Abstract:

The medium voltage system performance analyses front lightning discharges is very dependent on its modeling. As the model approaches the reality, more it becomes extremely complex and time expensive, as a result, it generally leads to the adoption of some sort of simplifications and approximations.
The present work aims at the study of a large variety of effects of the lightning discharges, its impacts and preponderant factors for analysis in different real systems, as far as searching for a balance between the model's approximation and the resultant errors.
With this in mind, it uses models that are more precise, stochastic process simulations, electromagnetic transient simulations, real information from the networks and statistical analyses.
Therefore, it is possible to establish the main intervention points for the improvement of the medium voltage overhead distribution system performance front lightning discharges.

Introduction:

The lightning discharges are one of the main causes of failures, playing a significant role in the interruptions and damages, many times permanent, in the electrical systems. Consequently, it results in major losses for the utilities and society.
These discharges can inject surges in the electrical systems basically by two ways: induction, through the coupling of the electromagnetic fields with the conductors; or direct impact in the conductors.
For the electric distribution systems, the lightning discharges have a great impact due to predominantly overhead line configuration and its general great extension. As a result, it is assumed that about one-third of the failures is caused by lightning.
Brazil, by the tropical location, has one of the biggest incidences of lightning in the world, where it is estimated that they can reach the order of 70 million discharges per year, which can make damages and losses reaching the order of US$ 250 million or more.
With the privatization of the electrical utilities, the Brazilian National Agency of Electrical Energy (ANEEL, in Portuguese) started to demand the continuous improvement of quality, continuity and reliability in the supply of electric energy.
The consumers also are more demanding; therefore, it becomes necessary an increase in the investments in research and development of new techniques and technologies aiming at electrical energy supply improvement. Therefore, the effects study of lightning discharges in the electrical power systems can be considered an essential item.
The objective of this paper is to study the large variety of effects of the lightning discharges, its impacts and preponderant factors for analysis into different real distribution systems.
Thus, establishing the main intervention points for the performance improvement by the impact analysis of the equipment installed in the network, as an example: transformers, insulators, and surge arresters.
For this purpose, an entire analysis methodology and simulation need to be developed, generating a valid procedure to infer the behavior of the system and of the installed equipment in the occurrence of a lightning surge.
The development of this methodology has involved since the elaboration of a computer program for the treatment, exhibition and use of the geographic information databases of the system, as well as simulation, stochastic analysis, probability and statistics of the occurrence of surges caused by lightning.
In addition, an interface module was developed to do electromagnetic transient simulations, where all the dynamics of the distribution and dissipation of the surge will be detailed and analyzed, together with the impact into the equipment and elements of the system.

References:

[1] Marco A. M. Saran, “Lightning Overvoltage’s in Medium Voltage Lines”, Master Thesis, Federal University of Itajubá, Brazil, Feb. 2009.
[2] Manuel L. B. Martinez, Pedro H. M. dos Santos, “Study of the Induced Voltages in Distribution Networks, Guide for the Performance Improvement of the Overhead Distribution under Lightning Discharges”, High Voltage Lab., Federal University of Itajubá, Brazil, March 2004;
[3] Carlo A. Nucci, Mario Paolone, “Calculation of Induced Voltages in Medium Voltage Overhead Systems due to Lightning Strokes Using the LIOV Code”, Report for the Second Phase of the R&D Project for the AES Sul Utility, October 2003;
[4] Marco A. M. Saran, Rafael R. Bonon, Manuel L. B. Martinez, Hermes R. P. M. De Oliveira, Carlo A. Nucci, Mario Paolone, “Performance of Medium Voltage Overhead Distribution Lines Against LightningInduced Voltages: A Comparative Analysis”, GROUND’06 e 2nd LPE - International Conference on Grounding and Earthing & 2nd International Conference on Lightning Physics and Effects, Maceió, Brazil, November, 2006;
[5] Marco A. M. Saran, Manuel L. B. Martinez, Hermes R. P. M. De Oliveira, “Performance of Medium Voltage Urban And Rural Distribution Lines Front Lightning Discharges And Induced Surges”, GROUND’06 e 2nd LPE - International Conference on Grounding and Earthing & 2nd International Conference on Lightning Physics and Effects, Maceió, Brazil, November, 2006;
[6] Marco A. M. Saran, Rafael R. Bonon, Manuel L. B. Martinez, Hermes R. P. M. De Oliveira, Carlo A. Nucci, Mario Paolone, “Performance of Medium Voltage Overhead Distribution Lines Against Lightning Discharges”, International CIGRÉ Symposium – TPLEPS – Transient Phenomena In Large Electric Power Systems, Zagreb, Croatia, April 2007;
[7] Marco A. M. Saran, Manuel L. B. Martinez, Hermes R. P. M. de Oliveira, “Performance of Medium Voltage Urban and Rural Distribution Lines Front Lightning Discharges and Induced Surges”, 15th International Symposium on High Voltage Engineering, Ljubljana, Slovenia, August 2007;
[8] Marco A. M. Saran, Manuel L. B. Martinez, Carlo A. Nucci, Mario Paolone, Hermes R. P. M. de Oliveira, “Performance Analysis of Medium Voltage Overhead Distribution Line Against Lightning”, 19th CIRED, International Conference on Electricity Distribution, Vienna, Austria, May 2007;
[9] Marco A. M. Saran, Manuel L. B. Martinez, Carlo A. Nucci, Mario Paolone, Hermes R. P. M. de Oliveira, “Comparative Performance of Medium Voltage Overhead Distribution Lines Designs Submitted to Induced Voltages”, Power Tech, Lausanne, Switzerland, July 2007;
[10] IEEE Guide for Improving the Lightning Performance of Electric Power Overhead Distribution Lines, IEEE Std 1410-2004, T&D Committee, IEEE Power Engineering Society;
[11] John G. Anderson, Thomas A. Short, “Algorithms for Calculation of Lightning Induced Voltages on Distribution Lines”, IEEE Transactions on Power Delivery, Volume 8, Number 3, Pages 1217-1225, July 1993;
[12] Parameters of Lightning Strokes: A Review, Lightning and Insulator Subcommittee of T&D Committee, IEEE Transactions on Power Delivery, Vol. 20, No. 1, January 2005;
[13] Pedro H. M. dos Santos, “Performance Analysis of Medium Voltage Circuits Front Induced Lightning Impulses”, Master Thesis, Federal University of Itajubá, Brazil, March 2007;
[14] Ricardo G. de Oliveira Jr., “Induced Voltages in Medium Voltage Lines”, Master Thesis, Federal University of Itajubá, Brazil, August 2008;
[15] Andrew R. Hileman, “Insulation Coordination for Power Systems”, Marcel Dekker Inc., 1999;
[16] G. Vernon Cooray, “The Lightning Flash”, IEE Power Series, Volume 34, 2003;
[17] Lou van der Sluis, “Transients in Power Systems”, John Wiley & Sons, 2001;
[18] Mustafa Kizilcay, “Power System Transients and Their Computation”, Osnabrück University of Applied Sciences, Germany, 2000;
[19] Protection of MV and LV Networks against Lightning, Joint CIGRÉCIRED Working Group C4.4.02, 2005;

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