scholarly journals An Analysis of Reducing Back Flashover Faults with Surge Arresters on 69/138 kV Double Circuit Transmission Lines Due to Direct Lightning Strikes on the Shield Wires

2014 ◽  
Author(s):  
N. Malcolm ◽  
R.K. Aggarwal
Keyword(s):  
Transmission Lines ◽  
Lightning Strikes ◽  
Surge Arresters

scholarly journals Determination of Cumulative Distribution Function of the Crest Value of the Lightning Current Circulating Through Line Surge Arresters

2020 ◽  
Vol 69 (2) ◽  
pp. 11-18
Author(s):  
Goran Levačić ◽  
Alain Xémard ◽  
Miroslav Mesić
Keyword(s):  
Distribution Function ◽  
Transmission Line ◽  
Transmission Lines ◽  
Cumulative Distribution Function ◽  
Cumulative Distribution ◽  
Lightning Strikes ◽  
Surge Arresters ◽  
Lightning Current ◽  
Calculation Results

For the selection and design of line surge arresters (LSA), it is essential to know the characteristics of the lightning current circulating through LSA. When lightning strikes a transmission line, only a part of the lightning current circulates through LSA.This part mostly depends on the point of impact, and the characteristic of the lightning stroke current. The determination of the cumulative distribution function of the lightning current circulating through arresters is presented in first part of the paper. It can be applied on transmission lines where LSAs will be installed to protect the line against the effect of atmospheric discharges.Second part of paper presents the calculation results of the cumulative distribution function of the lightning current circulating through arresters for particular 110 kV transmission line located in an area with high lightning activity.

scholarly journals Assessment of Overvoltage and Insulation Coordination in Mixed HVDC Transmission Lines Exposed to Lightning Strikes

Energies ◽  
2019 ◽  
Vol 12 (21) ◽  
pp. 4217
Author(s):  
Mansoor Asif ◽  
Ho-Yun Lee ◽  
Kyu-Hoon Park ◽  
Ayesha Shakeel ◽  
Bang-Wook Lee
Keyword(s):  
Transmission Line ◽  
Transmission Lines ◽  
Protective Level ◽  
Lightning Strikes ◽  
Hvdc Transmission ◽  
Surge Arresters ◽  
Hvdc Transmission Lines ◽  
Lightning Impulse ◽  
Insulation Coordination ◽  
Front Model

Many geographical constraints and aesthetic concerns necessitate the partial use of cable sections in the High Voltage DC (HVDC) transmission line, resulting in a mixed transmission line. The overhead sections of mixed lines are exposed to lightning strikes. The lightning strikes can not only result in flashover of overhead line (OHL) insulators but can enter the cable and permanently damage its insulation if adequate insulation coordination measures are not taken. In this work, we have analyzed the factors that affect the level of overvoltage inside the cable by simulating a fast front model in PSCAD. It has been determined that surge arresters must be provided at cable terminals when the length of cable sections is less than 16 km to limit the core-ground overvoltage within the lightning impulse protective level (LIPL). The level of sheath-ground overvoltage is independent of the length of cable; however, it can be limited within LIPL by lowering the sheath grounding impedance to 1.2 Ω. Insulation coordination measures do not impact the likelihood of OHL insulators’ flashover. The flashover performance of OHL can be improved by lowering the footing impedance of the second tower closest to the cable terminals, which is otherwise most likely to flashover.

scholarly journals Effect of indirect lightning strike to 66kV transmission line in Java-Bali system

2018 ◽  
Vol 197 ◽  
pp. 11001
Author(s):  
Aristo Adi Kusuma ◽  
Putu Agus Aditya Pramana ◽  
Brian Bramantyo S.D.A. Harsono ◽  
Buyung Sofiarto Munir
Keyword(s):  
Transmission Line ◽  
Transmission Lines ◽  
Lightning Strike ◽  
Actual Condition ◽  
Peak Current ◽  
Lightning Strikes ◽  
Detection Systems ◽  
Current Magnitude ◽  
Lightning Detection ◽  
Insulator Flashover

Based on Java-Bali grid disturbance data, the 66kV transmission lines that is close to or intersect with 150kV or 500kV transmission line is often experienced earth fault due to insulator flashover. The insulator flashover can be caused by indirect lightning strike since lightning strikes tend to strike higher structure. Therefore, this paper will determine the effect of indirect lightning strike on 150kV or 500kV transmission line to 66kV transmission line by modeling and simulation using application of transient analysis. Variation of lightning peak current magnitude and gap between 66kV transmission line and transmission line with higher voltage is performed during simulation. The range of peak current magnitude follows the data from lightning detection systems, while the value of gap follows the data from actual condition. It is found that higher current peak and closer gap will cause higher transient overvoltage on insulator of 66kV transmission line thus insulator flashover may occur more frequent. Addition of earth wire on 66kV transmission line and gap between each transmission by organizing the sag of conductor can be performed to minimize the insulator flashover.

scholarly journals Electric systems failures produced by CG lightning in Eastern Amazonia

2014 ◽  
Vol 29 (spe) ◽  
pp. 31-40 ◽  
Author(s):  
Ana Paula Paes dos Santos ◽  
José Ricardo Santos de Souza ◽  
Everaldo Barreiros de Souza ◽  
Alexandre de Melo Casseb do Carmo ◽  
Wanda Maria do Nascimento Ribeiro
Keyword(s):  
Energy Distribution ◽  
Transmission Lines ◽  
Distribution Systems ◽  
Electric Energy ◽  
Electricity Distribution ◽  
Power Outages ◽  
Lightning Strikes ◽  
Area Of Interest ◽  
The Pacific ◽  
Cg Lightning

Operational records of power outages of the electric energy distribution systems in eastern Amazonia presented a large number of events attributed to lightning strikes, during the 2006 to 2009 period. The regional electricity concessionary data were compared to actual lightning observations made by SIPAM's LDN system, over two areas where operational sub systems of transmission lines are installed. Statistical relations were drawn between the monthly lightning occurrence density and the number of power outages of the electric systems for both areas studied. The results showed that, although with some delays between these variables peaks, the number of power disruptions has a tendency to follow the behavior of the lightning occurrence densities variations. The numerical correlations were positive and may be useful to the transmission lines maintenance crews at least for the Belém-Castanhal electricity distribution sub system. Evidence was found, that the SST's over certain areas of the Pacific and Atlantic Oceans, influence convection over the area of interest, and may help to prognosticate the periods of intense electric storms, requiring repair readiness for the regional electric systems.

scholarly journals A Methodology for Optimal Design of Transmission Lines to Protection against Lightning Surges in Presence of Arresters

2020 ◽  
Vol 9 (1) ◽  
pp. 105-110
Author(s):  
R. Shariatinasab ◽  
R. Azimi
Keyword(s):  
Transmission Lines ◽  
Geometric Model ◽  
Design Parameters ◽  
Target Number ◽  
Planning Stage ◽  
Shielding Failure ◽  
Surge Arresters ◽  
The Monte Carlo Method ◽  
Optimal Value

In this paper, a methodology for determination of the optimal value of protection design parameters, i.e. tower footing resistance, insulation strength, and surge arresters’ rating in the planning stage of transmission lines (TLs) is presented. This method calculates the shielding failure flashover rate (SFFOR) of TLs, based on Electro-geometric model (EGM) of TLs, and the back flashover rate (BFR) of TLs, based on the Monte Carlo method, in which the accuracy of the proposed methodology has been verified by comparing the resultant results with those obtained with the use of the IEEE FLASH program. The proposed method can be directly used to achieve the minimum lightning flashover rate (LFOR) of TLs by the minimum investment cost. Also, it can be used, indirectly, for determination of the appropriate value of the footing resistance, insulation strength and arresters’ rating to satisfy any target number of LFOR that might be specified by the utilities or standards.

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 Evaluation of a Direct Lightning Strike to the 24 kV Distribution Lines in Thailand

Energies ◽  
2019 ◽  
Vol 12 (16) ◽  
pp. 3193 ◽  
Author(s):  
Pornchai Sestasombut ◽  
Atthapol Ngaopitakkul
Keyword(s):  
Electromagnetic Transients ◽  
Lightning Strike ◽  
Significant Variable ◽  
Line System ◽  
Lightning Strikes ◽  
Underground Cables ◽  
Ground Resistance ◽  
Distribution Lines ◽  
Surge Arresters ◽  
Distribution Line

This paper evaluates the effect of a lightning strike directly on the 24 kV distribution lines in Thailand, where such strikes are one of the main causes of power outages. The voltage across the insulator, and the arrester energy absorbed due to the lightning, need to be analyzed for different grounding distances of the overhead ground wire, ground resistance, lightning impact positions, and lightning current waveforms. Analysis and simulations are conducted using the Alternative Transients Program/Electromagnetic Transients Program (ATP/EMTP) to find the energy absorbed by the arrester and the voltages across the insulator. The results indicate that when surge arresters are not installed, the voltage across the insulator at the end of the line is approximately 1.4 times that in the middle of the line. In addition, the ground resistance and grounding distance of the overhead ground wire affect the voltage across the insulator if the overhead ground wire is struck. When surge arresters are installed, a shorter grounding distance of the overhead ground wire and a lower ground resistance are not always desirable; this is because they reduce the back-flashover rate and the voltage across the insulator if lightning strikes the overhead ground wire. However, lightning strikes to the phase conductor result in high arrester energy and the possibility that the arrester will fail. Furthermore, the tail time of the lightning waveform is a significant variable when considering the energy absorbed by the arrester, whereas the front time is important for the voltage across the insulator. In case lightning strikes directly on the connected point between the overhead lines and the underground cables, the distribution line system is protected only by the lightning arrester at the connection point. The overvoltage at the connection point is lower than the basic impulse level at 24 kV of 125 kV, but the overvoltage at the end of the cable is still more than 125 kV in case the cable is longer than 400 m. When the distribution line system is protected by the lightning arrester at both the connection point and the end of the cable, it results in overvoltage throughout the cable is lower than the critical flashover of insulation. This method is the best way to reduce the failure rate of underground cables and equipment that are connected to the distribution line system.

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