A network asset based probabilistic model of ground potential rise and touch voltage hazard profiles at MV substations

2016 ◽  
Author(s):  
Matthew B. Bastian ◽  
William D. Carman ◽  
Darren J. Woodhouse
Keyword(s):  
Probabilistic Model ◽  
Touch Voltage ◽  
Ground Potential

scholarly journals Effects of lightning impulse front time on substation grounding system performance

2020 ◽  
Vol 20 (2) ◽  
pp. 569
Author(s):  
Muhammad Adnan ◽  
Zulkurnain Adul Malek ◽  
Nur Syazwani Mohd Din ◽  
Muhammad Irfan Jambak ◽  
Zainuddin Nawawi ◽  
...  
Keyword(s):  
Short Circuit ◽  
Lightning Discharge ◽  
Soil Resistivity ◽  
Grounding System ◽  
Step Voltage ◽  
Different Types ◽  
Lightning Impulse ◽  
Touch Voltage ◽  
Ground Potential

<table width="593" border="1" cellspacing="0" cellpadding="0"><tbody><tr><td valign="top" width="387"><p>The role of the grounding system in the safety of the power system and protection of personnel is obvious during an unexpected short circuit or lightning discharge at the substation. The aim of this work is to analyze the effects of several parameters: lightning impulse front time, soil resistivity and types of grid materials on the grounding system of the Substation. The ground potential rise (GPR), touch voltage and step voltage of a 50 m x 60 m grounding grid buried at a depth of 0.5 m were computed using CDEGS when injected by impulse with different front times. Results show that the shorter the front time of lightning impulse waveform, the higher the value of GPR, touch voltage and step voltage. Meanwhile, when the value of soil resistivity is increased, the value of GPR, touch voltage and step voltage is also increased. Lastly, different types of grid conductor materials give different values of GPR, touch voltage and step voltage. However, it can be said that the differences are too small to be of any significance.</p><p> </p></td></tr></tbody></table>

Step and Touch Voltages and Grounding Potential Rise (IEEE and IEC)

2018 ◽  
pp. 187-247
Keyword(s):  
Reduction Factor ◽  
Scaling Factor ◽  
Three Dimensions ◽  
Voltage Profile ◽  
Soil Resistivity ◽  
Step Voltage ◽  
Grounding Grids ◽  
Ieee Standards ◽  
Touch Voltage ◽  
Ground Potential

This chapter contains safety criteria according to IEEE Standards, step and touch voltage criteria, reduction factor, simplified equations for mesh and step voltage, application of step and mesh potential in safe earthing system design, safety criteria, IEC 479-1 STD, permissible touch and step voltage according to IEC 479-1, Optimum Compression Ratio (OCR), test and verify, approximated analysis to calculate voltage profile using apparent soil resistivity, Scaling factor, test and verify the approximated method—Ground Potential Rise (GPR) of faulty substations having equal and unequal spacing grounding grids conductors. This chapter draws attention also to the following points: Infinite Series Potential (I.S.M.) expressions in three dimensions and calculations of three dimensions potential rise.

A New High Intensity Grid Cap for RCA-EMU-3 Electron Microscopes

1968 ◽  
Vol 26 ◽  
pp. 316-317
Author(s):  
George Christov ◽  
Bolivar J. Lloyd
Keyword(s):  
Electron Beam ◽  
Electron Microscope ◽  
High Voltage ◽  
High Intensity ◽  
Electron Gun ◽  
Tungsten Filament ◽  
Fluorescent Screen ◽  
Electron Microscopes ◽  
Pass Through ◽  
Ground Potential

A new high intensity grid cap has been designed for the RCA-EMU-3 electron microscope. Various parameters of the new grid cap were investigated to determine its characteristics. The increase in illumination produced provides ease of focusing on the fluorescent screen at magnifications from 1500 to 50,000 times using an accelerating voltage of 50 KV.The EMU-3 type electron gun assembly consists of a V-shaped tungsten filament for a cathode with a thin metal threaded cathode shield and an anode with a central aperture to permit the beam to course the length of the column. The cathode shield is negatively biased at a potential of several hundred volts with respect to the filament. The electron beam is formed by electrons emitted from the tip of the filament which pass through an aperture of 0.1 inch diameter in the cap and then it is accelerated by the negative high voltage through a 0.625 inch diameter aperture in the anode which is at ground potential.

Assessment and Analysis of Credit Risk with Using of Logical and Probabilistic Model

2002 ◽  
Author(s):  
Vassilij Karassev ◽  
Andrey Roukine ◽  
E.D. Dmitrievich Solojentsev
Keyword(s):  
Credit Risk ◽  
Probabilistic Model

scholarly journals Joint Semantic Synthesis and Morphological Analysis of the Derived Word

2018 ◽  
Vol 6 ◽  
pp. 33-48 ◽  
Author(s):  
Ryan Cotterell ◽  
Hinrich Schütze
Keyword(s):  
Neural Networks ◽  
Recurrent Neural Networks ◽  
Probabilistic Model ◽  
Morphological Analysis ◽  
Semantic Representation ◽  
English Word ◽  
Word Formation ◽  
Additive Models ◽  
Segmentation Accuracy ◽  
Morphological Productivity

Much like sentences are composed of words, words themselves are composed of smaller units. For example, the English word questionably can be analyzed as question+ able+ ly. However, this structural decomposition of the word does not directly give us a semantic representation of the word’s meaning. Since morphology obeys the principle of compositionality, the semantics of the word can be systematically derived from the meaning of its parts. In this work, we propose a novel probabilistic model of word formation that captures both the analysis of a word w into its constituent segments and the synthesis of the meaning of w from the meanings of those segments. Our model jointly learns to segment words into morphemes and compose distributional semantic vectors of those morphemes. We experiment with the model on English CELEX data and German DErivBase (Zeller et al., 2013) data. We show that jointly modeling semantics increases both segmentation accuracy and morpheme F1 by between 3% and 5%. Additionally, we investigate different models of vector composition, showing that recurrent neural networks yield an improvement over simple additive models. Finally, we study the degree to which the representations correspond to a linguist’s notion of morphological productivity.

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