IEEE TRANSACTIONS ONELECTROMAGNETIC COMPATIBILITY, VOL. 61, NO. 3, JUNE 2019 745 Features of Upward Lightning Measured in a Tropical Region and Their Potential to Cause Hazardous Effects Silverio Visacro , Fellow, IEEE, Miguel Guimarães , Pedro Mattioli , and Maria Helena Murta Vale Abstract—Features of upward lightning and their potential to yield hazardous effects are discussed based on original fast video and simultaneous records of current and electric field of a recent event measured at Morro do Cachimbo Station (MCS). Statistics of parameters of 20 negative upward lightning measured in this tropical area since 2010 are presented and the main parameters that express their potential to produce damages are compared to the counterparts in temperate regions. The events measured at MCS can be classified in two categories, according to the charge of their initial continuous current: ∼6 C (14 events) and ∼0.9 C (6 events), with variations lower than 8%. MCS events have significantly lower charge, shorter duration, and much lower specific energy in relation to events measured in temperate regions. Thus, they have lower potential to yield hazardous effects. Index Terms—Lightning, lightning currents, Lightning current parameters, lightning current statistical distributions. I. INTRODUCTION T HE severity of lightning effects in electric systems is ex- pressed by the damages they produce in the systems’ com- ponents or by insulation failures, which affect the operation of the systems, leading frequently to serious occurrences, such as outages. In the overwhelming majority of cases, the lightning current is the source of both effects, insulation failures and damages. Insulation failures are typically associated with high-intensity and short-duration pulses of current, corresponding to return stroke (RS) currents. Damages, such as those in Fig. 1, are typ- ically associated with low-intensity and long-duration currents, corresponding to either continuing currents (CC) or the initial continuous current (ICC) of upward lightning. Manuscript received December 8, 2018; revised March 15, 2019; accepted April 19, 2019. Date of publication June 4, 2019; date of current version June 11, 2019. The work of S. Visacro was supported by the Brazilian National Council of Technological and Scientific Development (CNPq) under Grant 310564/2016-6. (Corresponding author: Silverio Visacro.) S. Visacro, P. Mattioli, and M. H. Murta Vale are with the LRC— Lightning Research Center, Federal University of Minas Gerais, Belo Horizonte 30315-220, Brazil (e-mail: lrc@cpdee.ufmg.br; pedro123matti@hotmail.com; mhelena@cpdee.ufmg.br). M. Guimarães is with the Electrical Engineering Department, Centro Federal de Educacao Tecnologica de Minas Gerais, Belo Horizonte 30510-000, Brazil (e-mail: miguelbgn@gmail.com). Color versions of one or more of the figures in this paper are available online at http://ieeexplore.ieee.org. Digital Object Identifier 10.1109/TEMC.2019.2916500 Fig. 1. Destructive effects caused by heating yielded by lightning currents. (a) Illustration of non-conductive victim: corner of a masonry buildings. (b) De- tail of “a”. (c) Illustration of a conductive victim: optical ground wire (OPGW). (d) Detail of “c.” In this respect, it is fundamental to characterize the features of lightning currents and to quantify their parameters for different types of lightning events. Recently published CIGRE documents [1], [2] comprehensively address these parameters. The literature has dedicated most attention to RSs of negative downward lightning and their effects. Differently, this paper fo- cuses on the features of upward lightning measured in tropical regions that make this kind of event a potential source of dam- age to electric systems’ components. To address this issue, this paper takes as reference the updated data of upward lightning measured at Morro do Cachimbo Station (MCS), placed in a tropical area in Brazil. In particular, it considers the fast video and simultaneous records of current and electric field of a nega- tive upward lightning measured in 2018 to analyze the features of this type of event. II. DAMAGES CAUSED BY LIGHTNING Physical damages are caused by heating and consequent ef- fects, produced by lightning currents. The specific energy (also 0018-9375 © 2019 IEEE. Personal use is permitted, but republication/redistribution requires IEEE permission. See http://www.ieee.org/publications_standards/publications/rights/index.html for more information.