Transient modeling of transmission lines components with respect to corona phenomenon and grounding system to reduce the transient voltages caused by lightning Impulse

2015 ◽  
Author(s):  
Ebadollah Amouzad Mahdiraji ◽  
Nabiollah Ramezani
Keyword(s):  
Transmission Lines ◽  
Grounding System ◽  
Transient Modeling ◽  
Lightning Impulse ◽  
Transient Voltages

Neural Network Model to Estimate Resistivity of Ground Enhancers Reinforced with Graphene Nano Particles for Transmission Lines

2019 ◽  
Vol 58 ◽  
pp. 139-150
Author(s):  
Isaias Ramirez-Vazquez ◽  
Miguel Ramirez-Gonzalez ◽  
J. Eduardo Salgado-Talavera
Keyword(s):  
Neural Network ◽  
Network Model ◽  
Neural Network Model ◽  
Transmission Lines ◽  
Nano Particles ◽  
Grounding System ◽  
Surge Arresters ◽  
Lightning Impulse ◽  
Graphene Nanoparticles ◽  
Impulse Current

For many high voltage transmission lines, lightning is the first cause of outages. Different alternatives have been used to diminish these outages, like the use of counterpoise wires, installation of surge arresters, and the improvement of the grounding system using ground enhancers or chemical enhancers. In this paper, graphene nanoparticles were used to reformulate commercial ground enhancers. The results of this research end up in an improvement factor of up to 100 times the reduction in resistivity, when graphene nanoparticles are used. After lightning current impulse tests done on both types of samples, the performance of the un-reformulated ground enhancer samples shows a faster deterioration than the graphene reinforced ground enhancer samples. In order to establish a criterion to quantitatively rank the chemical ground enhancers ́ performance after the lightning impulse current tests, a neural network model was developed.

scholarly journals Lightning Performance Evaluation of Italian 150 kV Sub-Transmission Lines

Energies ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2142
Author(s):  
Fabio Massimo Gatta ◽  
Alberto Geri ◽  
Stefano Lauria ◽  
Marco Maccioni ◽  
Francesco Palone
Keyword(s):  
Monte Carlo ◽  
Performance Evaluation ◽  
Transmission Lines ◽  
Computational Cost ◽  
Lightning Strikes ◽  
Grounding System ◽  
Monte Carlo Procedure ◽  
Overhead Transmission Lines ◽  
Realistic Assessment ◽  
Low Computational Cost

A significant majority of overhead transmission lines’ (OHLs) outages is due to backflashovers caused by direct lightning strikes: the realistic assessment of the lightning performance is thus an important task. The paper presents the analysis of the lightning performance of an existing 150 kV Italian OHL, namely, its backflashover rate (BFOR), carried out by means of an ATP-EMTP-based Monte Carlo procedure. Among other features, the procedure makes use of a simplified pi-circuit for line towers’ grounding system, allowing a very accurate reproduction of transient behaviours at a very low computational cost. Tower grounding design modifications, aimed at improving the OHL lightning performance, are also proposed and discussed.

scholarly journals Effects of a Crossarm Brace Application on a 275 kV Fiberglass-Reinforced Polymer Crossarm Subjected to a Lightning Impulse

Energies ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 6248
Author(s):  
Muhammad Syahmi Abd Rahman ◽  
Mohd Zainal Abidin Ab Kadir ◽  
Muhamad Safwan Ab-Rahman ◽  
Miszaina Osman ◽  
Shamsul Fahmi Mohd Nor ◽  
...  
Keyword(s):  
Field Strength ◽  
Simulation Study ◽  
Transmission Lines ◽  
Potential Distribution ◽  
Mechanical Performance ◽  
Swing Angle ◽  
Frp Composite ◽  
Reinforced Polymer ◽  
Transmission Towers ◽  
Lightning Impulse

The crossarm is an important component of transmission towers, providing insulation for transmission lines at different voltage ratings. Recently, composite crossarms were widely used as a composite tower component and were found to be the most favorable choice for replacing old wooden crossarms. Owing to the satisfactory pilot operation and multiple sets of testing, fiberglass-reinforced polymer (FRP) composite crossarms have been used in Malaysia in both 132 and 275 kV transmission lines since the late 1990′s. Since then, some modifications have been proposed to improve the mechanical performance of the crossarm, in order to ensure the reliability of its performance. In this investigation, the effect of a proposed improvement, achieved by installing a brace for the crossarm, was investigated numerically. A simulation study was conducted, with a consideration of the lightning impulse voltage (LIV) and swing angle exhibited by the crossarm. The potential and electric field (E-Field) distribution were analyzed and are presented in this paper. It was found that the potential distribution and E-Field strength for the crossarm and the surrounding air were greatly affected by the installation of the brace.

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>

scholarly journals Transient impedance of grounding system with impulse superimposed sinewave

2021 ◽  
Vol 1 (1) ◽  
pp. 8-12
Author(s):  
Sherif Ghoneim ◽  
Ahdab Elmorshedy ◽  
Rabah Amer
Keyword(s):  
System Configuration ◽  
System Operation ◽  
Grounding System ◽  
Several Variables ◽  
Wire Conductor ◽  
Lightning Impulse ◽  
In Series ◽  
Grid Side ◽  
Soil Ionization ◽  
Impulse Current

Investigating the transient performance of grounding systems subject to lightning (impulse or impulse superimposed sinewave) is valuable for protecting the power system and maintaining the system operation. In this work, the grounding system's impedance is computed when an impulse superimposed sinewave is applied to the grounding grid's proposed lumped circuit and grounding system can be simulated as an inductance in series with resistance, and all of them are in parallel with capacitance based on Thione's assumption. Several variables were investigated to study their effects on the grounding system's behavior. The variables were the soil resistivity, soil permittivity, main wire length, grid conductor radius, grid side length, grid configurationand its mesh number. The grounding system configuration  varied between square and rectangular shapes, which connects to the protecting rod via the main wire conductor. A 3.69 kA peak of impulse current was applied to avoid soil ionization. The results indicated the performance of the grounding system when subjecting to impulse current.

Analysis of transient voltages and currents in short transmission lines on frequency-dependent soils☆

2021 ◽  
Vol 194 ◽  
pp. 107103
Author(s):  
T.F.G. Pascoalato ◽  
A.R.J. de Araújo ◽  
S. Kurokawa ◽  
J. Pissolato Filho
Keyword(s):  
Transmission Lines ◽  
Frequency Dependent ◽  
Transient Voltages
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