Fault Protection Considerations For Mvdc Shipboard Power Systems Operating With Pulsed-Power Loads,
2021
Old Dominion University
Fault Protection Considerations For Mvdc Shipboard Power Systems Operating With Pulsed-Power Loads, Marounfa Djibo, Paul Moses, Ike Flory
Electrical & Computer Engineering Faculty Publications
Medium Voltage Direct Current (MVDC) power distribution architectures are of immense interest for various shipboard power applications due to their advantages over classical MVAC distribution systems with respect to power quality, power density, and efficiency. However, MVDC are far away from maturity when compared to MVAC with respect to fault detection and isolation. Currently, there are no standards available for applying MVDC protection systems in shipboard applications. Furthermore, due to the absence of zero crossings in DC waveforms and unique transient fault signatures, it is challenging to design effective protection system schemes to isolate faults via conventional protection systems. This …
Real Time Adaptive Relay Settings For Microgrid Protection Verified Using Hardware In Loop,
2021
Michigan Technological University
Real Time Adaptive Relay Settings For Microgrid Protection Verified Using Hardware In Loop, Aadam Harnekar
Dissertations, Master's Theses and Master's Reports
Microgrids with penetration of renewables is imposing new challenges for system protection. Renewables are characterized with high source impedance which limit the short circuit current. The value of short-circuit current is limited due to converters used which limit the current to a maximum of 1.1 to 1.5 times maximum rated load current. This can result in faults during the islanded mode of microgrid to go unnoticed if the relay settings are not adapted to account for it. The presence of such uncleared faults in the microgrid can result in exposing it to overcurrent for a long time which can damage …
Reverse Engineering Of Short Circuit Analyses,
2021
Michigan Technological University
Reverse Engineering Of Short Circuit Analyses, Anurag Nagpure
Dissertations, Master's Theses and Master's Reports
The electrical distribution system has evolved with embedded computer systems that can better manage the electrical fault that occurred around the feeders. Such random events can affect the reliability indices of overall systems. Computerized management system for distribution operation has been improving with the advanced sensing technologies. The general research question is here to articulate is the responsiveness for utility crew to pinpoint the exact location of a fault based on the SCADA fault indicators from pole-mounted feeder remote terminal units (FRTUs). This has been a tricky question because it relies on the information received from the sensors that can …
Quantifying The Value Of Foam-Based Flexible Floating Solar Photovoltaic Systems,
2021
Michigan Technological University
Quantifying The Value Of Foam-Based Flexible Floating Solar Photovoltaic Systems, Koami Soulemane Hayibo
Dissertations, Master's Theses and Master's Reports
Distributed generation with solar photovoltaic (PV) technology is economically competitive if net metered in the U.S. Yet there is evidence that net metering is misrepresenting the true value of distributed solar generation so that the value of solar (VOS) is becoming the preferred method for evaluating economics of grid-tied PV. VOS calculations are challenging and there is widespread disagreement in the literature on the methods and data needed. To overcome these limitations, this thesis reviews past VOS studies to develop a generalized model that considers realistic future avoided costs and liabilities. The approach used here is bottom-up modeling where the …
A Transdisciplinary Analysis Of Just Transition Pathways To 100% Renewable Electricity,
2021
Michigan Technological University
A Transdisciplinary Analysis Of Just Transition Pathways To 100% Renewable Electricity, Adewale Aremu Adesanya
Dissertations, Master's Theses and Master's Reports
The transition to using clean, affordable, and reliable electrical energy is critical for enhancing human opportunities and capabilities. In the United States, many states and localities are engaging in this transition despite the lack of ambitious federal policy support. This research builds on the theoretical framework of the multilevel perspective (MLP) of sociotechnical transitions as well as the concept of energy justice to investigate potential pathways to 100 percent renewable energy (RE) for electricity provision in the U.S. This research seeks to answer the question: what are the technical, policy, and perceptual pathways, barriers, and opportunities for just transition to …
Possibilities And Challenges Of Radio Frequency Energy Harvesting In Dar Es Salaam, Tanzania,
2020
Department of Electronics & Telecommunications Engineering, University of Dar es Salaam
Possibilities And Challenges Of Radio Frequency Energy Harvesting In Dar Es Salaam, Tanzania, Fredrick Isingo
Tanzania Journal of Engineering and Technology (TJET)
This paper presents investigation on the possibilities and challenges of harvesting ambient Radio Frequency Energy (RFE) at Dar es Salaam region in Tanzania. The Radio Frequency (RF) signals were measured using a Rohde and Schwarz FSC 3 spectrum analyzer observing available frequencies with their respective power. Among several RF signals received, the most powerful signals observed were; 800 MHz, 950 MHz, 2100 MHz and 2400 MHz, having average signal strengths of about-30.29 dBm,-35.94 dBm,-42.90 dBm and-30.42 dBm respectively. The power possessed within these frequencies were suitable to be harvested due to their signal strengths, an overall power average of-34.89dBm was …
User-Centred Scalable Big Data Visualizer For Power Consumption Data In The Electrical Secondary Distribution Network,
2020
Department of Computer Science and Engineering, University of Dar es Salaam
User-Centred Scalable Big Data Visualizer For Power Consumption Data In The Electrical Secondary Distribution Network, Ellen Kalinga
Tanzania Journal of Engineering and Technology (TJET)
Establishment of Smart Grids for electrical power has been practised worldwide for the purpose of bringing reliability, security, and efficient management of electrical power networks for enhancing quality service to the society. Apart from the potential aim, smart grid has been a challenge to developing countries, including Tanzania from cost and technology point of view. Due to the use of many smart equipment involved in smart grids like Advanced Metering Infrastructure (AMI) equipped with smart meters and sensors, handling and managing big data has been a challenge. Among the challenges is the issue of visualizing the Big Data due to …
Deconvolution Of Mono-Energetic And Multi-Lines Gamma-Ray Spectra Obtained With Nai(Tl) Scintillation Detectors Using Direct Matrix Inversion Method,
2020
University of Dar es salaam
Deconvolution Of Mono-Energetic And Multi-Lines Gamma-Ray Spectra Obtained With Nai(Tl) Scintillation Detectors Using Direct Matrix Inversion Method, Mwingereza John Kumwenda Dr
Tanzania Journal of Engineering and Technology (TJET)
Performance of a NaI(Tl) scintillation detector based on the gamma-ray spectroscopy system is not satisfactory in retaining its original peak (which is delta like function) of various gamma ray spectrum. The method of achieving precise peak for the various gamma ray was conducted by converting the observed pulse-height distribution of the NaI(Tl) detector to a true photon spectrum. This method is obtained experimentally with the help of an inverse matrix deconvolution method. The method is based on response matrix generated by the Monte Carlo simulation based on Geant4 package of mono-energy gamma-ray photon ranging from 0.050 to 2.04 MeV in …
Assessment Of The Performance Of Grinding Circuit For Buzwagi Gold Mine,
2020
University of Dar es Salaam, School of Mines and Geosciences, Department of Mining and Mineral Processing Engineering, P.O. Box 35131, Dar es Salaam, Tanzania
Assessment Of The Performance Of Grinding Circuit For Buzwagi Gold Mine, Alphonce Wikedzi
Tanzania Journal of Engineering and Technology (TJET)
It had been reported by the management of Buzwagi Gold Mine (BGM) that grinding circuit was designed to produce final product size of 125 μm, which had not been achieved for a long period of time under both, low to normal (i.e. 450-600 t/h) and high (i.e. > 650 t/h) throughputs. Also, the performance behaviour of the circuit had not been reviewed after long time of operation. Hence, an evaluation study was conducted in order to recommend improvement in mine operations. The study was realized through three circuit survey campaigns and laboratory experimentations. From the surveys, size distributions and solids contents …
Fermentability Of Concentrated Sulfuric Acid Hydrolyzates From Aspenwood And Pinewood,
2020
Department of Chemical and Mining Engineering, University of Dar es Salaam
Fermentability Of Concentrated Sulfuric Acid Hydrolyzates From Aspenwood And Pinewood, Kando Janga
Tanzania Journal of Engineering and Technology (TJET)
The fermentability of hydrolyzates derived from two-stage concentrated sulfuric acid hydrolysis of Trembling aspen (Populus tremula) and Scots pine (Pinus sylvestris) were investigated. Three types of hydrolyzates were produced at mild, moderate and high decrystallization severity conditions. Portions of each of the original hydrolyzates were concentrated by vacuum evaporation to increase the sugar fraction to simulate industrial applications. Both sets of hydrolyzates were fermented anaerobically using Saccharomyces cerevisiae ATCC 96581. After 23 hours of fermentation, complete glucose consumption was observed for all the original hydrolyzates, with no signs of inhibition. The ethanol yields from these hydrolyzates ranged from 68% to …
Analysis Of Performance Characteristics Predicted From Several Experimental Data And Conversion Methods For Pumps As Turbine Application Using Statistical Techniques,
2020
Department of Energy and Petroleum Engineering, University of Dodoma, P. O. Box 259, Dodoma, Tanzania.
Analysis Of Performance Characteristics Predicted From Several Experimental Data And Conversion Methods For Pumps As Turbine Application Using Statistical Techniques, Ombeni J. Mdee
Tanzania Journal of Engineering and Technology (TJET)
Different performance characteristics have been indicated when running centrifugal pumps in the reverse direction. The water flows from the discharge side of the pump to the suction side to run in the reverse direction and generate the mechanical rotational energy for the micro-hydropower plant. The current study evaluates the extent of variation of performance characteristics predicted by several experimental data from different pump-specific speeds and conversion methods. The performance characteristics discussed include the head, flow rate, efficiency and specific speed. The flow rate and head of a pump operating in pump mode divided with the characteristic of the pump operating …
Bibliometric Review Of Mppt Algorithms For Wind Energy Conversion Systems,
2020
Symbiosis Institute of Technology,Symbiosis International Deemed University, Pune, India
Bibliometric Review Of Mppt Algorithms For Wind Energy Conversion Systems, Jayshree Ashok Pande, Paresh Nasikkar
Library Philosophy and Practice (e-journal)
The existing conventional fuels are going up in prices and going down in availability. This has boosted the demand for renewable resources like wind energy. Wind energy being abundantly available is becoming very popular as it is a freely available pollution-free green energy. Some technical aspects like the tracking of maximum power from the wind energy conversion systems have a very high impact on the efficiency of the wind energy conversion systems. Several algorithms have been implemented for tracking the maximum power point of the wind energy conversion systems. The main objective of this paper is to study the extent …
Numerical Simulations Of Current And Temperature Distribution Of Symmetrical Double-Cathode Solid Oxide Fuel Cell Stacks Based On The Theory Of Electric-Chemical-Thermal Coupling,
2020
1. Faculty of Civil Engineering and Mechanics, Jiangsu University, Zhenjiang 212013, China;2. Ningbo Institute of Material Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China;
Numerical Simulations Of Current And Temperature Distribution Of Symmetrical Double-Cathode Solid Oxide Fuel Cell Stacks Based On The Theory Of Electric-Chemical-Thermal Coupling, Cheng-Rong Yu, Jian-Guo Zhu, Cong-Ying Jiang, Yu-Chen Gu, Ye-Xin Zhou, Zhuo-Bin Li, Rong-Min Wu, Zheng Zhong, Wan-Bing Guan
Journal of Electrochemistry
Solid oxide fuel cell (SOFC) is a high-efficient clean conversion device for future energy management. Because of the low antioxidant reduction ability and complex thermal stress, the structure of traditional asymmetrical thin anode-supported planar SOFC is easily to be broken under stack operating conditions. To overcome these defects, a new complete symmetrical SOFC based on double-sided cathodes was developed. To study the influences of gas flow direction and current collection mode on the cell performance inside stack, a numerical model was established by finite element method based on the theory of electro-thermo-chemo multiphysical coupling. By applying this model, the molar …
Degradation And Thermal Characteristics Of Lini0.8Co0.15Al0.05O2/Graphite Lithium Ion Battery After Different State Of Charge Ranges Cycling,
2020
1. Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, CAS Key Laboratory of Renewable Energy, Guangdong Provincial Key Laboratory of New and Renewable Energy Research and Development, Guangzhou 510640, China;
Degradation And Thermal Characteristics Of Lini0.8Co0.15Al0.05O2/Graphite Lithium Ion Battery After Different State Of Charge Ranges Cycling, Cun Wang, Wei-Jiang Zhang, Teng-Fei He, Bo Lei, You-Jie Shi, Yao-Dong Zheng, Wei-Lin Luo, Fang-Ming Jiang
Journal of Electrochemistry
The LiNi0.8Co0.15Al0.05O2 (NCA) cathode exhibits high energy density and large reversible capacity, which plays an essential role in the field of electric vehicles (EVs). However, low capacity retention and poor thermal stability limit its application. Few literatures are found for the capacity degradation mechanism of NCA/graphite batteries at home and abroad. The different state of charge (SOC) ranges cycle degradation behaviors of 18650-type NCA/graphite (2.4 Ah) battery were studied in this paper. The SOC ranges considered were 0% ~ 20% (low), 20% ~ 70% (medium), 70% ~ 100% (high), and 0% ~ 100% …
Preparations And Photoelectrochemical Performances Of Rgo-Tio2 Nanotubes Arrays,
2020
1. State Key Laboratory of Physical Chemistry of Solid Surfaces, Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, Fujian, China;
Preparations And Photoelectrochemical Performances Of Rgo-Tio2 Nanotubes Arrays, Ze-Yang Zhang, Lan Sun, Chang-Jian Lin
Journal of Electrochemistry
Decorating TiO2 nanotube arrays with RGO to improve the photocatalytic activity of TiO2 nanotube arrays has been reported. For the reported RGO-TiO2 nanotube arrays, TiO2 nanotube arrays were prepared by anodizing the high-purity Ti foil in an organic electrolyte for multiple-step treatments, while RGO were deposited on TiO2 nanotube arrays by using cyclic voltammetry or other electrical reduction methods. To enhance the reduction degree and the coverage of RGO on the resultant RGO-TiO2 nanotube arrays, in this work, the one-step electrochemical anodization in hydrofluoric acid was used to fabricate TiO2 nanotube arrays with …
Preparation And Process Optimization Of Cathode Materials For Lithium-Sulfur Batteries,
2020
Ningde Contemporary Amperex Technology Co., Ltd, Ningde Fujian 352106, China;
Preparation And Process Optimization Of Cathode Materials For Lithium-Sulfur Batteries, Kai Wu
Journal of Electrochemistry
Lithium-sulfur (Li-S) batteries represent promising candidates for next-generation energy storage system due to their high energy density and low material cost. However, the industrial application of Li-S batteries remains challenges because of the shuttle effect from lithium polysulfides and the lack of facial routes for Li-S battery preparation. To solve these problems, a cathode consisting of different commercial carbon materials, namely, acetylene black (SP), Ketjen Black (KB) and carbon nanotube (CNT), with sulfur (S) is prepared separately for Li-S battery. After the process of 8-h ball milling for KB/S composite, together with the polyvinyl pyrrolidone (PVP) binder, the cathode could …
Preparations And Sodium Storage Properties Of Ni3S2@Cnt Composite,
2020
School of Materials Science and Engineering, Lanzhou University of Technology, Lanzhou 730050;
Preparations And Sodium Storage Properties Of Ni3S2@Cnt Composite, Ming-Tao Duan, Yan-Shuang Meng, Hong-Shuai Zhang
Journal of Electrochemistry
Transition metal sulfides (TMSs)-based electrode materials with highly reversible sodium storage have attracted extensive attentions as one of the most prospective electrode materials for sodium ion batteries (SIBs). However, low cycling stability and rate property caused by large volume expansion and poor electronic conductivity during the electrochemical reaction still hamper their further practical application. In this work, in-situ encapsulated Ni3S2 nanoparticles in carbon nanotubes (Ni3S2@CNT) have been successfully fabricated as an anode material for high-performance SIBs by a one-step solid-phase calcination process. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), …
Effect Of Stereotaxically-Constructed Graphene On The Negative Electrode Performance Of Lead-Acid Batteries,
2020
Collaborative Innovation Center of Sustainable Energy Materials, Guangxi University,Nanning 530004, Guangxi, China;
Effect Of Stereotaxically-Constructed Graphene On The Negative Electrode Performance Of Lead-Acid Batteries, Pin-Song Chen, Yi-Tao Hu, Xin-Yi Zhang, Pei-Kang Shen
Journal of Electrochemistry
With the advantages of high ratio surface area, excellent conductivity and high stability, the stereotaxically-constructed graphene (SCG) material was added to the negative active material (NAM) of lead-acid battery for improving battery performance. XRD, SEM and cyclic voltammetry tests were carried out to analyze the influence of SCG on negative active material. It is found that the conversion efficiency of lead sulfate to lead in the negative active material added with SCG material was higher than that of control group, and the particle size of the lead sulfate obtained after the discharge reaction was smaller, which are favorable factors for …
Core-Shell Structured Ru@Ptru Nanoflower Electrocatalysts Toward Alkaline Hydrogen Evolution Reaction,
2020
State Key Laboratory of Fine Chemicals, School of Chemical Engineering,Dalian University of Technology, Dalian 116024, Liaoning, China;
Core-Shell Structured Ru@Ptru Nanoflower Electrocatalysts Toward Alkaline Hydrogen Evolution Reaction, Xue-Liang Wang, Yuan-Yuan Cong, Chen-Xi Qiu, Sheng-Jie Wang, Jia-Qi Qin, Yu-Jiang Song
Journal of Electrochemistry
Water electrolysis for hydrogen production is beneficial for solving the problem of energy crisis and environmental issues. It is necessary to study highly active and cost-effective catalysts toward hydrogen evolution reaction (HER) to reduce the consumption of noble metals. Herein, we report the synthesis of core-shell structured Ru@Pt0.24Ru nanoflowers electrocatalyst by stepwise reduction of Ru and Pt precursors in the mixture of oleylamine and benzyl alcohol at 160 oC. The average diameter of the resultant Ru@Pt0.24Ru was 16.5±4.0 nm with a bulk atomic ratio between Pt and Ru of 0.24:1 and a surface ratio of …
Effect Of Reaction Conditions On Cu⁃Catalyzed Co2 Electroreduction,
2020
1. CAS Key Laboratory of Low-carbon Conversion Science and Engineering, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai, 201210, China;2. University of Chinese Academy of Sciences, Beijing, 100049, China;
Effect Of Reaction Conditions On Cu⁃Catalyzed Co2 Electroreduction, Chang Zhu, Wei Chen, Yan-Fang Song, Xiao Dong, Gui-Hua Li, Wei Wei, Yu-Han Sun
Journal of Electrochemistry
Electrochemical conversion of carbon dioxide (CO2) driven by renewable electricity that can meet both carbon emission reduction and renewable energy utilization has been rapidly developed in recent years. Copper (Cu) catalyst has long been a promising candidate for CO2 electroreduction applications because of its natural abundance and specific capability of producing a substantial amount of C2 products. However, various metallic Cu electrodes reported have been significantly influenced by the adsorption of certain cation/anion ions, resulting in wide-span catalytic activities and selectivity for various products. In addition, a recent report demonstrated that by virtue of gas-diffusion flow cell …
