On the selection of parameters of cable lines 6 -10 kV in the calculations and simulation of transients with single-phase earth faults

The modeling and calculation of a single phase-to-earth fault of 6 to 35 kV have specific features when compared with circuits with higher nominal voltages. In this paper, a mathematical analysis and modeling of a 3-phase overhead transmission line with distributed parameters consisting of several nominal T-shaped, 3-phase links with concentrated parameters replaced by 1 nominal T-shaped link were carried out. Further analysis showed that not accounting for the distributed nature of the line parameters did not cause significant errors in the assessment of the maximum overvoltage in the arc suppression in single phase-to-earth faults, and that sufficient accuracy insures the representation of the line by only 1 nominal T-shaped, 3-phase link. Such a modeling technique makes it impossible to identify the location of single-phase faults, which is the property of higher harmonic amplification of individual frequencies. Chain equivalent schemas with constant parameters are valid for a single frequency, thereby providing an opportunity to study the nature of the wave process by the discrete selection of parameters. Next in the mathematical representation, we consider the overhead transmission lines as lines with distributed parameters.

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Voltages Induced in Overhead Ground-Wire Cable as Risk Factor. Part 1

Safety in Technosphere ◽

10.12737/19021 ◽

2016 ◽

Vol 5 (1) ◽

pp. 28-40 ◽

Cited By ~ 1

Author(s):

Токарский ◽

A. Tokarskiy ◽

Рубцова ◽

Nina Rubtsova ◽

Рябченко ◽

...

Keyword(s):

Risk Factor ◽

Single Phase ◽

Interval Length ◽

Maximum Permissible Level ◽

Overhead Transmission Line ◽

Spark Gap ◽

Three Phase ◽

Electric And Magnetic Fields ◽

Short Circuits ◽

Selection Of

To ensure the staff safety under hot-line overhead transmission line (OTL) maintenance, as well as overhead ground-wire cable (OGWC) insulation integrity maintaining, by the example of three-phase 750 kV OTL has been presented an algorithm for calculation of voltages and electromotive forces (EMF) induced in this line’s OGWC by electric and magnetic fields (EF and MF) generated by OTL phases’ voltages and currents. Algorithms for calculation of line-to-earth voltages distribution along grounded at one end OGWC’ intervals have been given. It has been shown that the voltage induced at OGWC by EF of 750 kV OTL is much less than the voltage induced by this OTL’s MF. For single-phase short circuits modes has been presented an algorithm for selection of grounded at one end OGWC’ interval length by condition of respecting of voltage’s maximum permissible level on a spark gap shunting OGWC’s insulator set.

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Non-Darcy effects in fracture flows of a yield stress fluid

Journal of Fluid Mechanics ◽

10.1017/jfm.2016.491 ◽

2016 ◽

Vol 805 ◽

pp. 222-261 ◽

Cited By ~ 24

Author(s):

A. Roustaei ◽

T. Chevalier ◽

L. Talon ◽

I. A. Frigaard

Keyword(s):

Pressure Gradient ◽

Yield Stress ◽

Single Phase ◽

Stokes Problem ◽

Type Flow ◽

New Type ◽

Approximate Expressions ◽

Limiting Pressure Gradient ◽

Selection Of ◽

Limiting Pressure

We study non-inertial flows of single-phase yield stress fluids along uneven/rough-walled channels, e.g. approximating a fracture, with two main objectives. First, we re-examine the usual approaches to providing a (nonlinear) Darcy-type flow law and show that significant errors arise due to self-selection of the flowing region/fouling of the walls. This is a new type of non-Darcy effect not previously explored in depth. Second, we study the details of flow as the limiting pressure gradient is approached, deriving approximate expressions for the limiting pressure gradient valid over a range of different geometries. Our approach is computational, solving the two-dimensional Stokes problem along the fracture, then upscaling. The computations also reveal interesting features of the flow for more complex fracture geometries, providing hints about how to extend Darcy-type approaches effectively.

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10kV Grid Arc Grounding Over-Voltage Hazards and Countermeasures

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.392.489 ◽

2013 ◽

Vol 392 ◽

pp. 489-493

Author(s):

Qing Hao Wang ◽

Zi Jun Huang ◽

Zhi Gang Li ◽

Bo Fang ◽

Gui Bin Hu

Keyword(s):

Single Phase ◽

Power Grid ◽

Operation Mode ◽

Scientific Basis ◽

Neutral Point ◽

Correct Selection ◽

Capacitive Current ◽

Current Test ◽

Selection Of

Through the analysis of 2 single-phase grounding over voltage accidents caused by capacitive over current in 10 kV power grid in this paper, the causes and damages of arc grounding over voltage are illustrated, and the necessity of capacitive current test and effective methods are pointed out. The test and assessment to the 29 substations capacitor currents provides a scientific basis for the correct selection of the neutral point operation mode, and the strengths and weaknesses of the neutral Point grounding through the arc suppression circle and the mode trends of 10kV grid neutral grounding are demonstrated.

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Microemulsion Performance Fluids

MRS Proceedings ◽

10.1557/proc-177-251 ◽

1989 ◽

Vol 177 ◽

Author(s):

J. Bock ◽

M. L. Robbins ◽

S. J. Pace

Keyword(s):

Phase Behavior ◽

Single Phase ◽

Interfacial Area ◽

Immiscible Fluids ◽

Proper Selection ◽

Solubilization Capacity ◽

Low Interfacial Tension ◽

Multi Phase ◽

The Relationship ◽

Selection Of

ABSTRACTMicroemulsions are thermodynamically stable mixtures of two immiscible fluids, such as oil and water, and one or more surfactants or cosurfactants. These systems have a rich micro-structure and phase behavior which can take the form of a variety of multi-phase and single phase oil- or watercontinuous or bicontinuous fluids with unique and useful properties. The thermodynamic stability, ultra-low interfacial tension, clarity, high solubilization capacity and high interfacial area suggest uses “performance fluids.” The relationship between surfactant ussetsru cfotur reth eansde the phase behavior and properties of microemulsions is the key to their design. Through the proper selection of surfactants, microemulsion phase continuity can be tailored for a variety of applications. Two such applications, coal freeze conditioning and oil spill dispersion, are described in this paper.

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Selection of magnetization curves for accurately simulating a three-phase self-excited induction generator feeding a single-phase load

2000 IEEE Power Engineering Society Winter Meeting. Conference Proceedings (Cat. No.00CH37077) ◽

10.1109/pesw.2000.849973 ◽

2002 ◽

Cited By ~ 4

Author(s):

Li Wang ◽

Chang-Min Cheng

Keyword(s):

Single Phase ◽

Induction Generator ◽

Magnetization Curves ◽

Three Phase ◽

Selection Of

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EXPERIMENTAL EVALUATION OF STEREOLOGICAL METHODS FOR DETERMINING 3D GRAIN SIZE AND TOPOLOGICAL DISTRIBUTIONS

Image Analysis & Stereology ◽

10.5566/ias.v19.p91-97 ◽

2011 ◽

Vol 19 (2) ◽

pp. 91 ◽

Cited By ~ 6

Author(s):

Guoquan Liu ◽

Haibo Yu

Keyword(s):

Grain Size ◽

Size Distribution ◽

Grain Size Distribution ◽

Experimental Evaluation ◽

Single Phase ◽

Experimental Methods ◽

Grain Structure ◽

Serial Sectioning ◽

Topological Parameters ◽

Selection Of

The conventional serial sectioning analysis and a set of modern stereological methods, including disector, selector, point-sampled intercepts, point-sampled area, and their combinations, have been used in this paper to measure the grain size, grain size distribution, topological parameters and their distributions in a spacefilling single-phase grain structure of steel. The results from different methods are compared and used to evaluate the methods quantitatively, based on which some suggestions will be given for selection of experimental methods in materials stereology research.

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Review Scope on Design & Operation of Automatic Power Factor Controller Circuit with Artificial Intelligence using Fuzzy Logic

International Journal for Research in Applied Science and Engineering Technology ◽

10.22214/ijraset.2021.37052 ◽

2021 ◽

Vol 9 (VII) ◽

pp. 3248-3256

Author(s):

Sandeep Bishla

Keyword(s):

Artificial Intelligence ◽

Fuzzy Logic ◽

Induction Motor ◽

Power Factor ◽

Single Phase ◽

Reactive Power ◽

Sleep Mode ◽

Capacitor Banks ◽

K Factor ◽

Selection Of

This paper shows the scope of making an automatic Power Factor controller with the help of Fuzzy Logic. A Single-phase PF circuit is taken for experimental purposes in two sets of capacitor banks. Single-phase supply connected to Induction Motor as load considering for power factor correction. Capacitor along with its circuit connected in parallel to the Induction Motor. Selection of capacitor is done based on multiplier table using K Factor along with initial Cos of the load. Incoming control from MCB and current measurement are done at incoming as well as on capacitor banks individually. Seeking best selection, represent the relation between KVAr and µF. Results show we got desired permutations & combinations of data for making the FLC rule table. By this, we also thought about the industrial application using reactive power during the jerking load and sleep mode of machines.

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