPF) and Economic Dispatch (ED) of the western area of Libyan national network of (220 &400kv) system for optimizing power system losses and reducing fuel costs, by using different scenarios to keep the network operating in good condition, OPF and (ED) are formulated as an optimization problem for minimizing the total fuel cost and power loss of all committed plants while meeting the network operation constraints. Applying the OPF and ED as base for system analysis with a unified power flow controller (UPFC) solved most power system problems and maintains system stability even during difficult operation condition. 

Eng.Mahmud.A.Abotraba (Exprogroup international oil and marketing company) mabotraba1981@gmail.com

Prof.Abdalla.I.Fadel (Professor of Electrical and Electronic Engineering) abdalla.fadel@academy.edu.ly

Investigation the Optimum Frequency Response of Transceiver Performances

In discrete multitone (DMT) transceivers an intelligent guard time sequence, called a cyclic prefix (CP), is inserted between symbols to ensure that samples from one symbol do not interfere with the samples of another symbol. The length of the CP is determined by the length of the impulse response of the effective physical channel. Using a long CP reduces the throughput of the transceiver, To avoid using a long CP, a short time-domain finite impulse response (FIR) filter is used to shorten the effective channels impulse response. This paper explores various methods of determining the coefficients for this time-domain filter. An optimal shortening and a least-squares (LS) approach are developed for shortening the channel's impulse response. To provide a computationally efficient algorithm a variation of the LS approach is explored. In full-duplex transceivers the length of the effective echo path impacts the computational requirements of the transceiver. A new paradigm of joint shortening is introduced and three methods are developed to jointly shorten the channel and the echo impulse responses in order to reduce the length of the CP and reduce computational requirements for the echo canceller

Amaal O. Althini (1Om-Alrrabea Faculty of Science and Technology Sorman –Libya) sial.mh2013@gmail.com

Abdulatif A. Shaban (Janzour Collage of Education, University of Tripoli Tripoli, Libya) latif1995@yahoo.co.uk

Hana H.Saleh (Benghazi University, Faculty of Education- Qmins) cleverageh@gmail.com

Renewable Energy Technologies as Distribution Generation and its Effect on Electrical Distribution System in a Semi Desert Area

This paper focuses on renewable energy generated generation (DG) systems that will satisfy the operational requirement in different cases. The global need for a sustainable energy system is becoming very important over the next few years due to the recent attention on conventional energy resources such as fossil fuels which have effects on the environment. The renewable energy technologies such as solar energy systems are becoming more critical energy technology of the generation system. However, selecting optimal sites for DG systems depends on the local conditions and potential of renewable energy. In this work, a semi-desert area network of Libyan electrical distribution systems has been chosen as a case study. The objectives of this work are to observe the effects of DG systems in an electrical distribution system and also to present its different performance levels. Furthermore, this paper presents the implementation of a Newton Raphson method using NEPLAN software to analyze the transition and the use of sub-transmission networks, interconnecting the DG units for a semidesert area in Libya. The simulation results are analyzed and discussed to make a suggestion for adapting this method in using the sub-transmission networks to interconnect the DG systems. 

Abdalfettah Asharaa (School of Engineering and Applied Science, The Libyan Academy, Libya, Tripoli) Asharaa12345@gmail.com

Abdalla I. Fadel (University of Bradford, Bradford, West Yorkshire, Bradford, United Kingdom2)

Adnan Asharaa (College of Electrical Engineering, Bani Walid University, Bani Walid, Libya)

Raed Abd-Alhameed (The University of Tripoli, Libya, Tripoli)

Simulation of Pressurizer for Steam Generator Tube Rupture of St. Prairie Island Nuclear Generating Plant, USA, using the MATLAB Environment

The objective of this paper is to develop a simulator of a pressurizer component of a pressurized water reactor (PWR) power plant. The mathematical model of this simulator is developed from basic principle of physics, where mass and energy conservations were applied to a control volume. The pressurizer module is verified through simulation of St. Prairie Island Nuclear Generating Plant tube rupture accident. The boundary conditions required for the simulation of the pressurizer module were extracted from simulations of the accident using RELAP code. The module response predicted the trend of the pressure, quality, and water level in the pressurizer. The programing was performed under MATLAB environment. Analysis performed for the simulation of the pressurizer revealed an interesting linear relation between the derived coefficients of the model and the system state variables of the pressure or the quality. This suggests that improvement of the model in terms of speed of computation can be attained if such coefficient fitting to either of the state variables is performed.

Hameda M. Shahat (Atomic Energy Establishment of Libya)

Bahlul Abani Embarka embarka.ateia1979@gmail.com

kh. milad

Wajdi M. Ratemi (University of Tripoli - Nuclear Eng. Dept)

Optimal re-planning of a 30kv distribution network with DG penetration Based on economic dispatch and optimal load flow

 In this paper an optimal and economic dispatch study will be performed for re-planning a large section of Libyan Electrical distribution network, that include Electrical power plant ,considering distribution generation (DG) penetration method instead of a conventional re-planning methods, such as the expanding and adding methods that needs efforts and time. The new approaches of electrical distribution system of economic operation and replanning are the most efficient and interested to the electric power utilities now days. The availability of high performance software's such as the MATLAB and NIPLAN helps in redesigning and replanning of electric power system for enhancing performance and solving system problems. Libyan electric distribution networks are suffering many problems of voltage limits violation, high system losses and low system performance. The optimal power flow (OPF) with economic dispatch (ED) methods will be used to show the benefits of using DG penetration. Alzahra 30KV electric system is taken as the case study including AL Zahra power plant, with different operation cases are considered includes the operation of the network as an isolated grid, considering DG penetration during peak loads with OPF analyses. This study shows the great effect of DG pentration with ED and OPF methods for reducing fuel costs and power losses as well as increasing the power transfer for system transmission, the reduction of 14.5% of fuel consumption is achieved, and about 70% of total power losses in the studied network is reduced with an excellent performance of system voltage profile and line loadings

Eng. Abdulkarim .H. Salih (GECOL) Kre1920@gmail.com

Eng Salah Eddin . M Elgdamsi (GECOL) salah_elgdamsi@yahoo.com

Prof.Dr. Abdalla Idris Fadel (Libyan Academy) fadel@academy.edu.ly

Relationship between Radiation Dose and Image Quality in Lung CT scan In Hospital

The purpose of this study was to determine how changes in radiographic tube current affect patient dose and image quality in unenhanced chest CT examinations. Sixteen sets of CT images were obtained from 160 patients ( 112 Male, 48 Female) undergoing CT-chest scan (using CTscan Model GE-64). For each patient, six images of the same region were obtained at settings between 240 and 300 mAs. CT data were used to reconstruct topographic sections with a field of view limited to the normal contra lateral lung. Images were printed using lung and mediastinal image display settings. Image quality was determined by asking radiologists to assess the perceived level of mottle in CT images. The same set of images were also evaluated by MATLAB(8.1) on the bases of standard deviation , Patient effective doses and risk factor were computed for chest CT examinations performed at each milliampere-second setting Differences in CT image quality for radiographic techniques between 300 and 400 mAs were deemed to be insufficient to justify any additional patient exposure. However, the use of 300 mAs results in an inferior image quality that would justify increased patient exposure. This image quality is confirmed by both methods , radiologist assessment and MATLAB assessment .Therefore, radiographic techniques for unenhanced chest CT examinations can be reduced from 400 to 300 mAs without compromising image quality.

Khadija.M.ABDULSALAM (Libyan Academy, Biomedical Engineering Department, Tripoli- Libya) khadija.abdulsalam@academy.edu.ly

MOHAMMED.A.M (Libyan Academy, Biomedical Engineering Department, Tripoli- Libya)

The Effect of mAs and Slices Number on Image Quality in Pediatrics CT Scan

The goal of clinical computed Tomography(CT) is to produce images of diagnostic quality using the lowest possible radiation exposure, Degradation of image quality, with increased image noise and reduced spatial resolution is a major limitation for radiation dose reduction in (CT). This can be counteracted with new post-processing image filters and iterative reconstruction (IR) algorithms that improve image quality and allow for reduced radiation doses. Implementation of new methods in clinical routine requires prior validation in phantoms and clinical feasibility studies including comprehensive evaluation of diagnostic image quality. The main objectives of this dissertation were to compromise between radiation dose and image quality in brain (CT) scan at different (mAs) and different slice number by using (MATLAB) software for evaluation of image quality. One hundred cases at Alkhalel Hospital were study at radiology department. Brain CT cases were selected from Siemens Computer tomography ( 64 slices ) which is running at different kvp range (80, 110, 130 ) and 50 mAs. Dose measurement for brain CT scan where determined by using CT-Expo software. The results show that the image quality where proportional to the mAs and dose. qualitative and quantitative image quality were in good agreement.

NAJAT. M. ABDULSALAM (Libyan Academy, Physics Department,, Tripoli- Libya) NAJAT.abdulsalam@academy.edu.ly

MOHAMMED.A.M