scholarly journals Research for Forming up the Controlling Diagram Utilizing the Connection of a LV Resistor on Voltage Transformer’s Open-Triagle Coil to Reduce over Voltage Caused by Earth Fault in 6 kV Grid of QuangNinh Underground Mines

2018 ◽  
Vol 35 ◽  
pp. 05001
Author(s):  
Ho Viet Bun ◽  
Le Xuan Thanh
Keyword(s):  
Single Phase ◽  
Underground Mines ◽  
Human Being ◽  
Relay System ◽  
Technical Parameters ◽  
Earth Fault ◽  
Electric Equipment ◽  
Open Triangle ◽  
Simulation Results

Single phase earth-fault in MV grids usually causes overvoltage that harm to human being and electric equipment. If the magnitude of over voltage is so great, many grids’ eco-technical parameters will be affected. The paper analyzes all possible consequences of over voltage occurred in 6 kV grid of QuangNinh underground mines. Base on the analysis, a controlling diagram utilizing the connection of a LV resistor on voltage transformer’s open-triangle coil to reduce over voltage is recommended. The simulation results of the diagram are used to prove the effectiveness of solution: the over voltage magnitude is only in the range of (2,1–2,4).Uf. Other advantage that solution brings to relay system will be pointed out.

Transmission line fault location for single-phase-to-earth fault on non-direct-ground neutral system

1998 ◽  
Vol 13 (4) ◽  
pp. 1086-1092 ◽  
Author(s):  
Zhang Qingchao ◽  
Zhang Yao ◽  
Song Wennan ◽  
Fang Dazhong
Keyword(s):  
Transmission Line ◽  
Fault Location ◽  
Single Phase ◽  
Neutral System ◽  
Earth Fault

Simulation of Intrinsic Diffusion in Multicomponent Multiphase Systems

1998 ◽  
Vol 527 ◽  
Author(s):  
M. Hunkel ◽  
D. Bergner
Keyword(s):  
Single Phase ◽  
Diffusion Flux ◽  
Wind Effect ◽  
Concentration Profiles ◽  
Intrinsic Diffusion ◽  
Cross Terms ◽  
Multiphase Systems ◽  
Random Alloy ◽  
Simulation Results ◽  
Vacancy Flux

ABSTRACTA simulation model for intrinsic diffusion of multicomponent multiphase systems is presented. The model is not restricted onto a certain number of components or phases. For simplicity, Manning's random alloy model with vanishing vacancy wind effect is used. Then the cross terms of the diffusion flux can be neglected. The simulation routine uses equations for the fluxes, the equation of continuity and an equation for the change of the thickness of volume elements due to the vacancy flux. With this model diffusions paths, concentration profiles, fluxes of the components as well as marker positions can be calculated. The shift of interfaces and the growth of new phases can also be determined. The simulation results were compared with experimental data of the Cu-Fe-Ni system. Diffusion was studied in single-phase areas and across interfaces.

scholarly journals Modeling Features of a Single Phase-to-Earth Fault in a Medium Voltage Overhead Transmission Line

2020 ◽  
Vol 4 (2) ◽  
pp. 127-138
Author(s):  
Ismael Saeed ◽  
Kamal Sheikhyounis
Keyword(s):  
Transmission Line ◽  
Transmission Lines ◽  
Single Phase ◽  
Single Frequency ◽  
Mathematical Representation ◽  
Medium Voltage ◽  
Overhead Transmission Line ◽  
Earth Fault ◽  
Distributed Parameters ◽  
Selection Of

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.

Recognition of Weak Harmonic Signal Components in Generator Protection Against Single-Phase Earth Fault

2018 ◽  
Vol 52 (2) ◽  
pp. 231-234 ◽  
Author(s):  
V. I. Antonov ◽  
V. A. Naumov ◽  
A. V. Soldatov ◽  
N. G. Ivanov ◽  
D. A. Mitin
Keyword(s):  
Single Phase ◽  
Harmonic Signal ◽  
Generator Protection ◽  
Earth Fault

Proposal of unmanned ground vehicle powered by fuel cell

2021 ◽  
Vol 16 (1) ◽  
pp. 5-13
Author(s):  
Vladimír Popardovský ◽  
◽  
Peter Bondra ◽  
Lukáš Novotný ◽  
◽  
...  
Keyword(s):  
Fuel Cell ◽  
Electric Drive ◽  
Graphical Form ◽  
Unmanned Ground Vehicle ◽  
Simulation Environment ◽  
Ground Vehicle ◽  
Technical Parameters ◽  
Simulation Results ◽  
Physical Quantities ◽  
Over Time

The presented article deals with the design of an unmanned ground vehicle (UGV) with electric drive, using a fuel cell as a source of electricity. The introduction describes the principle of the fuel cell, followed by the design of the UGV propulsion system. The UGV design, taking into account specific technical parameters, is processed into a model in the simulation environment MATLAB / Simulink / Simscape. Simulation results are presented in graphical form of selected physical quantities over time.

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