scholarly journals Small-Scale Arc Fault Testing of Medium-Voltage Metal-Enclosed Switchgear

2016 ◽  
Vol 31 (1) ◽  
pp. 37-43 ◽  
Author(s):  
Elin Fjeld ◽  
Svein T. Hagen
Keyword(s):  
Small Scale ◽  
Fault Testing ◽  
Medium Voltage

scholarly journals Hour-Ahead Energy Trading Management with Demand Forecasting in Microgrid Considering Power Flow Constraints

Energies ◽  
2019 ◽  
Vol 12 (18) ◽  
pp. 3494
Author(s):  
Kuo Feng ◽  
Chunhua Liu ◽  
Zaixin Song
Keyword(s):  
Power Flow ◽  
Low Voltage ◽  
Supply And Demand ◽  
Demand Forecasting ◽  
Distribution Networks ◽  
Small Scale ◽  
Energy Trading ◽  
Medium Voltage ◽  
The Neural Network ◽  
Flow Constraints

Multiple small-scale low-voltage distribution networks with distributed generators can be connected in a radial pattern to form a multi-bus medium voltage microgrid. Additionally, each bus has an independent operator that can manage its power supply and demand. Since the microgrid operates in the market-oriented mode, the bus operators aim to maximize their own benefits and expect to protect their privacy. Accordingly, in this paper, a distributed hour-ahead energy trading management is proposed. First, the benefit optimization problem of the microgrid is solved, which is decomposed into the local benefit optimization sub problems of buses. Then, the local sub problems can be solved by the negotiation of operators with their neighbors. Additionally, the reference demand before negotiation is forecasted by the neural network rather than given in advance. Furthermore, the power flow constraints are considered to guarantee the operational stability. Meanwhile, the power loss minimization is considered in the objective function. Finally, the demonstration and simulation cases are given to validate the effectiveness of the proposed hour-ahead energy trading management.

scholarly journals Micro-Grid Design and Protection System under Several Fault Conditions

2019 ◽  
Vol 8 (6) ◽  
pp. 875-880
Keyword(s):  
Fault Analysis ◽  
Environmental Benefits ◽  
Protection System ◽  
Small Scale ◽  
Photovoltaic Module ◽  
Distributed Generator ◽  
Medium Voltage ◽  
Protection Scheme ◽  
Micro Grid ◽  
Design Protection

As distributed generators and renewable energies are now becoming the fastest growing technologies in the energy industries, the technical issues and environmental aspects are to studied and examined. The large number of small scale Micro grid components with their characteristics is a vital challenge for Micro grid modelling, operation, simulation and operation. Micro-grid gives clear, economic and environmental benefits for end users, utilities, and societies. However, their implementation faces lot of challenges, such as a protection of micro-grid. Micro-grid works in two modes, grid-connected and islanded mode that operates connected with medium voltage grid or islanded from the grid with controlled coordinate manner. The major goal of this thesis is to design protection for. First, the work is done to present the detailed description of the micro grid models and lines. Then the paper will discuss the distributed generator models that have been implemented in MATLAB/Simulink including photovoltaic module, fuel cell stack system with short term storage (Li-ion battery system). Then the fault analysis is done for the whole Micro-grid, whether the micro grid is working in fault condition or not. Then Micro grid protection is done for the grid connected modes and islanding modes of Micro grid. To design the protection system for the micro grid over current relay protection scheme is used.

scholarly journals Mengembangkan Potensi Energi Terbarukan Di Jaringan Irigasi Dengan Pembangkit Listrik Tenaga Mikro Hidro (Pltmh)

2012 ◽  
Vol 9 (1) ◽  
Author(s):  
Suwignyo .
Keyword(s):  
Renewable Energy ◽  
Renewable Energy Sources ◽  
Mineral Resources ◽  
Energy Sources ◽  
Small Scale ◽  
Hydro Development ◽  
Hydro Power ◽  
Irrigation Network ◽  
Medium Voltage ◽  
Irrigation Networks

Power Generation Potential Micro Hydro Mini & Micto Hydro (PLTM & PLTMH) in Indonesia reached 0.45 GWatt, has been developed for 0084 GWatt (18%). One potential PLTM & PLTMH is irrigation networks, both new irrigation networks and existing irrigation networks.  Wide of  †rice fields in Indonesia are 6134 million ha, consisting of 19,344 technical irrigation network mainly scattered in the island of Java, Sumatra, Sulawesi, Bali and West Nusa Tenggara Province. Year 2005 has been successfully built the capacity of 100 kW PLTMH Melong exploit irrigation networks were involved networks fall building in Curug Agung in Subang district.  PLTMH produced 700,800 KWh of energy per year, medium voltage network interconnected with PLN.  In April 2008 this power of Micro Hydro Power (PLTMH) with a capacity of 100 kW operating in Campus University Muhammadiyah of  Malang (UMM) and this is collaboration result of UMM with the National Research and Development ( Balitbang) Ministry of Energy and Mineral Resources of Indonesia.  UMM PLTMH Development is to promote the use of renewable energy sources as part of efforts to overcome the energy crisis as well as efforts to decrease greenhouse gas emissions that cause global warming. One type of renewable energy sources are small -scale water or micro- hydro.  Development of PLTM & PLTMH in irrigation networks can be done in the main building, building falls, and buildings structures to complement that have a high hydraulic fall.  The study on an irrigation network D.I. in Kedungkandang Malang shows that the potential power in buildings comes up in irrigation on the main channel reaches about 1 MWatt.Key words: power, micro hydro, irrigation channels

Reasons to strike first

2019 ◽  
Vol 42 ◽  
Author(s):  
William Buckner ◽  
Luke Glowacki
Keyword(s):  
Intergroup Conflict ◽  
Small Scale

Abstract De Dreu and Gross predict that attackers will have more difficulty winning conflicts than defenders. As their analysis is presumed to capture the dynamics of decentralized conflict, we consider how their framework compares with ethnographic evidence from small-scale societies, as well as chimpanzee patterns of intergroup conflict. In these contexts, attackers have significantly more success in conflict than predicted by De Dreu and Gross's model. We discuss the possible reasons for this disparity.

Exploring Coronal Structures with SOHO

2000 ◽  
Vol 179 ◽  
pp. 403-406
Author(s):  
M. Karovska ◽  
B. Wood ◽  
J. Chen ◽  
J. Cook ◽  
R. Howard
Keyword(s):  
Solar Corona ◽  
Image Enhancement ◽  
Coronal Mass Ejections ◽  
Dynamical Evolution ◽  
Small Scale ◽  
Low Contrast ◽  
Contrast Structures ◽  
Scale Structures ◽  
Small Scale Structures ◽  
Coronal Structures

AbstractWe applied advanced image enhancement techniques to explore in detail the characteristics of the small-scale structures and/or the low contrast structures in several Coronal Mass Ejections (CMEs) observed by SOHO. We highlight here the results from our studies of the morphology and dynamical evolution of CME structures in the solar corona using two instruments on board SOHO: LASCO and EIT.

Prospects for convergent beam electron diffraction with a 200kV cold field-emission transmission electron microscope

1991 ◽  
Vol 49 ◽  
pp. 466-467
Author(s):  
J W Steeds ◽  
R Vincent
Keyword(s):  
Field Emission ◽  
High Performance ◽  
Small Diameter ◽  
Convergent Beam Electron Diffraction ◽  
Zone Axis ◽  
Medium Voltage ◽  
Transmission Electron ◽  
Good Crystallinity ◽  
Special Modification ◽  
Convergent Beam

We review the analytical powers which will become more widely available as medium voltage (200-300kV) TEMs with facilities for CBED on a nanometre scale come onto the market. Of course, high performance cold field emission STEMs have now been in operation for about twenty years, but it is only in relatively few laboratories that special modification has permitted the performance of CBED experiments. Most notable amongst these pioneering projects is the work in Arizona by Cowley and Spence and, more recently, that in Cambridge by Rodenburg and McMullan.There are a large number of potential advantages of a high intensity, small diameter, focussed probe. We discuss first the advantages for probes larger than the projected unit cell of the crystal under investigation. In this situation we are able to perform CBED on local regions of good crystallinity. Zone axis patterns often contain information which is very sensitive to thickness changes as small as 5nm. In conventional CBED, with a lOnm source, it is very likely that the information will be degraded by thickness averaging within the illuminated area.

Atomic structure imaging of the Si/SiO2 interface with high-resolution electron microscopy

1986 ◽  
Vol 44 ◽  
pp. 390-391
Author(s):  
J.L. Batstone ◽  
J.M. Gibson ◽  
Alice.E. White ◽  
K.T. Short
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Atomic Structure ◽  
High Resolution Electron Microscopy ◽  
Medium Voltage ◽  
Voltage Electron ◽  
Resolution Electron ◽  
Structural Image ◽  
Electron Microscopes ◽  
Point To Point

High resolution electron microscopy (HREM) is a powerful tool for the determination of interface atomic structure. With the previous generation of HREM's of point-to-point resolution (rpp) >2.5Å, imaging of semiconductors in only <110> directions was possible. Useful imaging of other important zone axes became available with the advent of high voltage, high resolution microscopes with rpp <1.8Å, leading to a study of the NiSi2 interface. More recently, it was shown that images in <100>, <111> and <112> directions are easily obtainable from Si in the new medium voltage electron microscopes. We report here the examination of the important Si/Si02 interface with the use of a JEOL 4000EX HREM with rpp <1.8Å, in a <100> orientation. This represents a true structural image of this interface.

Scanning tunneling microscopy and atomic force microscopy: New tools for biology

1989 ◽  
Vol 47 ◽  
pp. 778-779
Author(s):  
CE Bracker ◽  
P. K. Hansma
Keyword(s):  
Physical Property ◽  
Scanning Probe ◽  
Scanning Tunneling ◽  
Small Scale ◽  
Tunneling Microscopy ◽  
Force Microscopy ◽  
New Family ◽  
Small Probe ◽  
Atomic Force ◽  
Transmission Electron

A new family of scanning probe microscopes has emerged that is opening new horizons for investigating the fine structure of matter. The earliest and best known of these instruments is the scanning tunneling microscope (STM). First published in 1982, the STM earned the 1986 Nobel Prize in Physics for two of its inventors, G. Binnig and H. Rohrer. They shared the prize with E. Ruska for his work that had led to the development of the transmission electron microscope half a century earlier. It seems appropriate that the award embodied this particular blend of the old and the new because it demonstrated to the world a long overdue respect for the enormous contributions electron microscopy has made to the understanding of matter, and at the same time it signalled the dawn of a new age in microscopy. What we are seeing is a revolution in microscopy and a redefinition of the concept of a microscope.Several kinds of scanning probe microscopes now exist, and the number is increasing. What they share in common is a small probe that is scanned over the surface of a specimen and measures a physical property on a very small scale, at or near the surface. Scanning probes can measure temperature, magnetic fields, tunneling currents, voltage, force, and ion currents, among others.

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