Parallel processing applied to the design of concrete encased grounding electrodes

This work presents the authors investigation regarding the application of parallel processing to the design of grounding systems, comprising concrete encased electrodes. The natural parallelism of the involved tasks and the large time-consuming characteristic of sequential processing for this kind of application justify the use of high performance computation. This design problem presents two main approaches for parallelism exploring. This work shows the advantages of parallel processing for generation of a geometric coefficient matrix, which describes the basic relations among currents and potentials at the grounding system. The grounding model has been developed at Federal University of Minas Gerais and, for implementing the parallel algorithm version, a computational tool (CPAR), which was developed in Polytechnic School of São Paulo University, was employed.Facultad de Informátic

Effects of macromodeling on the simulation of transient events caused by direct lightning to overhead power lines

This paper aims at assessing the relevance of the coupling effects among the main components of overhead power lines in their lightning response, namely, tower, grounding electrodes, and shield wire(s). Mutual coupling effects are investigated by simulation, using an electromagnetic model. The analyses are performed in the frequency and time domain, by considering, respectively, the input impedance at the node of current injection and the overvoltages rising at the same node. The study is conducted considering different configurations for current excitation and three arrangements of grounding electrodes, with the corresponding soil properties. From the analysis of the results, it appears that the effects of electromagnetic coupling among the considered system components affects only marginally the lightning response of the line, being much less relevant than the effects of the uncertainties on the values of electrical parameters of the local soil. This confirms the validity of the macromodeling approach and denotes that the accuracy of the results is overall dependent on the suitability of models adopted for each component; in particular, the proper representation of the grounding system is proven as essential to the successful prediction of overvoltages at the tower top

Effects of macromodeling on the simulation of transient events caused by direct lightning to overhead power lines

This paper aims at assessing the relevance of the coupling effects among the main components of overhead power lines in their lightning response, namely, tower, grounding electrodes, and shield wire(s). Mutual coupling effects are investigated by simulation, using an electromagnetic model. The analyses are performed in the frequency and time domain, by considering, respectively, the input impedance at the node of current injection and the overvoltages rising at the same node. The study is conducted considering different configurations for current excitation and three arrangements of grounding electrodes, with the corresponding soil properties. From the analysis of the results, it appears that the effects of electromagnetic coupling among the considered system components affects only marginally the lightning response of the line, being much less relevant than the effects of the uncertainties on the values of electrical parameters of the local soil. This confirms the validity of the macromodeling approach and denotes that the accuracy of the results is overall dependent on the suitability of models adopted for each component; in particular, the proper representation of the grounding system is proven as essential to the successful prediction of overvoltages at the tower top

Problemas de calidad de energía causados por termitas en cables subterráneos de 138kv

Este artículo discute problemas encontrados en la operación de cables subterráneos en los sistemas de transmisión de CEMIG, con énfasis en las fallas de aislamiento causadas por las termitas. Problema que ha sido la fuente de muchas interrupciones programadas y no programadas en los últimos años, llevando a significantes costos de mantenimiento. Experiencias con las prácticas corrientes planeadas para detectar y prever este modo de falla esta descrito en este trabajo. Se establece que nuevos procedimientos son necesarios para mejorar durante el funcionamiento, la detección prefalla. La mejora de pruebas se espera que contribuya tanto a aumentar la vida útil de los cables subterráneos en operación, como a reducir los costos de mantenimiento.This paper discusses problems found in the operation of underground cables in the transmission system of CEMIG, with emphasis on insulation failures caused by termites. This problem has been the source of many scheduled and nonscheduled interruptions in later years, leading to significant maintenance costs. Experience with current practices designed to detect and prevent this failure mode is described. It is argued that new procedures are needed for improved on-line, pre-failure detection. Test improvement will hopefully contribute to increase the lifetime of underground cables currently in use, as well as to reduce maintenance costs

Parallel processing applied to the design of concrete encased grounding electrodes

This work presents the authors investigation regarding the application of parallel processing to the design of grounding systems, comprising concrete encased electrodes. The natural parallelism of the involved tasks and the large time-consuming characteristic of sequential processing for this kind of application justify the use of high performance computation. This design problem presents two main approaches for parallelism exploring. This work shows the advantages of parallel processing for generation of a geometric coefficient matrix, which describes the basic relations among currents and potentials at the grounding system. The grounding model has been developed at Federal University of Minas Gerais and, for implementing the parallel algorithm version, a computational tool (CPAR), which was developed in Polytechnic School of São Paulo University, was employed.Facultad de Informátic

Aplicação de processamento paralelo no projeto de aterramentos encapsulados

Este trabalho apresenta investigações sobre a aplicação de processamento paralelo no projeto de aterramentos encapsulados. O grau de paralelismo da tarefa e o elevado tempo computacional gasto pelo processamento seqüencial motivam a utilização da computação de alto desempenho na sua solução. A exploração do paralelismo se apresenta sob diferentes enfoques e, neste trabalho, são apresentados os ganhos obtidos na geração da matriz de coeficientes geométricos, que descreve as relações básicas entre as correntes e potenciais no sistema. A modelagem de aterramento tem sido objeto de pesquisa na Universidade Federal de Minas Gerais e o algoritmo paralelo foi elaborado utilizando-se a ferramenta computacional CPAR, que oferece recursos para paralelização e foi desenvolvida na Escola Politécnica da Universidade de São Paulo.I Workshop de Procesamiento Distribuido y Paralelo (WPDP)Red de Universidades con Carreras en Informática (RedUNCI

Aplicação de processamento paralelo no projeto de aterramentos encapsulados

Este trabalho apresenta investigações sobre a aplicação de processamento paralelo no projeto de aterramentos encapsulados. O grau de paralelismo da tarefa e o elevado tempo computacional gasto pelo processamento seqüencial motivam a utilização da computação de alto desempenho na sua solução. A exploração do paralelismo se apresenta sob diferentes enfoques e, neste trabalho, são apresentados os ganhos obtidos na geração da matriz de coeficientes geométricos, que descreve as relações básicas entre as correntes e potenciais no sistema. A modelagem de aterramento tem sido objeto de pesquisa na Universidade Federal de Minas Gerais e o algoritmo paralelo foi elaborado utilizando-se a ferramenta computacional CPAR, que oferece recursos para paralelização e foi desenvolvida na Escola Politécnica da Universidade de São Paulo.I Workshop de Procesamiento Distribuido y Paralelo (WPDP)Red de Universidades con Carreras en Informática (RedUNCI

Potential use of space-based lightning detection in electric power systems

Information about lightning activity and its parameters is necessary to design and evaluate the lightning protection of an electrical power system. This information can be obtained from ground-based lightning detection networks that provide information on cloud-to-ground lightning strikes with a location accuracy of few hundred meters. Recently, the first satellite-based lightning optical detectors are operating continuously from geostationary orbits. These imagers observe the luminosity escaping from clouds to detect and locate total lightning activity with a spatial accuracy of several kilometers. This allows delineating the initiation and propagation (sometimes over tens to hundreds of kilometers before striking the ground) not observable by the ground-based networks. In this paper, we explore the use of this new technology for lightning protection in power systems. We focus on tall objects such as wind turbines and overhead transmission lines. We show how the optical detections allow identifying lightning flashes that likely produce continuing currents. This provides additional information for the identification of dangerous events and also can be used to estimate the number of upward-flashes from tall objects triggered by a nearby flash. The analysis of a transmission line shows the concentration of faults in the areas of high total lightning flash density. We found regional variations of the optical energy of the flashes along the line.This work was supported by research grants ESP2017-86263-C4-2-R funded by MCIN/AEI/ 10.13039/501100011033 and by “ERDF A way of making Europe”, by the “European Union”; and Grants PID2019- 109269RB-C42 and ENE2017-91636-EXP funded by MCIN/AEI/ 10.13039/501100011033. S. Goodman was in part supported by NASA Grant 80NSSC18K1689. M. M. F. Saba was in part supported by research grants 2012/15375–7 and 2013/05784–0, from Sao ˜ Paulo Research Foundation (FAPESP). S. Visacro was supported by a research grant (307381/2019–6) of the Brazilian National Council of Technological and Scientific Development (CNPq). The GLM data are available from the NOAA National Centers for Environmental Information (NCEI) and Cloud Service Providers (e.g., Amazon Web Services, AWS). The LIS data are available from the NASA GHRC Distributed Active Archive Center (DAAC) (https:// https://ghrc.nsstc.nasa.gov/home/access-data. The power system information for the 500 kV transmission line is provided by ISA-INTERCOLOMBIA and is supported by L. Porras.Peer ReviewedPostprint (author's final draft

THE INFLUENCE OF GROUNDING ON THE TRANSFERENCE OF SURGES FROM MV TO LV NETWORKS.

In this work, results and analyses concerning the influence of grounding on the transference of lightning-related surges from medium voltage (MV) to low voltage (LV) networks are presented. For such evaluations a simplified model representing typical features of Brazilian rural lines was implemented in the EMTP. Sensitivity analyses were performed in order to evaluate the impact of transferred surges on LV loads. Main results indicate the need of obtaining low values for the ratio between transformer grounding (Rt) and consumer grounding (Rc), preferably with reduced values for both