188 research outputs found
Dynamic Stability Studies Of Generators In Power System Using Fuzzy Logic Controller Based Power System Stabilizer
Excitation systems are affected by low frequency oscillation (LFO)when they are subjected to small perturbations.Damping during the LFOis enhanced via the addition of power system stabilizer (PSS) to the excitation system.This research entails a study on fuzzy logic controller power system stabilizer (FLCPSS) for the purpose of enhancing the stability of a single machine power system.In order to accomplish the stability enhancement,two approaches were used to design fuzzy logic controller (FLC).The first approach includes the use ofgenetic algorithm (GA) to design the PSS.The second approach entails the use of particle swarm optimization (PSO) to design the PSS.The performance of these two approaches is compared with the systemand without PSS.The stabilizing signals were computed using the fuzzy membership functions depending on these variables.The simulations were tested under different operating conditions and also tested with different membership functions.The simulation is implemented using Matlab /Simulink and the results have been found to be quite good and satisfactory.Electro-mechanical oscillations were created in the event of trouble or when there was high power transfer through weak tie-line in the machines of an interrelated power network.This research presents an analysis on the change of speed (Δω), change of angle position (Δδ) and tie-line power flow (Δp).FLC which includes two areas of symmetrical systems are connected via tie-line to identify the performance of the controllers.Simulation results of the fuzzy logic based controller indicate dual inputs of rotor speed deviation and generator’s accelerating power.Two generators have been used to control the arrangement in the tie-line system.The single fuzzy logic controller (S-FLC) has been used as a primary controller and the double fuzzy logic controller(D-FLC) has been used as a secondary controller.Additionally,the system shows a comparison between the two controllers,namely the S-FLC and D-FLC which have been used to achieve the best results.Notably, the double fuzzy controller has been found to have a greater effect on the multi-machine system and it is smoother than the single fuzzy controller as it increased the damping of the speed Δω and rotorangle (degree) Δδ. Its simplicity has made it to be a good controller.In conclusion,much better response can be attained from the S-FLC) if there is careful timing of the scaling factors
Aerodynamic design and performance investigation of an axial turbocharger turbine for automotive application
In recent years, developments of vehicle downsizing promote the developers to improve the performance of current turbocharging technology. Due to drawbacks transient response of conventional radial turbine used in turbocharging techniques, preliminary design of axial turbine was proposed, in order to achieve highest performance of turbocharger axial turbine. In this study, the optimal design methodology, based NACA profile blade of a single stage axial turbine for turbocharger system. Therefore, simulation analysis of steady state three dimensional flow carried out by highly reliable for calculation, computational fluid dynamic (CFD), using ANSYS CFX, to be evaluated the stage overall aerodynamic performance of the axial turbine stage. Analysis results, gave a more details of flow behaviour such as, flow separation, vortexes and performance characteristics. Moreover, it is found the pressure load for less blades, it's too low on each blade, and a reasonable pressure blade load on a single blade was therefore seen to be too high for more blades, resulting in loss of Boundary layer of the blade, flow of tip leakage and Secondary flow. Hence, noticeably, it was observed that the aerodynamic performance of turbocharger axial turbine model were predicted numerically such as, total-total Polytropic efficiency (84.64) % and shaft output power (187) kW at (80k) rpm
Soft Pre-Open Sets In Soft Bitopological Spaces
In this work , I introduce the concept of soft bitopological space on a soft set and some definitions on soft pre-open set on soft bitopological space . Also introduce soft pre separation axioms , Spre- , Spre- and Spre- , with study some properties in soft bitopological space
Islamic finance: Meeting Global Aspirations and Growth Potential - UK Model
The purpose of this research is to describe the Islamic financial market and products, with particular emphasis on the growth of Islamic finance in the UK market. The analytical descriptive approach has been used because it will help to collect quantitative and qualitative data to answer the research question or test the research hypothesis. The results indicate that Islamic and traditional banks with the Islamic window promote investment in the UK through the financing of real estate, insurance services and financing of transport projects without interest charges on loans. (FSA) Encourage the Government to develop Islamic banking, develop market and demand, and develop Islamic finance products and services that contribute to the growth of Islamic banking services in the United Kingdom
A Supervisory Control and Data Acquisition (Scada) for Water Distribution System of Gaza City
Gaza has scarce water resources. At present, there are 40 wells that are supposed to supply adequate water from the aquifer to the public through the water distribution network. However, the pumping stations at these wells along with the distribution network are managed manually by operators in a primitive manner. During peak consumption periods, which may last for weeks, water is not delivered to wide areas and resources are not distributed evenly to public. Operators try hardly to achieve fairness by manually controlling gate valves along with pumping stations. The aim of this research is to design a Supervisory Control and Data Acquisition (SCADA) system for managing the water pumping stations in Gaza. This system is expected to increase customer satisfaction, reduce water distribution cost and provide an accurate overview of the plants’ operations. Moreover, SCADA stores valuable information about the water system performance. This data is necessary for efficient development of the existent distribution system in a way that meets population growth
Phase Measurement Units based FACT’s Devices for the Improvement of Power Systems Networks Controllability
This paper describes the importance of FACTS devices; it presents the outcome of the study of its reflectance on the performance of power system networks. It seeks to increase and guarantee the fact and accuracy of response systems under disturbance conditions when the phase measurement units are introduced as Real-Time Measurement (RTM) stations. This paper also describes the importance of FACTS devices. The combination of FACTS devices and PMUs is presented to increase the controllability performance of power systems. This paper demonstrates how PMUs measure voltage, current and their angles. It provides, through a communication link, a Phase Angle Data Concentrator (PDC) to make an appropriate decision to correct the power system state using the FACTS device (TCSC). We utilized the Graph-Theoretic Algorithm to optimize the number and location of PMUs. The technique proposed was tested on the Iraqi National Super Grid’s 24bus network, Diyala City’s regional 10bus network and the 14bus IEEE standard test system. The MATLAB/PSAT package was utilized for the simulation of results. It is evident that our proposed algorithm and technique achieved the purpose of this paper as confirmed by the level of accuracy of the results obtained from most of the cases tested
The extent of using managerial accounting innovations in the government sector in Iraq
The study aims to show the extent to which the government sector in Iraq uses managerial accounting innovations, the most important of which being VCA - Value Chain Analysis, TDABC – Time-Driven Activity-Based Costing Method, BM – Benchmarking Method, TC - Target Cost Method, SWOT – Strategic Analysis Method, while indicating factors that hinder their application. As the application of these methods leads to the development of accounting information systems in a manner that ensures rationalization of costs and strengthening control over them, and the provision of appropriate information that contributes to rationalizing the correct administrative decisions, a questionnaire was prepared for this purpose and distributed to 500 account and production managers in governmental sectors in Iraq as well as the industrial, agricultural and service sectors. The study found that the government sector in Iraq applies some of these methods, but in a limited manner, as a result of constraints that limit the use of these method
Survey on encode biometric data for transmission in wireless communication networks
The aim of this research survey is to review an enhanced model supported by artificial intelligence to encode biometric data for transmission in wireless communication networks can be tricky as performance decreases with increasing size due to interference, especially if channels and network topology are not selected carefully beforehand. Additionally, network dissociations may occur easily if crucial links fail as redundancy is neglected for signal transmission. Therefore, we present several algorithms and its implementation which addresses this problem by finding a network topology and channel assignment that minimizes interference and thus allows a deployment to increase its throughput performance by utilizing more bandwidth in the local spectrum by reducing coverage as well as connectivity issues in multiple AI-based techniques. Our evaluation survey shows an increase in throughput performance of up to multiple times or more compared to a baseline scenario where an optimization has not taken place and only one channel for the whole network is used with AI-based techniques. Furthermore, our solution also provides a robust signal transmission which tackles the issue of network partition for coverage and for single link failures by using airborne wireless network. The highest end-to-end connectivity stands at 10 Mbps data rate with a maximum propagation distance of several kilometers. The transmission in wireless network coverage depicted with several signal transmission data rate with 10 Mbps as it has lowest coverage issue with moderate range of propagation distance using enhanced model to encode biometric data for transmission in wireless communication
Heat Transfer Augmentation in Gas Turbine Blade Rectangular Passages Using Circular Ribs with Fins
في هذا البحث تم تصميم وبناء نظام تجريبي لمحاكاه ظروف تبريد ريشه التوربين الغازي حيث كانت درجه حراره هواء التبريد الداخل (300 كلفن ) ورقم رينولد (7901) ودرجه الحراره المحيطه (673كلفن) وتم اجراء المحاكاه العدديه باستخدام برنامج الفلونت (14.5) حيث تم دراسه تأثير الاضلاع الدائريه ذات الزعانف الوسطيه خلال مجرى مستطيل بابعاد (30 *60 ملم) وبسمك (1.5 ملم) وطول (0,5 م) على الجريان وانتقال الحراره .لاحظنا ان باستخدام الاضلاع الدائريه ذات الزعانف الوسطيه تم زياده حراره هواء التبريد الداخل بنسبه (10.22%) و نقصان بدرجه السطح الداخلي للقناه بنسبه (6.15%) وكان معامل الاداء الحراري اكبر من واحد وهذا يدل على ان الاضلاع الدائريه حسن بانتقال الحراره من خلال زياده المساحه السطحيه للانتقال وزياده الاضطراب الذي يؤدي الى زياده الخلط .In this paper, an experimental system was designed and built to simulate conditions in the gas turbine blade cooling and run the experimental part. Boundary conditions are: inlet coolant air temperature is 300K with Reynolds numbers (Re=7901) .The surrounding constant hot air temperatures was (673 K).The numerical simulations were done by using software FLUENT version (14.5), in this part, it was presented the effect of using circular ribs having middle fin fitted in rectangular passage channel on fluid flow and heat transfer characteristics. Ribs used with pitch-rib height of 10, rectangular channel of (30x60 mm) cross section, 1.5 mm duct thickness and 0.5 m long. The temperature, velocity distribution contours, cooling air temperature distribution at the duct centerline, the inner wall surface temperature of the duct, and thermal performance factor are presented in this paper. it can be seen that the duct with all ribs with middle fins was the better case which leads to increase the coolant air temperature by (10.22 %) and decrease the inner wall temperature by (6.15 % ). The coolant air flow velocity seems to be accelerated and decelerated through the channel in the presence of ribs, so it was shown that the thermal performance factor along the duct is larger than 1, this is due to the fact that the ribs create turbulent conditions and increasing thermal surface area, and thus increasing heat transfer coefficient than the smooth channel
HSO: A Hybrid Swarm Optimization Algorithm for Re-Ducing Energy Consumption in the Cloudlets
Mobile Cloud Computing (MCC) is an emerging technology for the improvement of mobile service quality. MCC resources are dynamically allocated to the users who pay for the resources based on their needs. The drawback of this process is that it is prone to failure and demands a high energy input. Resource providers mainly focus on resource performance and utilization with more consideration on the constraints of service level agreement (SLA). Resource performance can be achieved through virtualization techniques which facilitates the sharing of resource providers’ information between different virtual machines. To address these issues, this study sets forth a novel algorithm (HSO) that optimized energy efficiency resource management in the cloud; the process of the proposed method involves the use of the developed cost and runtime-effective model to create a minimum energy configuration of the cloud compute nodes while guaranteeing the maintenance of all minimum performances. The cost functions will cover energy, performance and reliability concerns. With the proposed model, the performance of the Hybrid swarm algorithm was significantly increased, as observed by optimizing the number of tasks through simulation, (power consumption was reduced by 42%). The simulation studies also showed a reduction in the number of required calculations by about 20% by the inclusion of the presented algorithms compared to the traditional static approach. There was also a decrease in the node loss which allowed the optimization algorithm to achieve a minimal overhead on cloud compute resources while still saving energy significantly. Conclusively, an energy-aware optimization model which describes the required system constraints was presented in this study, and a further proposal for techniques to determine the best overall solution was also made
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