Search results for: naval power
5601 Defect Identification in Partial Discharge Patterns of Gas Insulated Switchgear and Straight Cable Joint
Authors: Chien-Kuo Chang, Yu-Hsiang Lin, Yi-Yun Tang, Min-Chiu Wu
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With the trend of technological advancement, the harm caused by power outages is substantial, mostly due to problems in the power grid. This highlights the necessity for further improvement in the reliability of the power system. In the power system, gas-insulated switches (GIS) and power cables play a crucial role. Long-term operation under high voltage can cause insulation materials in the equipment to crack, potentially leading to partial discharges. If these partial discharges (PD) can be analyzed, preventative maintenance and replacement of equipment can be carried out, there by improving the reliability of the power grid. This research will diagnose defects by identifying three different defects in GIS and three different defects in straight cable joints, for a total of six types of defects. The partial discharge data measured will be converted through phase analysis diagrams and pulse sequence analysis. Discharge features will be extracted using convolutional image processing, and three different deep learning models, CNN, ResNet18, and MobileNet, will be used for training and evaluation. Class Activation Mapping will be utilized to interpret the black-box problem of deep learning models, with each model achieving an accuracy rate of over 95%. Lastly, the overall model performance will be enhanced through an ensemble learning voting method.Keywords: partial discharge, gas-insulated switches, straight cable joint, defect identification, deep learning, ensemble learning
Procedia PDF Downloads 695600 Exploring Probabilistic Models for Transient Stability Analysis of Renewable-Dominant Power Grid
Authors: Phuong Nguyen
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Along with the ongoing energy transition, the electrical power system is getting more vulnerable with the increasing penetration of renewable energy sources (RES). By replacing a large amount of fossil fuel-based power plants with RES, the rotating mass of the power grid is decreasing drastically, which has been reported by a number of system operators. This leads to a huge challenge for operators to secure the operation of their grids in all-time horizon ranges, from sub-seconds to minutes and even hours. There is a need to revise the grid capabilities in dealing with transient (angle) stability and voltage dynamics. While the traditional approaches relied on deterministic scenarios (worst-case scenarios), there is also a need to cover a whole range of probabilities regarding a wide range of uncertainties coming from massive RES units. To contribute to handle these issues, this paper aims to focus on developing a new analytical approach for transient stability.Keywords: transient stability, uncertainties, renewable energy sources, analytical approach
Procedia PDF Downloads 625599 A Macroeconomic Analysis of Defense Industry: Comparisons, Trends and Improvements in Brazil and in the World
Authors: J. Fajardo, J. Guerra, E. Gonzales
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This paper will outline a study of Brazil's industrial base of defense (IDB), through a bibliographic research method, combined with an analysis of macroeconomic data from several available public data platforms. This paper begins with a brief study about Brazilian national industry, including analyzes of productivity, income, outcome and jobs. Next, the research presents a study on the defense industry in Brazil, presenting the main national companies that operate in the aeronautical, army and naval branches. After knowing the main points of the Brazilian defense industry, data on the productivity of the defense industry of the main countries and competing companies of the Brazilian industry were analyzed, in order to summarize big cases in Brazil with a comparative analysis. Concerned the methodology, were used bibliographic research and the exploration of historical data series, in order to analyze information, to get trends and to make comparisons along the time. The research is finished with the main trends for the development of the Brazilian defense industry, comparing the current situation with the point of view of several countries.Keywords: economics of defence, industry, trends, market
Procedia PDF Downloads 1455598 Heuristics for Optimizing Power Consumption in the Smart Grid
Authors: Zaid Jamal Saeed Almahmoud
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Our increasing reliance on electricity, with inefficient consumption trends, has resulted in several economical and environmental threats. These threats include wasting billions of dollars, draining limited resources, and elevating the impact of climate change. As a solution, the smart grid is emerging as the future power grid, with smart techniques to optimize power consumption and electricity generation. Minimizing the peak power consumption under a fixed delay requirement is a significant problem in the smart grid. In addition, matching demand to supply is a key requirement for the success of the future electricity. In this work, we consider the problem of minimizing the peak demand under appliances constraints by scheduling power jobs with uniform release dates and deadlines. As the problem is known to be NP-Hard, we propose two versions of a heuristic algorithm for solving this problem. Our theoretical analysis and experimental results show that our proposed heuristics outperform existing methods by providing a better approximation to the optimal solution. In addition, we consider dynamic pricing methods to minimize the peak load and match demand to supply in the smart grid. Our contribution is the proposal of generic, as well as customized pricing heuristics to minimize the peak demand and match demand with supply. In addition, we propose optimal pricing algorithms that can be used when the maximum deadline period of the power jobs is relatively small. Finally, we provide theoretical analysis and conduct several experiments to evaluate the performance of the proposed algorithms.Keywords: heuristics, optimization, smart grid, peak demand, power supply
Procedia PDF Downloads 825597 Water Saving in Electricity Generation System Considering Natural Gas Limitation
Authors: Mehdi Ganjkhani, Sobhan Badakhshan, Seyedvahid Hosseini
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Power plants exploit striking proportion of underground water consumption. Correspondingly, natural gas-fired power plants need less water than the other conventional power plants. Therefore, shifting unit commitment planning toward these power plants would help to save water consumption. This paper discusses the impacts of water consumption limitation on natural gas consumption and vice versa as a short-term water consumption management solution. To do so, conventional unit commitment problem is extended by adding water consumption and natural gas constraints to the previous constrains. The paper presents the impact of water saving on natural gas demands as well as natural gas shortage on water demand. Correspondingly, the additional cost of electricity production according to the aforementioned constraints is evaluated. Finally, a test system is applied to investigate potentials and impacts of water saving and natural gas shortage. Different scenarios are conducted and the results are presented. The results of the study illustrate that in order to use less water for power production it needs to use more natural gas. Meanwhile, natural gas shortage causes to utilize more amount of water in aggregate.Keywords: electric energy generation system, underground water sources, unit commitment, water consumption saving, natural gas
Procedia PDF Downloads 1815596 Magnetomechanical Effects on MnZn Ferrites
Authors: Ibrahim Ellithy, Mauricio Esguerra, , Rewanth Radhakrishnan
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In this study, the effects of hydrostatic stress on the magnetic properties of MnZn ferrite rings of different power grades, were measured and analyzed in terms of the magneto-mechanical effect on core losses was modeled via the Hodgdon-Esguerra hysteresis model. The results show excellent agreement with the model and a correlation between the permeability drop and the core loss increase in dependence of the material grade properties. These results emphasize the vulnerabilities of MnZn ferrites when subjected to mechanical perturbations, especially in real-world scenarios like under-road embedding for WPT.Keywords: hydrostatic stress, power ferrites, core losses, wireless power transfer
Procedia PDF Downloads 585595 Design and Simulation of Unified Power Quality Conditioner based on Adaptive Fuzzy PI Controller
Authors: Brahim Ferdi, Samira Dib
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The unified power quality conditioner (UPQC), a combination of shunt and series active power filter, is one of the best solutions towards the mitigation of voltage and current harmonics problems in distribution power system. PI controller is very common in the control of UPQC. However, one disadvantage of this conventional controller is the difficulty in tuning its gains (Kp and Ki). To overcome this problem, an adaptive fuzzy logic PI controller is proposed. The controller is composed of fuzzy controller and PI controller. According to the error and error rate of the control system and fuzzy control rules, the fuzzy controller can online adjust the two gains of the PI controller to get better performance of UPQC. Simulations using MATLAB/SIMULINK are carried out to verify the performance of the proposed controller. The results show that the proposed controller has fast dynamic response and high accuracy of tracking the current and voltage references.Keywords: adaptive fuzzy PI controller, current harmonics, PI controller, voltage harmonics, UPQC
Procedia PDF Downloads 5425594 Novel Spoke-Type BLDC Motor Design for Cost Effective and High Power Density
Authors: Suyong Kim
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Recently because of the rise in the price of rare earth magnet, interest of non-rare earth or less-rare earth motor is growing. Especially to achieve the high power density, Spoke-Type BLDC (Brushless Permanent Magnet) Motor with ferrite permanent magnet are spotlighted. But Spoke-Type Ferrite BLDC Motor has much of magnetic flux leakage in the direction of rotor shaft. In order to solve this problem, there are two conventional ways. But conventional ways bring the increases of product cost or the decreases of the power density. Therefore, this paper proposes new Spoke-Type BLDC Rotor shape that has the advantages of both conventional methods. The new shape is consists of a one-piece core. The inside and the outside of the rotor are open alternately. So it can take reduced production cost and high power density.Keywords: motor, BLDC, spoke, ferrite
Procedia PDF Downloads 5595593 Low Power, Highly Linear, Wideband LNA in Wireless SOC
Authors: Amir Mahdavi
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In this paper a highly linear CMOS low noise amplifier (LNA) for ultra-wideband (UWB) applications is proposed. The proposed LNA uses a linearization technique to improve second and third-order intercept points (IIP3). The linearity is cured by repealing the common-mode section of all intermodulation components from the cascade topology current with optimization of biasing current use symmetrical and asymmetrical circuits for biasing. Simulation results show that maximum gain and noise figure are 6.9dB and 3.03-4.1dB over a 3.1–10.6 GHz, respectively. Power consumption of the LNA core and IIP3 are 2.64 mW and +4.9dBm respectively. The wideband input impedance matching of LNA is obtained by employing a degenerating inductor (|S11|<-9.1 dB). The circuit proposed UWB LNA is implemented using 0.18 μm based CMOS technology.Keywords: highly linear LNA, low-power LNA, optimal bias techniques
Procedia PDF Downloads 2735592 DG Allocation to Reduce Production Cost by Reducing Losses in Radial Distribution Systems Using Fuzzy
Authors: G. V. Siva Krishna Rao, B. Srinivasa Rao
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Electrical energy is vital in every aspect of day-to-day life. Keen interest is taken on all possible sources of energy from which it can be generated and this led to the encouragement of generating electrical power using renewable energy resources such as solar, tidal waves and wind energy. Due to the increasing interest on renewable sources in recent times, the studies on integration of distributed generation to the power grid have rapidly increased. Distributed Generation (DG) is a promising solution to many power system problems such as voltage regulation, power loss and reduction in operational cost, etc. To reduce production cost, it is important to minimize the losses by determining the location and size of local generators to be placed in the radial distribution systems. In this paper, reduction of production cost by optimal size of DG unit operated at optimal power factor is dealt. The optimal size of the DG unit is calculated analytically using approximate reasoning suitable nodes and DG placement to minimize production cost with minimum loss is determined by fuzzy technique. Total Cost of Power generation is compared with and without DG unit for 1 year duration. The suggested method is programmed under MATLAB software and is tested on IEEE 33 bus system and the results are presented.Keywords: distributed generation, operational cost, exact loss formula, optimum size, optimum location
Procedia PDF Downloads 4805591 Evaluating the Effect of Splitting Wind Farms on Power Output
Authors: Nazanin Naderi, Milton Smith
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Since worldwide demand for renewable energy is increasing rapidly because of the climate problem and the limitation of fossil fuels, technologies of alternative energy sources have been developed and the electric power network now includes renewable energy resources such as wind energy. Because of the huge advantages that wind energy has, like reduction in natural gas use, price pressure, emissions of greenhouse gases and other atmospheric pollutants, electric sector water consumption and many other contributions to the nation’s economy like job creation it has got too much attention these days from different parts of the world especially in the United States which is trying to provide 20% of the nation’s energy from wind by 2030. This study is trying to evaluate the effect of splitting wind farms on power output. We are trying to find if we can get more output by installing wind turbines in different sites rather than installing all wind turbines in one site. Five potential sites in Texas have been selected as a case study and two years wind data has been gathered for these sites. Wind data are analyzed and effect of correlation between sites on power output has been evaluated. Standard deviation and autocorrelation effect has also been considered for this study. The paper has been organized as follows: After the introduction the second section gives a brief overview of wind analysis. The third section addresses the case study and evaluates correlation between sites, auto correlation of sites and standard deviation of power output. In section four we describe the results.Keywords: auto correlation, correlation between sites, splitting wind farms, power output, standard deviation
Procedia PDF Downloads 5805590 Thermal Effect in Power Electrical for HEMTs Devices with InAlN/GaN
Authors: Zakarya Kourdi, Mohammed Khaouani, Benyounes Bouazza, Ahlam Guen-Bouazza, Amine Boursali
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In this paper, we have evaluated the thermal effect for high electron mobility transistors (HEMTs) heterostructure InAlN/GaN with a gate length 30nm high-performance. It also shows the analysis and simulated these devices, and how can be used in different application. The simulator Tcad-Silvaco software has used for predictive results good for the DC, AC and RF characteristic, Devices offered max drain current 0.67A; transconductance is 720 mS/mm the unilateral power gain of 180 dB. A cutoff frequency of 385 GHz, and max frequency 810 GHz These results confirm the feasibility of using HEMTs with InAlN/GaN in high power amplifiers, as well as thermal places.Keywords: HEMT, Thermal Effect, Silvaco, InAlN/GaN
Procedia PDF Downloads 4615589 Regional Pole Placement by Saturated Power System Stabilizers
Authors: Hisham M. Soliman, Hassan Yousef
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This manuscript presents new results on design saturated power system stabilizers (PSS) to assign system poles within a desired region for achieving good dynamic performance. The regional pole placement is accomplished against model uncertainties caused by different load conditions. The design is based on a sufficient condition in the form of linear matrix inequalities (LMI) which forces the saturated nonlinear controller to lie within the linear zone. The controller effectiveness is demonstrated on a single machine infinite bus system.Keywords: power system stabilizer, saturated control, robust control, regional pole placement, linear matrix inequality (LMI)
Procedia PDF Downloads 5575588 Harmonic Distortion Analysis in Low Voltage Grid with Grid-Connected Photovoltaic
Authors: Hedi Dghim, Ahmed El-Naggar, Istvan Erlich
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Power electronic converters are being introduced in low voltage (LV) grids at an increasingly rapid rate due to the growing adoption of power electronic-based home appliances in residential grid. Photovoltaic (PV) systems are considered one of the potential installed renewable energy sources in distribution power systems. This trend has led to high distortion in the supply voltage which consequently produces harmonic currents in the network and causes an inherent voltage unbalance. In order to investigate the effect of harmonic distortions, a case study of a typical LV grid configuration with high penetration of 3-phase and 1-phase rooftop mounted PV from southern Germany was first considered. Electromagnetic transient (EMT) simulations were then carried out under the MATLAB/Simulink environment which contain detailed models for power electronic-based loads, ohmic-based loads as well as 1- and 3-phase PV. Note that, the switching patterns of the power electronic circuits were considered in this study. Measurements were eventually performed to analyze the distortion levels when PV operating under different solar irradiance. The characteristics of the load-side harmonic impedances were analyzed, and their harmonic contributions were evaluated for different distortion levels. The effect of the high penetration of PV on the harmonic distortion of both positive and negative sequences was also investigated. The simulation results are presented based on case studies. The current distortion levels are in agreement with relevant standards, otherwise the Total Harmonic Distortion (THD) increases under low PV power generation due to its inverse relation with the fundamental current.Keywords: harmonic distortion analysis, power quality, PV systems, residential distribution system
Procedia PDF Downloads 2565587 Designing a Low Power Consumption Mote in Wireless Sensor Network
Authors: Saidi Nabiha, Khaled Zaatouri, Walid Fajraoui, Tahar Ezzeddine
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The market of Wireless Sensor Network WSN has a great potential and development opportunities. Researchers are focusing on optimization in many fields like efficient deployment and routing protocols. In this article, we will concentrate on energy efficiency for WSN because WSN nodes are habitually deployed in severe No Man’s Land with batteries are not rechargeable, so reducing energy consumption represents an important challenge to extend the life of the network. We will present the design of new WSN mote based on ultra low power STM32L microcontrollers and the ZIGBEE transceiver CC2520. We will compare it to existent motes and we will conclude that our mote is promising in energy consumption.Keywords: component, WSN mote, power consumption, STM32L, sensors, CC2520
Procedia PDF Downloads 5695586 Natural Convection in Wavy-Wall Cavities Filled with Power-Law Fluid
Authors: Cha’o-Kuang Chen, Ching-Chang Cho
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This paper investigates the natural convection heat transfer performance in a complex-wavy-wall cavity filled with power-law fluid. In performing the simulations, the continuity, Cauchy momentum and energy equations are solved subject to the Boussinesq approximation using a finite volume method. The simulations focus specifically on the effects of the flow behavior index in the power-law model and the Rayleigh number on the flow streamlines, isothermal contours and mean Nusselt number within the cavity. The results show that pseudoplastic fluids have a better heat transfer performance than Newtonian or dilatant fluids. Moreover, it is shown that for Rayleigh numbers greater than Ra=103, the mean Nusselt number has a significantly increase as the flow behavior index is decreased.Keywords: non-Newtonian fluid, power-law fluid, natural convection, heat transfer enhancement, cavity, wavy wall
Procedia PDF Downloads 2565585 Design and Analysis of Electric Power Production Unit for Low Enthalpy Geothermal Reservoir Applications
Authors: Ildar Akhmadullin, Mayank Tyagi
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The subject of this paper is the design analysis of a single well power production unit from low enthalpy geothermal resources. A complexity of the project is defined by a low temperature heat source that usually makes such projects economically disadvantageous using the conventional binary power plant approach. A proposed new compact design is numerically analyzed. This paper describes a thermodynamic analysis, a working fluid choice, downhole heat exchanger (DHE) and turbine calculation results. The unit is able to produce 321 kW of electric power from a low enthalpy underground heat source utilizing n-Pentane as a working fluid. A geo-pressured reservoir located in Vermilion Parish, Louisiana, USA is selected as a prototype for the field application. With a brine temperature of 126℃, the optimal length of DHE is determined as 304.8 m (1000ft). All units (pipes, turbine, and pumps) are chosen from commercially available parts to bring this project closer to the industry requirements. Numerical calculations are based on petroleum industry standards. The project is sponsored by the Department of Energy of the US.Keywords: downhole heat exchangers, geothermal power generation, organic rankine cycle, refrigerants, working fluids
Procedia PDF Downloads 3115584 Improvising Grid Interconnection Capabilities through Implementation of Power Electronics
Authors: Ashhar Ahmed Shaikh, Ayush Tandon
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The swift reduction of fossil fuels from nature has crucial need for alternative energy sources to cater vital demand. It is essential to boost alternative energy sources to cover the continuously increasing demand for energy while minimizing the negative environmental impacts. Solar energy is one of the reliable sources that can generate energy. Solar energy is freely available in nature and is completely eco-friendly, and they are considered as the most promising power generating sources due to their easy availability and other advantages for the local power generation. This paper is to review the implementation of power electronic devices through Solar Energy Grid Integration System (SEGIS) to increase the efficiency. This paper will also concentrate on the future grid infrastructure and various other applications in order to make the grid smart. Development and implementation of a power electronic devices such as PV inverters and power controllers play an important role in power supply in the modern energy economy. Solar Energy Grid Integration System (SEGIS) opens pathways for promising solutions for new electronic and electrical components such as advanced innovative inverter/controller topologies and their functions, economical energy management systems, innovative energy storage systems with equipped advanced control algorithms, advanced maximum-power-point tracking (MPPT) suited for all PV technologies, protocols and the associated communications. In addition to advanced grid interconnection capabilities and features, the new hardware design results in small size, less maintenance, and higher reliability. The SEGIS systems will make the 'advanced integrated system' and 'smart grid' evolutionary processes to run in a better way. Since the last few years, there was a major development in the field of power electronics which led to more efficient systems and reduction of the cost per Kilo-watt. The inverters became more efficient and had reached efficiencies in excess of 98%, and commercial solar modules have reached almost 21% efficiency.Keywords: solar energy grid integration systems, smart grid, advanced integrated system, power electronics
Procedia PDF Downloads 1725583 Simulation Study of a Fault at the Switch on the Operation of the Doubly Fed Induction Generator Based on the Wind Turbine
Authors: N. Zerzouri, N. Benalia, N. Bensiali
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This work is devoted to an analysis of the operation of a doubly fed induction generator (DFIG) integrated with a wind system. The power transfer between the stator and the network is carried out by acting on the rotor via a bidirectional signal converter. The analysis is devoted to the study of a fault in the converter due to an interruption of the control of a semiconductor. Simulation results obtained by the MATLAB / Simulink software illustrate the quality of the power generated at the default.Keywords: doubly fed induction generator (DFIG), wind power generation, back to back PWM converter, default switching
Procedia PDF Downloads 4595582 Investigation of Enhanced Geothermal System with CO2 as Working Fluid
Authors: Ruina Xu, Peixue Jiang, Feng Luo
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The novel concept of enhanced geothermal system with CO2 instead of water as working fluid (CO2-EGS) has attracted wide attention due to additional benefit of CO2 geological storage during the power generation process. In this research, numerical investigation on a doublet CO2-EGS system is performed, focusing on the influence of the injection/production well perforation location in the targeted geothermal reservoir. Three different reservoir inlet and outlet boundary conditions are used in simulations since the well constrains are different in reality. The results show that CO2-EGS system performance of power generation and power cost vary greatly among cases of different wells perforation locations, and the optimum options under different boundary conditions are also different.Keywords: Enhanced Geothermal System, supercritical CO2, heat transfer, CO2-EGS
Procedia PDF Downloads 2805581 BLDC Motor Driven for Solar Photo Voltaic Powered Air Cooling System
Authors: D. Shobha Rani, M. Muralidhar
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Solar photovoltaic (SPV) power systems can be employed as electrical power sources to meet the daily residential energy needs of rural areas that have no access to grid systems. In view of this, a standalone SPV powered air cooling system is proposed in this paper, which constitutes a dc-dc boost converter, two voltage source inverters (VSI) connected to two brushless dc (BLDC) motors which are coupled to a centrifugal water pump and a fan blower. A simple and efficient Maximum Power Point Tracking (MPPT) technique based on Silver Mean Method (SMM) is utilized in this paper. The air cooling system is developed and simulated using the MATLAB / Simulink environment considering the dynamic and steady state variation in the solar irradiance.Keywords: boost converter, solar photovoltaic array, voltage source inverter, brushless DC motor, solar irradiance, maximum power point tracking, silver mean method
Procedia PDF Downloads 2665580 Photovoltaic Maximum Power-Point Tracking Using Artificial Neural Network
Authors: Abdelazziz Aouiche, El Moundher Aouiche, Mouhamed Salah Soudani
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Renewable energy sources now significantly contribute to the replacement of traditional fossil fuel energy sources. One of the most potent types of renewable energy that has developed quickly in recent years is photovoltaic energy. We all know that solar energy, which is sustainable and non-depleting, is the best knowledge form of energy that we have at our disposal. Due to changing weather conditions, the primary drawback of conventional solar PV cells is their inability to track their maximum power point. In this study, we apply artificial neural networks (ANN) to automatically track and measure the maximum power point (MPP) of solar panels. In MATLAB, the complete system is simulated, and the results are adjusted for the external environment. The results are better performance than traditional MPPT methods and the results demonstrate the advantages of using neural networks in solar PV systems.Keywords: modeling, photovoltaic panel, artificial neural networks, maximum power point tracking
Procedia PDF Downloads 755579 Smart Defect Detection in XLPE Cables Using Convolutional Neural Networks
Authors: Tesfaye Mengistu
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Power cables play a crucial role in the transmission and distribution of electrical energy. As the electricity generation, transmission, distribution, and storage systems become smarter, there is a growing emphasis on incorporating intelligent approaches to ensure the reliability of power cables. Various types of electrical cables are employed for transmitting and distributing electrical energy, with cross-linked polyethylene (XLPE) cables being widely utilized due to their exceptional electrical and mechanical properties. However, insulation defects can occur in XLPE cables due to subpar manufacturing techniques during production and cable joint installation. To address this issue, experts have proposed different methods for monitoring XLPE cables. Some suggest the use of interdigital capacitive (IDC) technology for online monitoring, while others propose employing continuous wave (CW) terahertz (THz) imaging systems to detect internal defects in XLPE plates used for power cable insulation. In this study, we have developed models that employ a custom dataset collected locally to classify the physical safety status of individual power cables. Our models aim to replace physical inspections with computer vision and image processing techniques to classify defective power cables from non-defective ones. The implementation of our project utilized the Python programming language along with the TensorFlow package and a convolutional neural network (CNN). The CNN-based algorithm was specifically chosen for power cable defect classification. The results of our project demonstrate the effectiveness of CNNs in accurately classifying power cable defects. We recommend the utilization of similar or additional datasets to further enhance and refine our models. Additionally, we believe that our models could be used to develop methodologies for detecting power cable defects from live video feeds. We firmly believe that our work makes a significant contribution to the field of power cable inspection and maintenance. Our models offer a more efficient and cost-effective approach to detecting power cable defects, thereby improving the reliability and safety of power grids.Keywords: artificial intelligence, computer vision, defect detection, convolutional neural net
Procedia PDF Downloads 985578 Parameters Estimation of Power Function Distribution Based on Selective Order Statistics
Authors: Moh'd Alodat
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In this paper, we discuss the power function distribution and derive the maximum likelihood estimator of its parameter as well as the reliability parameter. We derive the large sample properties of the estimators based on the selective order statistic scheme. We conduct simulation studies to investigate the significance of the selective order statistic scheme in our setup and to compare the efficiency of the new proposed estimators.Keywords: fisher information, maximum likelihood estimator, power function distribution, ranked set sampling, selective order statistics sampling
Procedia PDF Downloads 4515577 Against the Idea of Public Power as Free Will
Authors: Donato Vese
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According to the common interpretation, in a legal system, public powers are established by law. Exceptions are admitted in an emergency or particular relationship with public power. However, we currently agree that law allows public administration a margin of decision, even in the case of non-discretionary acts. Hence, the administrative decision not exclusively established by law becomes the rule in the ordinary state of things, non-only in state of exception. This paper aims to analyze and discuss different ideas on discretionary power on the Rule of Law and Rechtsstaat. Observing the legal literature in Europe and Nord and South America, discretionary power can be described as follow: it could be considered a margin that law accords to the executive power for political decisions or a choice between different interpretations of vague legal previsions. In essence, this explanation admits for the executive a decision not established by law or anyhow not exclusively established by law. This means that the discretionary power of public administration integrates the law. However, integrating law does not mean to decide according to the law, but it means to integrate law with a decision involving public power. Consequently, discretionary power is essentially free will. In this perspective, also the Rule of Law and the Rechtsstaat are notions explained differently. Recently, we can observe how the European notion of Rechtsstaat is founded on the formal validity of the law; therefore, for this notion, public authority’s decisions not regulated by law represent a problem. Thus, different systems of law integration have been proposed in legal literature, such as values, democracy, reasonableness, and so on. This paper aims to verify how, looking at those integration clauses from a logical viewpoint, integration based on the recourse to the legal system itself does not resolve the problem. The aforementioned integration clauses are legal rules that require hard work to explain the correct meaning of the law; in particular, they introduce dangerous criteria in favor of the political majority. A different notion of public power can be proposed. This notion includes two main features: (a) sovereignty belongs to persons and not the state, and (b) fundamental rights are not grounded but recognized by Constitutions. Hence, public power is a system based on fundamental rights. According to this approach, it can also be defined as the notion of public interest as concrete maximization of fundamental rights enjoyments. Like this, integration of the law, vague or subject to several interpretations, must be done by referring to the system of fundamental individual rights. We can think, for instance, to fundamental rights that are right in an objective view but not legal because not established by law.Keywords: administrative discretion, free will, fundamental rights, public power, sovereignty
Procedia PDF Downloads 995576 Effect of Kinesio Taping on Anaerobic Power and Maximum Oxygen Consumption after Eccentric Exercise
Authors: Disaphon Boobpachat, Nuttaset Manimmanakorn, Apiwan Manimmanakorn, Worrawut Thuwakum, Michael J. Hamlin
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Objectives: To evaluate effect of kinesio tape compared to placebo tape and static stretching on recovery of anaerobic power and maximal oxygen uptake (Vo₂max) after intensive exercise. Methods: Thirty nine untrained healthy volunteers were randomized to 3 groups for each intervention: elastic tape, placebo tape and stretching. The participants performed intensive exercise on the dominant quadriceps by using isokinetic dynamometry machine. The recovery process was evaluated by creatine kinase (CK), pressure pain threshold (PPT), muscle soreness scale (MSS), maximum voluntary contraction (MVC), jump height, anaerobic power and Vo₂max at baseline, immediately post-exercise and post-exercise day 1, 2, 3 and 7. Results: The kinesio tape, placebo tape and stretching groups had significant changes of PPT, MVC, jump height at immediately post-exercise compared to baseline (p < 0.05), and changes of MSS, CK, anaerobic power and Vo₂max at day 1 post-exercise compared to baseline (p < 0.05). There was no significant difference of those outcomes among three groups. Additionally, all experimental groups had little effects on anaerobic power and Vo₂max compared to baseline and compared among three groups (p > 0.05). Conclusion: Kinesio tape and stretching did not improve recovery of anaerobic power and Vo₂max after eccentric exercise compared to placebo tape.Keywords: stretching, eccentric exercise, Wingate test, muscle soreness
Procedia PDF Downloads 1255575 Necessary Condition to Utilize Adaptive Control in Wind Turbine Systems to Improve Power System Stability
Authors: Javad Taherahmadi, Mohammad Jafarian, Mohammad Naser Asefi
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The global capacity of wind power has dramatically increased in recent years. Therefore, improving the technology of wind turbines to take different advantages of this enormous potential in the power grid, could be interesting subject for scientists. The doubly-fed induction generator (DFIG) wind turbine is a popular system due to its many advantages such as the improved power quality, high energy efficiency and controllability, etc. With an increase in wind power penetration in the network and with regard to the flexible control of wind turbines, the use of wind turbine systems to improve the dynamic stability of power systems has been of significance importance for researchers. Subsynchronous oscillations are one of the important issues in the stability of power systems. Damping subsynchronous oscillations by using wind turbines has been studied in various research efforts, mainly by adding an auxiliary control loop to the control structure of the wind turbine. In most of the studies, this control loop is composed of linear blocks. In this paper, simple adaptive control is used for this purpose. In order to use an adaptive controller, the convergence of the controller should be verified. Since adaptive control parameters tend to optimum values in order to obtain optimum control performance, using this controller will help the wind turbines to have positive contribution in damping the network subsynchronous oscillations at different wind speeds and system operating points. In this paper, the application of simple adaptive control in DFIG wind turbine systems to improve the dynamic stability of power systems is studied and the essential condition for using this controller is considered. It is also shown that this controller has an insignificant effect on the dynamic stability of the wind turbine, itself.Keywords: almost strictly positive real (ASPR), doubly-fed induction generator (DIFG), simple adaptive control (SAC), subsynchronous oscillations, wind turbine
Procedia PDF Downloads 3685574 Modeling and Power Control of DFIG Used in Wind Energy System
Authors: Nadia Ben Si Ali, Nadia Benalia, Nora Zerzouri
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Wind energy generation has attracted great interests in recent years. Doubly Fed Induction Generator (DFIG) for wind turbines are largely deployed because variable-speed wind turbines have many advantages over fixed-speed generation such as increased energy capture, operation at maximum power point, improved efficiency, and power quality. This paper presents the operation and vector control of a Doubly-fed Induction Generator (DFIG) system where the stator is connected directly to a stiff grid and the rotor is connected to the grid through bidirectional back-to-back AC-DC-AC converter. The basic operational characteristics, mathematical model of the aerodynamic system and vector control technique which is used to obtain decoupled control of powers are investigated using the software Mathlab/Simulink.Keywords: wind turbine, Doubly Fed Induction Generator, wind speed controller, power system stability
Procedia PDF Downloads 3685573 Genetic Algorithm Optimization of a Small Scale Natural Gas Liquefaction Process
Authors: M. I. Abdelhamid, A. O. Ghallab, R. S. Ettouney, M. A. El-Rifai
Abstract:
An optimization scheme based on COM server is suggested for communication between Genetic Algorithm (GA) toolbox of MATLAB and Aspen HYSYS. The structure and details of the proposed framework are discussed. The power of the developed scheme is illustrated by its application to the optimization of a recently developed natural gas liquefaction process in which Aspen HYSYS was used for minimization of the power consumption by optimizing the values of five operating variables. In this work, optimization by coupling between the GA in MATLAB and Aspen HYSYS model of the same process using the same five decision variables enabled improvements in power consumption by 3.3%, when 77% of the natural gas feed is liquefied. Also on inclusion of the flow rates of both nitrogen and carbon dioxide refrigerants as two additional decision variables, the power consumption decreased by 6.5% for a 78% liquefaction of the natural gas feed.Keywords: stranded gas liquefaction, genetic algorithm, COM server, single nitrogen expansion, carbon dioxide pre-cooling
Procedia PDF Downloads 4355572 Design of CMOS CFOA Based on Pseudo Operational Transconductance Amplifier
Authors: Hassan Jassim Motlak
Abstract:
A novel design technique employing CMOS Current Feedback Operational Amplifier (CFOA) is presented. The feature of consumption whivh has a very low power in designing pseudo-OTA is used to decreasing the total power consumption of the proposed CFOA. This design approach applies pseudo-OTA as input stage cascaded with buffer stage. Moreover, the DC input offset voltage and harmonic distortion (HD) of the proposed CFOA are very low values compared with the conventional CMOS CFOA due to symmetrical input stage. P-Spice simulation results using 0.18µm MIETEC CMOS process parameters using supply voltage of ±1.2V and 50μA biasing current. The P-Spice simulation shows excellent improvement of the proposed CFOA over existing CMOS CFOA. Some of these performance parameters, for example, are DC gain of 62. dB, open-loop gain-bandwidth product of 108 MHz, slew rate (SR+) of +71.2V/µS, THD of -63dB and DC consumption power (PC) of 2mW.Keywords: pseudo-OTA used CMOS CFOA, low power CFOA, high-performance CFOA, novel CFOA
Procedia PDF Downloads 303