Lightning conductor system investigation Grounding system experiment Franlin rod system investigation.

This study has been performed as a pilot study for a project regarding the meridional migration of the Intertropical Convergence Zone (ITCZ) and its relationship with lightning activity in the Eastern Tropical Pacific (ETP). Objectives of this study were to analyze and improve lightning data to be used for such a study and to decide on a method and proper time scale of data analysis and ITCZ index development for this study. Exploratory data analysis has been practiced with World Wide Lightning Location Network (WWLLN) data and ITCZ index data. Results suggest that the most beneficial time-scale to be used for the above study is 15 days and that ITCZ estimations can be obtained via the use of precipitation index and cloud top temperature. Lightning data originated from atmospheric systems not associated with the ITCZ has been analyzed. This report proposes that Uppsala University should become part of the World Wide Lightning Location Network, enabling further work regarding this and similar projects.

Whistlers are naturally occurring Very Low Frequency (VLF) phenomena which are the result of lightning-radiated electromagnetic waves propagating in Earth’s plasma environment. Major research into whistlers and their generation began in 1951 and since then much has been discovered about them. This has allowed whistlers to be used as magnetospheric probes. Many issues concerning whistlers are still disputed, however, such as the relationship between the lightning location and the conjugate point of the receiver. A correlation between whistlers detected by the DEMETER satellite above South Africa and lightning located by WWLLN was used to determine the source region for these whistlers. The whistlers were found to originate from lightning strokes as far away as 10000 km. This result is statistically significant. During the course of this research an interesting observation of chorus was made on Marion Island. Since this was the first observation of chorus made on the sub-antarctic Marion Island, conditions surrounding the event were studied in great detail. This led to several interesting observations about the nature of this observation. In particular, during the evolution of the emission, it transformed to hiss, which makes this observation relevant to recent results suggesting that hiss is generated by chorus. It was also found that Marion Island was close to the plasmapause during the observation, which has further implications related to the chorus-hiss relationship. A study of the occurrence of twin whistlers received at Rothera and SANAE IV was conducted. These were whistlers which had propagated from a single ionospheric exit point to both receivers. Rothera and SANAE IV share the same whistler source region, yet the average number of whistlers received at Rothera is an order of magnitude greater than that received at SANAE IV. The twin whistler analysis showed that the most probable reason for this disparity is that whistlers from the source region enter the waveguide preferentially closer to Rothera, making it more likely for them to be received at Rothera than SANAE IV. These results have implications on the nature of sub-ionospheric propagation of whistlers, which is not the same as that of spherics. Finally, a method for tracking tropical cyclones using lightning locations from WWLLN was developed. During the course of this thesis, tropical cyclone Irena was the result of damage on the east coast of South Africa. This presented an opportunity to investigate the ability of WWLLN data to describe the passage of these destructive phenomena near South Africa. The details of this new method are discussed. While the algorithm developed has room for improvement, its performance was tested on the recent tropical cyclone Irina which occurred during 2012. / Thesis (Ph.D.)-University of KwaZulu-Natal, Westville, 2012.

Temporal and wavelet characteristics of initial breakdown pulses are meticulously studied especially during the earliest moment of lightning events. Any possible features during the earliest moment that may exist which lead to either negative cloud-to-ground (CG), positive cloud-to-ground, cloud or isolated breakdown flashes in Sweden are investigated. Moreover, the occurrence of narrow bipolar pulses (NBPs) as part of a CG event that has been recorded from tropical thunderstorms are also included in the investigation. Electric field signatures selected from a collection of waveforms recorded using fast electric field broadband antenna system installed in Uppsala, Sweden and Skudai, South Malaysia are then carefully analyzed in order to observe any similarities or/and differences of their features. Temporal analysis reveals that there are significant distinctions within the first 1 ms among different types of lightning flashes. It is found that a negative CG flash tends to radiate pulses more frequently than other flashes and a cloud flash tends to radiate shorter pulses than other flashes but less frequently when compared to negative CG and isolated breakdown flashes. Perhaps, the ionization process during the earliest moment of negative CG flashes is more rapid than other discharges. Using a wavelet transformation, it can be suggested that the first electric field pulse of both negative CG and cloud flashes experiences a more rapid and extensive ionization process compared to positive CG and isolated breakdown flashes. Further temporal analysis on NBPs found to occur as part of CG flashes show the disparity of the normalized electric field amplitude between the NBPs prior to and after the first return stroke. This indicates that the NBPs intensities were influenced by the return stroke events and they occurred in the same thundercloud. The similarity between the temporal characteristics of NBPs as part of CG flashes and isolated NBPs suggests that their breakdown mechanisms might be similar.

Distributions of air pollutants and their precursors in the troposphere are driven largely by meteorological conditions (e.g., wind, cloud convection, lightning, and precipitation) and emissions such as those of NOx from anthropogenic sources (e.g., fossil fuel combustion) and natural sources (e.g., soils and lightning). As the most polluted regions in the world, North America and East Asia significantly contribute to climate change on both regional and global scales. Therefore, it deserves to investigate the vertical and horizontal distributions of the air pollutants in the troposphere over these two regions to better quantify the interaction between air pollution and climate change, which remains until now largely uninvestigated. Here, a Regional chEmical trAnsport Model (REAM) was developed and applied to examine the uncertainties in modeling the effect of convective transport and lightning NOx production on upper tropospheric chemical tracer distributions over North America, and to identify the features of air pollutions over East Asia.

Thesis (M.S. in Meteorology)--Naval Postgraduate School, March 2010. / Thesis Advisor(s): Durkee, Philip A. Second Reader: Nielsen, Kurt E. "March 2010." Description based on title screen as viewed on April 27, 2010. Author(s) subject terms: Lightning, Thunderstorm, GOES, Geostationary, Satellite, Convection, Convective Initiation, Lightning Initiation, Nowcast, Applied Meteorology. Includes bibliographical references (p. 97-101). Also available in print.

Thesis (Ph. D.)--University of Washington, 2005. / Vita. Includes bibliographical references (p. 104-115).

Σε αυτή την διπλωματική εργασία θα γίνει μελέτη της συμπεριφοράς γραμμών διανομής σε καταπονήσεις από κεραυνούς. Οι κεραυνοί αποτελούν ένα φυσικό φαινόμενο με επικίνδυνα αποτελέσματα για την ασφάλεια των ανθρώπων, των κτιρίων και των ηλεκτρικών συστημάτων. Έτσι, κεραυνοί που πλήττουν άμεσα γραμμές διανομής ή γειτονικό σε αυτές έδαφος, είναι υπεύθυνοι για τα σφάλματα που λαμβάνουμε στο ηλεκτρικό σύστημα. Το αποτέλεσμα της πτώσης κεραυνού μπορεί να οδηγήσει σε στιγμιαίο ή μόνιμο σφάλμα. Στιγμιαίο λέγεται αν αυτό “καθαριστεί” από τις διατάξεις προστασίας και το κύκλωμα να ξαναμπεί σε λειτουργία, ενώ το μόνιμο απαιτεί την εξωτερική παρέμβαση από τεχνικούς για την επαναλειτουργία του κυκλώματος. Οι προβλέψεις για την συμπεριφορά των εναερίων γραμμών διανομής εμπεριέχουν πολλές αβεβαιότητες. Mερικές βασικές παράμετροι όπως η πυκνότητα των κεραυνών, που μετριέται με την πυκνότητα των κεραυνών στο έδαφος (GFD), ή ο υπολογισμός του αριθμού των απευθείας πληγμάτων στην γραμμή απέχουν από την πραγματικότητα. Μελετώντας την εργασία αυτή μπορούμε να δώσουμε ακριβείς προβέψεις σφαλμάτων λόγω κεραυνών σε μια γραμμή διανομής. Στο πρώτο μέρος της εργασίας αναφέρεται η οδηγία της ΙΕΕΕ για τη συμπεριφορά των εναέριων γραμμών διανομής ηλεκτρικής ενέργειας έναντι κεραυνών. Σκοπός της είναι να παρουσιάσει εναλλακτικές λύσεις για τη μείωση των βραχυκυκλωμάτων που προκαλούνται από κεραυνό στις εναέριες γραμμές. Συγκεκριμένα θα προσδιοριστεί η συμπεριφορά των εναέριων γραμμών διανομής σε περίπτωση πτώσης κεραυνού (πλήγματα κεραυνών και βραχυκυκλώματα από επαγόμενη τάση), το επίπεδο μόνωσης των γραμμών διανομής, η προστασία των γραμμών διανομής με προστατευτικό αγωγό καθώς επίσης και η προστασία των γραμμών με αλεξικέραυνα. Στο δεύτερο μέρος της εργασίας, θα αναπτυχθεί η καταγραφή σφαλμάτων και βλαβών λόγω πτώσεως κεραυνών στο δίκτυο της Μ.Τ. σε μετασχηματιστές καθώς και στις γραμμές διανομής Μ.Τ. τα τελευταία πέντε χρόνια (2003 – 2008) στην περιοχή της Αχαίας. Επίσης υπολογίζεται αναλυτικά ο αριθμός των θεωριτικών σφαλμάτων που προκείπτουν σύμφωνα με την παραπάνω οδηγία και γίνεται η συσχέτισή τους με τα πραγματικά αποτελέσματα. Τέλος ακολουθούν κάποια ραβδογράμματα για καλύτρερη κατανόηση των αποτελεσμάτων. / This diploma thesis studies the lightning performance of electric power overhead distribution lines. Lightning is a physical phenomenon which usually has dangerous consequences on people or buildings, and it is also the major cause of faults on typical overhead distribution lines. So a lightning that strikes directly to a distribution line, or to the nearby area is responsible for the damage happening to the electric circuit. Lightning usually causes temporary faults on overhead distribution lines. If the fault is cleared by a breaker or a recloser, the circuit may be successfully reclosed. But it can also cause permanent faults by damaging the equipment, which needs external help in order to restore the damage. Estimates of the lightning performance of distribution lines contain many uncertainties. Some of the basics such as lightning intensity measured by ground flash density (GFD), or estimating the number of direct strikes to a distribution line may have significant errors. Often, rough estimates or generally accepted practices are just as effective as detailed calculations. This guide is intended to provide straightforward estimates of lightning-caused faults. To the first part of this project we can find the “IEEE Guide for Improving the Lightning Performance of Electric Power Overhead Distribution Lines” it’s goal is to present alternative solutions for the reduction of the flashovers caused by the lightning strike on overhead distribution lines. Specifically we deal with the lightning performance of the overhead distribution lines during a lightning case (direct strike or induced flashover), the insulation level of distribution lines, the protection of the distribution lines with a shield wire or with arresters. To the second part of this diploma thesis we can find real fault situations that have happened to the middle voltage distribution circuit to the region of Aegio GREECE the last five years (2003-2008). Moreover there is a detailed way of providing the theoretical number of faults according to this guide, after that follows a comparison between experimental and real values as well as some charts for better understanding of the results.

Σκοπός της εργασίας είναι η βιβλιογραφική ανασκόπηση όσον αφορά τη συμπεριφορά γραμμών μεταφοράς σε καταπονήσεις από κεραυνούς, την περιγραφή των μέσων προστασίας και εγκαταστάσεων της ΔΕΗ καθώς επίσης και την ανάλυση σφαλμάτων μιας πραγματικής γραμμής μεταφοράς λόγω πτώσεων κεραυνούστην περιοχή της Αχαΐας. / The purpose of work is the bibliographic examination, which concerns the lightning perfomance of electric power overhead distribution lines, the description protection's methods and installations of National Electricity Company, as well as faults analysis of real transmission line in the region of Achaia.

Στην παρούσα διπλωματική εργασία έγινε μια προσπάθεια να γίνει η στατιστική ανάλυση των πληγμάτων των κεραυνών κατά τα τελευταία έντεκα χρόνια (2000-2010). Στο πρώτο κεφάλαιο παρουσιάζεται το φαινόμενο του κεραυνού, τα είδη των κεραυνών και τα φυσικά χαρακτηριστικά του, ενώ στο δεύτερο κεφάλαιο παρουσιάζονται οι επιπτώσεις αυτών. Στο τρίτο κεφάλαιο αναλύονται τα δεδομένα σχετικά με τους θανάτους και τους τραυματισμούς ανθρώπων, τους θανάτους ζώων, τις πυρκαγιές, τα πλήγματα σε εγκαταστάσεις, κτήρια και αεροπλάνα που οφείλονται σε πτώσεις κεραυνών για μια χρονική περίοδο έντεκα χρόνων, από το 2000 ως το 2010. Αυτά τα δεδομένα συλλέχθηκαν κυρίως από τα Μέσα Μαζικής Ενημέρωσης της χώρας με σκοπό οι πληροφορίες να είναι διασταυρωμένες και αξιόπιστες και για να έχουμε μια πλήρη άποψη για τα γεγονότα. Τα στοιχεία έχουν κατανεμηθεί σε χρονιές, μήνες και ημέρες των συμβάντων. Επιπλέον, εισάγεται ο σχετικός συντελεστής θανάτων από κεραυνούς Dr, ο οποίος εκφράζει το σχετικό αριθμό θανάτων εξαιτίας κεραυνού σε μια χώρα ή περιοχή λαμβάνοντας υπ’ όψιν τον πληθυσμό, την έκταση και την δραστηριότητα των κεραυνών (Ng). Αυτός ο συντελεστής θα μπορούσε να είναι απλώς ένα κριτήριο για την αποτελεσματικότητα των μέτρων προστασίας από κεραυνούς, καθώς και για τα αποτελέσματα των εκπαιδευτικών και ενημερωτικών εκστρατειών για την προστασία από τους κεραυνούς. Από την ανάλυση των δεδομένων για τους θανάτους ανθρώπων εξαιτίας κεραυνού συμπεράναμε ότι έχουμε ένα μέσο όρο των 2 απωλειών ανά έτος (22 απώλειες συνολικά) και ότι το 95% των συμβάντων σημειώθηκαν κατά τους μήνες του μεσοκαλόκαιρου (Μάιος-Σεπτέμβριος). Ο Ιούνιος είναι ο μήνας με τα περισσότερα συμβάντα. Τα θύματα ήταν κυρίως αγρότες και βοσκοί. Όσο αναφορά στους τραυματισμούς έχουμε ένα μέσο όρο των 1,64 τραυματιών ανά έτος και το 83% των συμβάντων να γίνεται κατά τους μήνες του μεσοκαλόκαιρου, με τον Μάιο να είναι ο «χειρότερος» από τους δώδεκα μήνες. Κατά την εντεκάχρονη περίοδο παρατηρήθηκαν 178 θάνατοι ζώων και ο μέσος όρος είναι 16,18 ανά έτος με μόλις εφτά πλήγματα κεραυνών. Τον Ιούλιο σημειώθηκαν οι περισσότεροι θάνατοι και το 83% τους μήνες του μεσοκαλόκαιρου. Οι πυρκαγιές που σημειώθηκαν ήταν 67 με το 85% να είναι δασικές. Το 2008 και το 2009 είχαμε θεαματική αύξηση των πυρκαγιών εξαιτίας κεραυνού. Όπως και στις προηγούμενες περιπτώσεις, έτσι και εδώ, το μεγαλύτερο ποσοστό των πυρκαγιών σημειώθηκαν κατά τους μήνες του μεσοκαλόκαιρου (94%). Ο μέσος όρος των πληγέντων εγκαταστάσεων από κεραυνό είναι 4,4 ανά έτος (48 συμβάντα συνολικά). Ο μήνας με τα περισσότερα πλήγματα είναι ο Ιούνιος. Τα κτήρια τα οποία επλήγησαν από κεραυνό ανέρχονται στα 21 με μέσο όρο 1,9 ανά έτος, με το έτος 2009 να είναι αυτό στο οποίο σημειώθηκαν τα περισσότερα συμβάντα. Η κατανομή των πληγμάτων στους μήνες είναι ομαλή. Επιπλέον, καταγράψαμε 7 αεροπλάνα τα οποία επλήγησαν από κεραυνό κατά την εντεκάχρονη έρευνα και αυτό μας δίνει ένα μέσο όρο των 0,64 αεροπλάνων ανά έτος. Επίσης, έγινε η κατανομή όλων των συμβάντων όλων των κατηγοριών στις ημέρες της εβδομάδος χωρίς όμως να βγει κάποιο ενδιαφέρον συμπέρασμα. Τέλος, στο ΠΑΡΑΡΤΗΜΑ παρουσιάζονται τα συμβάντα λεπτομερώς σύμφωνα με τις εκάστοτε πηγές, οι οποίες είναι και αυτές διαθέσιμες. / This study is an attempt to make the statistical analysis of lightning strikes over the last eleven years (2000-2010). The first chapter describes the phenomenon of lightning, types of lightning and natural features, while the second section outlines the implications of these. In the third chapter data analysis concerning deaths, injuries, animal deaths, fires, strokes at facilities, structures and airplanes from lightning in Greece is presented , for a period of eleven years, from 2000 to 2010. These data were collected mainly from the media of the country so that information will be crossbred and reliable and to get a full view of all events. The data are based on distribution in years, months and days of occurrence. Furthermore, the relative lightning death indicator Dr is introduced and expresses the relative number of lightning deaths in a country taking into account its population, its area and the lightning activity Ng. This indicator could simply be a criterion for the effectiveness of lightning protection, and for the outcomes of education and information campaigns for the protection from lightning. From the data analysis on lightning deaths we have concluded an average of two casualties per year (22 total loss) and that 95% of the incidents occurred during the months of Midsummer (May-September). June is the month with most deaths. The victims were mainly farmers and shepherds. In reference to the injuries we have an average of 1.64 injuries per year and 83% of incidents taken place during the months of Midsummer, while May is presented as the "worst" of the twelve months. During the eleven-year period 178 animal deaths were observed and the average is 16.18 per year for just seven lightning strikes. In July are recorded the most deaths and 83% happened during the months of Midsummer. The fires that occurred were 67, while the 85% were at forests. In 2008 and 2009 had a dramatic increase of fires caused by lightning strikes. As in previous cases, the majority of fires occurred during the months of Midsummer (94%). The average of affected facilities from lightning is 4.4 per year (48 events total). The months with the most strokes is June. The structures which were hit by lightning amounted to 21 with an average of 1.9 per year, while the year 2009 is the one in which most events occurred. The distribution of strokes in months is normal. 7 airplanes affected by lightning during the eleven-year research were also recorded and this gives us an average of 0.64 airplanes per year. The distribution of all events of all categories in the days of the week is also presented, but we did not get to an interesting conclusion. Finally, in the ANNEX the events are presented in details in accordance with relevant sources, which are also available.