Pub Date : 2022-10-02DOI: 10.1109/ICLP56858.2022.9942612
Z. G. Datsios, D. G. Patsalis, P. Mikropoulos, T. Tsovilis
This work investigates with the aid of ATP- EMTP simulations the effects of lightning current waveform on the computed fast-front overvoltages and critical currents causing insulation flashover to a typical 150 kV overhead transmission line. First return-strokes of negative and positive downward lightning flashes are considered for shielding failure flashover and backflashover cases. The CIGRE current waveform is employed in simulations; recorded lightning current waveforms are used as well. The front time, maximum steepness, and time to half value are varied taking into account their statistical distributions. It is shown that the representation of lightning current affects considerably the waveform of the arising fast-front overvoltages and consequently the minimum currents causing flashover. The effects of waveform parameters are quantified and discussed for the 150 kV line under study.
{"title":"Effects of Lightning Current Waveform on the Fast-Front Overvoltages and Critical Currents Causing Insulation Flashover to a 150 kV Overhead Transmission Line","authors":"Z. G. Datsios, D. G. Patsalis, P. Mikropoulos, T. Tsovilis","doi":"10.1109/ICLP56858.2022.9942612","DOIUrl":"https://doi.org/10.1109/ICLP56858.2022.9942612","url":null,"abstract":"This work investigates with the aid of ATP- EMTP simulations the effects of lightning current waveform on the computed fast-front overvoltages and critical currents causing insulation flashover to a typical 150 kV overhead transmission line. First return-strokes of negative and positive downward lightning flashes are considered for shielding failure flashover and backflashover cases. The CIGRE current waveform is employed in simulations; recorded lightning current waveforms are used as well. The front time, maximum steepness, and time to half value are varied taking into account their statistical distributions. It is shown that the representation of lightning current affects considerably the waveform of the arising fast-front overvoltages and consequently the minimum currents causing flashover. The effects of waveform parameters are quantified and discussed for the 150 kV line under study.","PeriodicalId":403323,"journal":{"name":"2022 36th International Conference on Lightning Protection (ICLP)","volume":"42 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123597853","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-10-02DOI: 10.1109/ICLP56858.2022.9942590
Ndiadia Kandolo Emmanuel, Rostha Loha Paulo, Tondozi Keto Francois, Tshitenge Mbuebue Jean Marie, Kayembe Kalombo Jean Claude, Phuku Phuati Edmond
The paper examines the reciprocal relationships between lightning activity (number of lightning flashes) and convective rain of mesoscale convective systems in the Equatorial African region and quantify them. The results of this study include: The dependence of lightning activity on convective rain varies from one region to another, as shown by correlation or coherence wavelet studies. The relationship between lightning activity and convective rain has a linear character in the two sub-regions of Equatorial Africa; a very good positive and significant correlation for both the North region $boldsymbol{(mathrm{R}=0.899)}$ and the South one $boldsymbol{(mathrm{R}=0.934)}$ of Equatorial Africa. This correlation is even stronger in the South region than in the North region of Equatorial Africa, although the electric activity is much more important in the North than in the South. The two models thus established are very well suited to both the “number of lightning flashes and convective rain” data of one or the other sub-region and explains 81 % (resp. 85 %) of the variability of the response data around the mean, in the North (resp. South) of Equatorial Africa. Number of lightning flashes and convective rain show very high trends in both sub-regions and are in an average ratio of about 94297:1 and 93102:1 (flashes/mm), respectively in the north region and in the south one of Equatorial Africa. This reveals the approximately invariant nature of the relationship between lightning activity and convective rain, both locally and globally. Similarly, the degree of linearity between the two signals $mathbf{S}_{1}$, lightning activity and $mathbf{S}_{2}$, convective rain in the Equatorial African region, both in the North and in the South, has been characterized (linear correlation level between 0 and 1) for any time-scale location and shows that the interactions between the two signals are at sub-annual and seasonal scales, with a relative phase difference of 0° (in phase).
{"title":"Study of the correlation between lightning activity and convective rain over Equatorial Africa","authors":"Ndiadia Kandolo Emmanuel, Rostha Loha Paulo, Tondozi Keto Francois, Tshitenge Mbuebue Jean Marie, Kayembe Kalombo Jean Claude, Phuku Phuati Edmond","doi":"10.1109/ICLP56858.2022.9942590","DOIUrl":"https://doi.org/10.1109/ICLP56858.2022.9942590","url":null,"abstract":"The paper examines the reciprocal relationships between lightning activity (number of lightning flashes) and convective rain of mesoscale convective systems in the Equatorial African region and quantify them. The results of this study include: The dependence of lightning activity on convective rain varies from one region to another, as shown by correlation or coherence wavelet studies. The relationship between lightning activity and convective rain has a linear character in the two sub-regions of Equatorial Africa; a very good positive and significant correlation for both the North region $boldsymbol{(mathrm{R}=0.899)}$ and the South one $boldsymbol{(mathrm{R}=0.934)}$ of Equatorial Africa. This correlation is even stronger in the South region than in the North region of Equatorial Africa, although the electric activity is much more important in the North than in the South. The two models thus established are very well suited to both the “number of lightning flashes and convective rain” data of one or the other sub-region and explains 81 % (resp. 85 %) of the variability of the response data around the mean, in the North (resp. South) of Equatorial Africa. Number of lightning flashes and convective rain show very high trends in both sub-regions and are in an average ratio of about 94297:1 and 93102:1 (flashes/mm), respectively in the north region and in the south one of Equatorial Africa. This reveals the approximately invariant nature of the relationship between lightning activity and convective rain, both locally and globally. Similarly, the degree of linearity between the two signals $mathbf{S}_{1}$, lightning activity and $mathbf{S}_{2}$, convective rain in the Equatorial African region, both in the North and in the South, has been characterized (linear correlation level between 0 and 1) for any time-scale location and shows that the interactions between the two signals are at sub-annual and seasonal scales, with a relative phase difference of 0° (in phase).","PeriodicalId":403323,"journal":{"name":"2022 36th International Conference on Lightning Protection (ICLP)","volume":"23 4","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120870888","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-10-02DOI: 10.1109/ICLP56858.2022.9942643
Martin Hannig, R. Brocke
When lightning strikes an outer lightning protection system, hazardous touch voltages may occur. The lightning strike itself can be composed of different current wave shapes, which are directly connected to the first and subsequent return strokes. These current impulses have different characteristics. The resulting touch voltage wave shape is related to two of those characteristics. One characteristic is the magnitude of the current. The touch voltage wave shape is linked proportionally to the current wave shape flowing to ground. The second characteristic is the steepness of the current impulse. The rate of current rise induces a touch voltage in the loop, formed by the human body, the down conductor and the ground. In case of lightning strike, limits for those voltages are not defined. In order to evaluate the threat for a human being regarding touch voltages, limits must be known. The main threat comes from the ventricular fibrillation of the heart. Standards define relations between current magnitude and duration or energies that can be handled by a human body. However, it is not clear how much current is drained through the human heart, when voltages get steeper and shorter in duration. A computer simulation of a human body is conducted to compare known integral electrical parameters with parameters from the literature. From these findings, limits on hazardous touch voltages are derived. The main focus lies on the energy consumption of the human body and the related energy turnover in the human heart as an integral value.
{"title":"Numerical Simulation of Permissible Touch Voltages in Case of a Lightning Incidence","authors":"Martin Hannig, R. Brocke","doi":"10.1109/ICLP56858.2022.9942643","DOIUrl":"https://doi.org/10.1109/ICLP56858.2022.9942643","url":null,"abstract":"When lightning strikes an outer lightning protection system, hazardous touch voltages may occur. The lightning strike itself can be composed of different current wave shapes, which are directly connected to the first and subsequent return strokes. These current impulses have different characteristics. The resulting touch voltage wave shape is related to two of those characteristics. One characteristic is the magnitude of the current. The touch voltage wave shape is linked proportionally to the current wave shape flowing to ground. The second characteristic is the steepness of the current impulse. The rate of current rise induces a touch voltage in the loop, formed by the human body, the down conductor and the ground. In case of lightning strike, limits for those voltages are not defined. In order to evaluate the threat for a human being regarding touch voltages, limits must be known. The main threat comes from the ventricular fibrillation of the heart. Standards define relations between current magnitude and duration or energies that can be handled by a human body. However, it is not clear how much current is drained through the human heart, when voltages get steeper and shorter in duration. A computer simulation of a human body is conducted to compare known integral electrical parameters with parameters from the literature. From these findings, limits on hazardous touch voltages are derived. The main focus lies on the energy consumption of the human body and the related energy turnover in the human heart as an integral value.","PeriodicalId":403323,"journal":{"name":"2022 36th International Conference on Lightning Protection (ICLP)","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124432957","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-10-02DOI: 10.1109/ICLP56858.2022.9942507
Christian Drebenstedt, S. Jugelt, M. Rock
The rising amount of self sufficient DC systems for generating, storing, distributing and using electrical energy requires new surge protective devices due to the requirements arising from direct-current application. The development of such new devices demands commonly applicable and reproducible surge and line follow current pulses to reproduce typical fault current situations and to evaluate voltage and current limiting capabilities. In this paper, we present a test circuit for 10/350 μs lightning current with a possible superposition of line follow high-voltage direct-current. For this, we utilize an existing lightning current test system and present necessary modifications to create a line-pulser pulse forming network (PFN). With this, we are able to provide pulses of direct-current up to 1.2 kA at test voltages up to 6 kV with a pulse duration in the range of 2 ms to 25 ms. Furthermore, a combination of PFN und lightning current discharge is possible and presented here. With this new type of stress test, we first evaluated selected up to date spark gap-based lightning current arresters in terms of their direct-current limiting capability and current handling for combined direct-current and lightning current wave shapes. The results show a significant influence of the direct-current level and lightning current amplitude on the current limiting and interruption characteristics.
{"title":"Test circuit for evaluation of physical characteristics of SPDs with combined DC and impulse load","authors":"Christian Drebenstedt, S. Jugelt, M. Rock","doi":"10.1109/ICLP56858.2022.9942507","DOIUrl":"https://doi.org/10.1109/ICLP56858.2022.9942507","url":null,"abstract":"The rising amount of self sufficient DC systems for generating, storing, distributing and using electrical energy requires new surge protective devices due to the requirements arising from direct-current application. The development of such new devices demands commonly applicable and reproducible surge and line follow current pulses to reproduce typical fault current situations and to evaluate voltage and current limiting capabilities. In this paper, we present a test circuit for 10/350 μs lightning current with a possible superposition of line follow high-voltage direct-current. For this, we utilize an existing lightning current test system and present necessary modifications to create a line-pulser pulse forming network (PFN). With this, we are able to provide pulses of direct-current up to 1.2 kA at test voltages up to 6 kV with a pulse duration in the range of 2 ms to 25 ms. Furthermore, a combination of PFN und lightning current discharge is possible and presented here. With this new type of stress test, we first evaluated selected up to date spark gap-based lightning current arresters in terms of their direct-current limiting capability and current handling for combined direct-current and lightning current wave shapes. The results show a significant influence of the direct-current level and lightning current amplitude on the current limiting and interruption characteristics.","PeriodicalId":403323,"journal":{"name":"2022 36th International Conference on Lightning Protection (ICLP)","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127746942","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-10-02DOI: 10.1109/ICLP56858.2022.9942647
Binghao Li, Jinqiang He, Y. Liao, Hao Li, Hao Pan, Yeqiang Deng
Thunderstorms are among the most damaging weather events. Selecting an appropriate statistical method based on the lightning location system is an effective way to estimate lightning parameters, and so as to propose lightning protection schemes. In this paper, theory, calculation efficiency and computational accuracy of two typical statistical methods are summarized and reviewed. The performances of these two methods in different landforms and with/without transmission line towers are compared. It is found that for a large statistical region, adopting the improved grid statistic method can improve the calculation efficiency without compromising accuracy. For regions with noticeable terrain difference, the circular domain statistic method is a better choice. Selecting 1 km as the radius of the statistical area is appropriate to fully reveal the difference of lightning parameters in different terrain, and to meet the accuracy requirements at the same time.
{"title":"A Research on Cloud-to-Ground Lightning Statistical Methods Based on LLS","authors":"Binghao Li, Jinqiang He, Y. Liao, Hao Li, Hao Pan, Yeqiang Deng","doi":"10.1109/ICLP56858.2022.9942647","DOIUrl":"https://doi.org/10.1109/ICLP56858.2022.9942647","url":null,"abstract":"Thunderstorms are among the most damaging weather events. Selecting an appropriate statistical method based on the lightning location system is an effective way to estimate lightning parameters, and so as to propose lightning protection schemes. In this paper, theory, calculation efficiency and computational accuracy of two typical statistical methods are summarized and reviewed. The performances of these two methods in different landforms and with/without transmission line towers are compared. It is found that for a large statistical region, adopting the improved grid statistic method can improve the calculation efficiency without compromising accuracy. For regions with noticeable terrain difference, the circular domain statistic method is a better choice. Selecting 1 km as the radius of the statistical area is appropriate to fully reveal the difference of lightning parameters in different terrain, and to meet the accuracy requirements at the same time.","PeriodicalId":403323,"journal":{"name":"2022 36th International Conference on Lightning Protection (ICLP)","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125598629","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-10-02DOI: 10.1109/ICLP56858.2022.9942523
C. Mata, J. D. Hill
Charge Transfer Systems (CTS) are non-conventional lightning protection devices that, according to vendor specifications, prevent lightning from terminating within a defined area. The devices have been installed at facilities around the world in lieu of traditional Franklin rod lightning protection systems. Two prominent CTS installations in the United States are at the Browns Ferry Nuclear Plant and the Memphis FedEx World Hub. Historical NLDN data from 1995-2019 are analyzed for these two sites to illustrate whether the vendor claims of lightning prevention are, in fact, accurate. Ground-stroke densities are computed in areas where CTS are installed versus those without CTS to determine if there is a statistically significant difference that could be attributed to DAS installation.
{"title":"Performance Evaluation of Non-Conventional Lightning Protection Systems Based on NLDN Data","authors":"C. Mata, J. D. Hill","doi":"10.1109/ICLP56858.2022.9942523","DOIUrl":"https://doi.org/10.1109/ICLP56858.2022.9942523","url":null,"abstract":"Charge Transfer Systems (CTS) are non-conventional lightning protection devices that, according to vendor specifications, prevent lightning from terminating within a defined area. The devices have been installed at facilities around the world in lieu of traditional Franklin rod lightning protection systems. Two prominent CTS installations in the United States are at the Browns Ferry Nuclear Plant and the Memphis FedEx World Hub. Historical NLDN data from 1995-2019 are analyzed for these two sites to illustrate whether the vendor claims of lightning prevention are, in fact, accurate. Ground-stroke densities are computed in areas where CTS are installed versus those without CTS to determine if there is a statistically significant difference that could be attributed to DAS installation.","PeriodicalId":403323,"journal":{"name":"2022 36th International Conference on Lightning Protection (ICLP)","volume":"70 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115790513","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-10-02DOI: 10.1109/ICLP56858.2022.9942538
Noor Ui Ain, F. Mahmood, Amna Shaukat, Mohammad E. M. Rizk
The modeling of a lightning return stroke is the most widely discussed topic in the domain of electromagnetic compatibility. In this article, we present a comparative analysis of various engineering return stroke models, namely, transmission line type and travelling current source type models, respectively, on lightning-induced overvoltages over a lossy ground. These models describe the spatial and temporal distribution of the lightning return-stroke current along the lightning channel. A sum of Heidler functions is adopted to characterize the lightning return-stroke current. The finite-difference time-domain approach is used to compute the electromagnetic fields for a finitely conducting ground. Then Agrawal's coupling model is adopted to compute the incident and the scattered components of the voltages and correspondingly their resultant, that is, lightning-induced overvoltages. The impact of these models is analyzed on peak values, rise-time, and the decay characteristics of lightning-induced overvoltages for various ground configurations.
{"title":"Evaluation of Ground Parameters on Lightning-Induced Over-Voltages Considering Various Return Stroke Models","authors":"Noor Ui Ain, F. Mahmood, Amna Shaukat, Mohammad E. M. Rizk","doi":"10.1109/ICLP56858.2022.9942538","DOIUrl":"https://doi.org/10.1109/ICLP56858.2022.9942538","url":null,"abstract":"The modeling of a lightning return stroke is the most widely discussed topic in the domain of electromagnetic compatibility. In this article, we present a comparative analysis of various engineering return stroke models, namely, transmission line type and travelling current source type models, respectively, on lightning-induced overvoltages over a lossy ground. These models describe the spatial and temporal distribution of the lightning return-stroke current along the lightning channel. A sum of Heidler functions is adopted to characterize the lightning return-stroke current. The finite-difference time-domain approach is used to compute the electromagnetic fields for a finitely conducting ground. Then Agrawal's coupling model is adopted to compute the incident and the scattered components of the voltages and correspondingly their resultant, that is, lightning-induced overvoltages. The impact of these models is analyzed on peak values, rise-time, and the decay characteristics of lightning-induced overvoltages for various ground configurations.","PeriodicalId":403323,"journal":{"name":"2022 36th International Conference on Lightning Protection (ICLP)","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131125825","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-10-02DOI: 10.1109/ICLP56858.2022.9942500
A. Leal, Wendler L. N. Matos
Lightning occurrence is a real threat to human beings and animals over the Amazon region. Lightning is also responsible for economic losses in electric, telecommunication, and other sectors, but its prediction remains a challenging task. Lightning prediction can contribute to minimizing the risks and losses caused by this natural phenomenon. In this work, we have used data from ground-based weather stations, including air temperature, humidity, pressure, and wind speed to predict lightning occurrence within one hour. Forecasts are made for a region up to about 30 km from each of the nine capital cities of the nine states of the Legal Amazon region in Brazil. We use GLD360 data to validate predictions and train the machine learning algorithm. We used a database of 6 years of observation (2015 to 2020) to test and validate the prediction models. The model for Belém - Pará showed the highest F1-Score, 0.34, and the highest Area Under the ROC Curve, 0.836. Overall, the accuracy of the models for each city is higher than 71%. This approach can be used in regions of the Amazon in which only ground-based weather station data is available.
{"title":"Short-term lightning prediction in the Amazon region using ground-based weather station data and machine learning techniques","authors":"A. Leal, Wendler L. N. Matos","doi":"10.1109/ICLP56858.2022.9942500","DOIUrl":"https://doi.org/10.1109/ICLP56858.2022.9942500","url":null,"abstract":"Lightning occurrence is a real threat to human beings and animals over the Amazon region. Lightning is also responsible for economic losses in electric, telecommunication, and other sectors, but its prediction remains a challenging task. Lightning prediction can contribute to minimizing the risks and losses caused by this natural phenomenon. In this work, we have used data from ground-based weather stations, including air temperature, humidity, pressure, and wind speed to predict lightning occurrence within one hour. Forecasts are made for a region up to about 30 km from each of the nine capital cities of the nine states of the Legal Amazon region in Brazil. We use GLD360 data to validate predictions and train the machine learning algorithm. We used a database of 6 years of observation (2015 to 2020) to test and validate the prediction models. The model for Belém - Pará showed the highest F1-Score, 0.34, and the highest Area Under the ROC Curve, 0.836. Overall, the accuracy of the models for each city is higher than 71%. This approach can be used in regions of the Amazon in which only ground-based weather station data is available.","PeriodicalId":403323,"journal":{"name":"2022 36th International Conference on Lightning Protection (ICLP)","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124438973","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-10-02DOI: 10.1109/ICLP56858.2022.9942529
Sanele Gcaba, Hugh G. P. Hunt
South Africa's flash density map is derived from an IEC 62858 compliant Lightning Location System (LLS) known as the Southern African Lightning Detection Network (SALDN) owned and operated by the South African Weather Service (SAWS). The Ground Flash Density (GFD) parameter has been widely used to depict the lightning risk across the country to inform effective lightning protection. However, the spatial and temporal flash clustering technique characterises a flash consisting of multiple strokes with only the parameters of the first return stroke and therefore assumes a single Ground Strike Point (GSP) per flash. The GFD parameter thus does not account for possible multiple GSPs per flash as evident from ground-truth data in a form of high speed camera observations. The GFD parameter may therefore be underestimating the amount of lightning risk. This paper proposes a new South African GSP density map, using the same lightning dataset from the IEC 62858 compliant SALDN to estimate the associated lightning risk. The GSP parameter and consequently the GSP map is derived from a GSP clustering algorithm with a proven success rate of upto 90%. In this paper, the GFD has been derived from SALDN data between July 2007 and July 2016, the GSPs have been estimated using a GSP clusturing algorithm in MATLAB ®, where strokes of a flash within 150 m and overlapping error ellipses form a GSP. The results show a mean of 1.81 GSPs per flash with the highest difference between GFD and GSPs depicted around the high altitude areas of Mpumalanga and Kwazulu Natal provinces.
{"title":"Ground Strike Point Density Map of South Africa","authors":"Sanele Gcaba, Hugh G. P. Hunt","doi":"10.1109/ICLP56858.2022.9942529","DOIUrl":"https://doi.org/10.1109/ICLP56858.2022.9942529","url":null,"abstract":"South Africa's flash density map is derived from an IEC 62858 compliant Lightning Location System (LLS) known as the Southern African Lightning Detection Network (SALDN) owned and operated by the South African Weather Service (SAWS). The Ground Flash Density (GFD) parameter has been widely used to depict the lightning risk across the country to inform effective lightning protection. However, the spatial and temporal flash clustering technique characterises a flash consisting of multiple strokes with only the parameters of the first return stroke and therefore assumes a single Ground Strike Point (GSP) per flash. The GFD parameter thus does not account for possible multiple GSPs per flash as evident from ground-truth data in a form of high speed camera observations. The GFD parameter may therefore be underestimating the amount of lightning risk. This paper proposes a new South African GSP density map, using the same lightning dataset from the IEC 62858 compliant SALDN to estimate the associated lightning risk. The GSP parameter and consequently the GSP map is derived from a GSP clustering algorithm with a proven success rate of upto 90%. In this paper, the GFD has been derived from SALDN data between July 2007 and July 2016, the GSPs have been estimated using a GSP clusturing algorithm in MATLAB ®, where strokes of a flash within 150 m and overlapping error ellipses form a GSP. The results show a mean of 1.81 GSPs per flash with the highest difference between GFD and GSPs depicted around the high altitude areas of Mpumalanga and Kwazulu Natal provinces.","PeriodicalId":403323,"journal":{"name":"2022 36th International Conference on Lightning Protection (ICLP)","volume":"56 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116459158","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-10-02DOI: 10.1109/ICLP56858.2022.9942579
P. H. Pretorius
IEEE Std 1692 (2011) states that one of the categories that cover electrical equipment damage from lightning is lack of protection against ground potential rise. In the experience of the author, the threat of lightning ground potential rise to sensitive electronic equipment, appears to be overlooked in many cases, particularly in the case of some large utility scale photovoltaic plant. It is worth noting that the concept of earth potential rise or ground potential rise is not mentioned once in the nearly 400 odd pages of the 4 Part IEC 62305 lightning protection standard. In this paper, i) specific comments are raised about anticipated lightning ground potential rise levels and ground potential difference levels, in the context of large utility scale photovoltaic plant; ii) awareness is raised about lightning ground potential rise (GPR) and its threat to sensitive electronic communication equipment, particularly in large utility scale PV plant and iii) the recommendation is made to include an Addendum, making reference to lightning ground potential rise, in the next addition of the IEC 62305 standard. The paper also points out the implication of introducing surge protective devices (SPDs) to wire-line communication systems, such as, an RS 485 system. In such cases, reverse operation of the SPDs under lightning GPR, may result in extended damage. The latter is particularly important to large utility scale PV plant in view of the high number of components present at these locations.
{"title":"On Lightning Ground Potential Rise and Wire- Line Communications in Large Utility Scale PV Plant","authors":"P. H. Pretorius","doi":"10.1109/ICLP56858.2022.9942579","DOIUrl":"https://doi.org/10.1109/ICLP56858.2022.9942579","url":null,"abstract":"IEEE Std 1692 (2011) states that one of the categories that cover electrical equipment damage from lightning is lack of protection against ground potential rise. In the experience of the author, the threat of lightning ground potential rise to sensitive electronic equipment, appears to be overlooked in many cases, particularly in the case of some large utility scale photovoltaic plant. It is worth noting that the concept of earth potential rise or ground potential rise is not mentioned once in the nearly 400 odd pages of the 4 Part IEC 62305 lightning protection standard. In this paper, i) specific comments are raised about anticipated lightning ground potential rise levels and ground potential difference levels, in the context of large utility scale photovoltaic plant; ii) awareness is raised about lightning ground potential rise (GPR) and its threat to sensitive electronic communication equipment, particularly in large utility scale PV plant and iii) the recommendation is made to include an Addendum, making reference to lightning ground potential rise, in the next addition of the IEC 62305 standard. The paper also points out the implication of introducing surge protective devices (SPDs) to wire-line communication systems, such as, an RS 485 system. In such cases, reverse operation of the SPDs under lightning GPR, may result in extended damage. The latter is particularly important to large utility scale PV plant in view of the high number of components present at these locations.","PeriodicalId":403323,"journal":{"name":"2022 36th International Conference on Lightning Protection (ICLP)","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123997331","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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