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The purpose of this work is to process lightning data from the Swedish Meteorological and Hydrological Institutes (SMHI) lightning location system to analyze which currents occur during lightning strikes in Sweden. The result can then be compared with the values currently used in dimensioning lightning protection for the transmission network, to evaluate whether the design of the protection is relevant with regard to the currents registered by the lightning location system. The results based on the years 2015-2020 show that the current distribution fits a lognormal and generalized extreme value distribution, the latter yielding a slightly better representation. The national analysis shows a significantly lower median peak current in Sweden compared to the reference median peak current recommended by CIGRE.

The streamer bursts generated during the initiation and propagation of leaders play an important role in the creation and maintenance of hot discharge channels in air. The most important parameters related to streamer bursts in this respect are the length of the streamer bursts, their lateral extent and the charge associated with them. The lateral extent of the streamer bursts may play a significant role in deciding the path and the tortuosity of the discharge channels of laboratory discharges and lightning. The charges associated with the streamer bursts are needed in understanding the physical processes associated with the streamer-to-leader transition. In this paper, the length, the lateral extension and the charge of the streamer regions generated by grounded conductors when exposed to external electric fields are estimated. This estimation is based on two assumptions: (i) once a streamer is incepted, the streamer head follows the direction of maximum background electric field at the location of the streamer head and (ii) the streamer continues to extend along this direction until the potential drop along the streamer channel matches the potential drop caused by the background electric field between the initial and end points of the streamer channel. The same technique could be used to estimate the streamer bursts generated in laboratory discharges and lightning stepped leaders. It is shown that in estimating the geometry of the streamer region, it is necessary to include the spread of streamers caused by branching. Moreover, the charge associated with the streamer region increases as the frequency of branching increases. The results obtained confirm that the charge in the streamer region can significantly change the potential ahead of the streamer region from the background potential and this has to be taken into account in any study that simulates the initiation and propagation of lightning leaders. Since the streamer bursts of leaders control the direction an

The streamer bursts generated during the initiation and propagation of leaders play an important role in the creation and maintenance of hot discharge channels in air. The most important parameters related to streamer bursts in this respect are the length of the streamer bursts, their lateral extent and the charge associated with them. The lateral extent of the streamer bursts may play a significant role in deciding the path and the tortuosity of the discharge channels of laboratory discharges and lightning. The charges associated with the streamer bursts are needed in understanding the physical processes associated with the streamer-to-leader transition. In this paper, the length, the lateral extension and the charge of the streamer regions generated by grounded conductors when exposed to external electric fields are estimated. This estimation is based on two assumptions: (i) once a streamer is incepted, the streamer head follows the direction of maximum background electric field at the location of the streamer head and (ii) the streamer continues to extend along this direction until the potential drop along the streamer channel matches the potential drop caused by the background electric field between the initial and end points of the streamer channel. The same technique could be used to estimate the streamer bursts generated in laboratory discharges and lightning stepped leaders. It is shown that in estimating the geometry of the streamer region, it is necessary to include the spread of streamers caused by branching. Moreover, the charge associated with the streamer region increases as the frequency of branching increases. The results obtained confirm that the charge in the streamer region can significantly change the potential ahead of the streamer region from the background potential and this has to be taken into account in any study that simulates the initiation and propagation of lightning leaders. Since the streamer bursts of leaders control the direction an

Data from the lightning detection system owned by SMHI mainly from 2015-2020 was used to model the peak current. The log-normal distribution and the generalised extreme value distribution were tried and the later was slightly better. The median of the peak current was found to be lower than the value recommended by Cigre, in particular for the first stroke in a flash. In part, this can be due that the lightning detection system is calibrated for the subsequent negative strokes. The duration and the interval of the strokes were as expected. No correlation between current and rise time was found, whereas there were some differences between the regions in Sweden.

The streamer bursts generated during the initiation and propagation of leaders play an important role in the creation and maintenance of hot discharge channels in air. The most important parameters related to streamer bursts in this respect are the length of the streamer bursts, their lateral extent and the charge associated with them. The lateral extent of the streamer bursts may play a significant role in deciding the path and the tortuosity of the discharge channels of laboratory discharges and lightning. The charges associated with the streamer bursts are needed in understanding the physical processes associated with the streamer-to-leader transition. In this paper, the length, the lateral extension and the charge of the streamer regions generated by grounded conductors when exposed to external electric fields are estimated. This estimation is based on two assumptions: (i) once a streamer is incepted, the streamer head follows the direction of maximum background electric field at the location of the streamer head and (ii) the streamer continues to extend along this direction until the potential drop along the streamer channel matches the potential drop caused by the background electric field between the initial and end points of the streamer channel. The same technique could be used to estimate the streamer bursts generated in laboratory discharges and lightning stepped leaders. It is shown that in estimating the geometry of the streamer region, it is necessary to include the spread of streamers caused by branching. Moreover, the charge associated with the streamer region increases as the frequency of branching increases. The results obtained confirm that the charge in the streamer region can significantly change the potential ahead of the streamer region from the background potential and this has to be taken into account in any study that simulates the initiation and propagation of lightning leaders. Since the streamer bursts of leaders control the direction an

The streamer bursts generated during the initiation and propagation of leaders play an important role in the creation and maintenance of hot discharge channels in air. The most important parameters related to streamer bursts in this respect are the length of the streamer bursts, their lateral extent and the charge associated with them. The lateral extent of the streamer bursts may play a significant role in deciding the path and the tortuosity of the discharge channels of laboratory discharges and lightning. The charges associated with the streamer bursts are needed in understanding the physical processes associated with the streamer-to-leader transition. In this paper, the length, the lateral extension and the charge of the streamer regions generated by grounded conductors when exposed to external electric fields are estimated. This estimation is based on two assumptions: (i) once a streamer is incepted, the streamer head follows the direction of maximum background electric field at the location of the streamer head and (ii) the streamer continues to extend along this direction until the potential drop along the streamer channel matches the potential drop caused by the background electric field between the initial and end points of the streamer channel. The same technique could be used to estimate the streamer bursts generated in laboratory discharges and lightning stepped leaders. It is shown that in estimating the geometry of the streamer region, it is necessary to include the spread of streamers caused by branching. Moreover, the charge associated with the streamer region increases as the frequency of branching increases. The results obtained confirm that the charge in the streamer region can significantly change the potential ahead of the streamer region from the background potential and this has to be taken into account in any study that simulates the initiation and propagation of lightning leaders. Since the streamer bursts of leaders control the direction an

The streamer bursts generated during the initiation and propagation of leaders play an important role in the creation and maintenance of hot discharge channels in air. The most important parameters related to streamer bursts in this respect are the length of the streamer bursts, their lateral extent and the charge associated with them. The lateral extent of the streamer bursts may play a significant role in deciding the path and the tortuosity of the discharge channels of laboratory discharges and lightning. The charges associated with the streamer bursts are needed in understanding the physical processes associated with the streamer-to-leader transition. In this paper, the length, the lateral extension and the charge of the streamer regions generated by grounded conductors when exposed to external electric fields are estimated. This estimation is based on two assumptions: (i) once a streamer is incepted, the streamer head follows the direction of maximum background electric field at the location of the streamer head and (ii) the streamer continues to extend along this direction until the potential drop along the streamer channel matches the potential drop caused by the background electric field between the initial and end points of the streamer channel. The same technique could be used to estimate the streamer bursts generated in laboratory discharges and lightning stepped leaders. It is shown that in estimating the geometry of the streamer region, it is necessary to include the spread of streamers caused by branching. Moreover, the charge associated with the streamer region increases as the frequency of branching increases. The results obtained confirm that the charge in the streamer region can significantly change the potential ahead of the streamer region from the background potential and this has to be taken into account in any study that simulates the initiation and propagation of lightning leaders. Since the streamer bursts of leaders control the direction an

[ES] El presente proyecto tiene por objeto especificar las características técnicas, constructivas y económicas de la instalación eléctrica, protección contra el rayo, instalación fotovoltaica e instalaciones especiales, de un hotel de 4 estrellas de nueva planta situado en Málaga. La instalación eléctrica se diseña partiendo de la necesidad de suministro en alta tensión al complejo hotelero, debido a la potencia instalada en el mismo. Por tanto, será necesario disponer de un centro de seccionamiento independiente y un centro de transformación de abonado, desde el cual se dará suministro en baja tensión al complejo. También se estudia la necesidad de un sistema de protección contra el rayo situado en cubierta, el cual debe ser capaz de minimizar los efectos destructivos de las descargas atmosféricas. Con la finalidad de cumplir con el documento básico de ahorro de energía, se estudia la implantación de un sistema de generación fotovoltaica situado en cubierta, cuya disposición estará supeditada al propio volumen de la cubierta y los elementos dispuestos en la misma. Por otra parte, se presenta un estudio de las instalaciones especiales del hotel, las cuales constarán del sistema de protección contra incendios (formado por sistema de detección, alarma, instalación de BIEs y extintores), así como las características básicas del sistema de voz-datos, radio, televisión, anti-intrusión y videoportero. Finalmente, se presenta el coste económico de dichas instalaciones, las cuales se han dividido en diferentes subproyectos para una mejor comprensión de estas. Con dicho proyecto y el resto de los documentos preceptivos ante los servicios territoriales de industria, quedará en disposición para su ocupación y explotación., [EN] The purpose of this project is to specify the technical, constructive and economic characteristics of the electrical installation, lightning protection, photovoltaic installation and special installations for a new 4-star hotel located in Malaga. The electrical installation is designed on the basis of the need for high voltage supply to the hotel complex, due to the power installed in it. Therefore, it will be necessary to have an independent switching centre and a subscriber transformation centre, from which the complex will be supplied at low voltage. The need for a lightning protection system located on the roof, which must be capable of minimising the destructive effects of atmospheric discharges, is also being studied. In order to comply with the basic energy saving document, the implementation of a photovoltaic generation system located on the roof is studied, the layout of which will depend on the volume of the roof and the elements on it. On the other hand, a study of the special installations of the hotel is presented, which will consist of the fire protection system (consisting of a detection system, alarm, installation of FHE and extinguishers), as well as the basic characteristics of the voice-data system, radio, television, anti-intrusion and video door entry system. Finally, the economic cost of these installations is presented, which have been divided into different subprojects for a better understanding of them. With this project and the rest of the documents required by the territorial industry services, it will be ready for occupation and operation.

[ES] El presente proyecto tiene por objeto especificar las características técnicas, constructivas y económicas de la instalación eléctrica, protección contra el rayo, instalación fotovoltaica e instalaciones especiales, de un hotel de 4 estrellas de nueva planta situado en Málaga. La instalación eléctrica se diseña partiendo de la necesidad de suministro en alta tensión al complejo hotelero, debido a la potencia instalada en el mismo. Por tanto, será necesario disponer de un centro de seccionamiento independiente y un centro de transformación de abonado, desde el cual se dará suministro en baja tensión al complejo. También se estudia la necesidad de un sistema de protección contra el rayo situado en cubierta, el cual debe ser capaz de minimizar los efectos destructivos de las descargas atmosféricas. Con la finalidad de cumplir con el documento básico de ahorro de energía, se estudia la implantación de un sistema de generación fotovoltaica situado en cubierta, cuya disposición estará supeditada al propio volumen de la cubierta y los elementos dispuestos en la misma. Por otra parte, se presenta un estudio de las instalaciones especiales del hotel, las cuales constarán del sistema de protección contra incendios (formado por sistema de detección, alarma, instalación de BIEs y extintores), así como las características básicas del sistema de voz-datos, radio, televisión, anti-intrusión y videoportero. Finalmente, se presenta el coste económico de dichas instalaciones, las cuales se han dividido en diferentes subproyectos para una mejor comprensión de estas. Con dicho proyecto y el resto de los documentos preceptivos ante los servicios territoriales de industria, quedará en disposición para su ocupación y explotación., [EN] The purpose of this project is to specify the technical, constructive and economic characteristics of the electrical installation, lightning protection, photovoltaic installation and special installations for a new 4-star hotel located in Malaga. The electrical installation is designed on the basis of the need for high voltage supply to the hotel complex, due to the power installed in it. Therefore, it will be necessary to have an independent switching centre and a subscriber transformation centre, from which the complex will be supplied at low voltage. The need for a lightning protection system located on the roof, which must be capable of minimising the destructive effects of atmospheric discharges, is also being studied. In order to comply with the basic energy saving document, the implementation of a photovoltaic generation system located on the roof is studied, the layout of which will depend on the volume of the roof and the elements on it. On the other hand, a study of the special installations of the hotel is presented, which will consist of the fire protection system (consisting of a detection system, alarm, installation of FHE and extinguishers), as well as the basic characteristics of the voice-data system, radio, television, anti-intrusion and video door entry system. Finally, the economic cost of these installations is presented, which have been divided into different subprojects for a better understanding of them. With this project and the rest of the documents required by the territorial industry services, it will be ready for occupation and operation.

[ES] El presente proyecto tiene por objeto especificar las características técnicas, constructivas y económicas de la instalación eléctrica, protección contra el rayo, instalación fotovoltaica e instalaciones especiales, de un hotel de 4 estrellas de nueva planta situado en Málaga. La instalación eléctrica se diseña partiendo de la necesidad de suministro en alta tensión al complejo hotelero, debido a la potencia instalada en el mismo. Por tanto, será necesario disponer de un centro de seccionamiento independiente y un centro de transformación de abonado, desde el cual se dará suministro en baja tensión al complejo. También se estudia la necesidad de un sistema de protección contra el rayo situado en cubierta, el cual debe ser capaz de minimizar los efectos destructivos de las descargas atmosféricas. Con la finalidad de cumplir con el documento básico de ahorro de energía, se estudia la implantación de un sistema de generación fotovoltaica situado en cubierta, cuya disposición estará supeditada al propio volumen de la cubierta y los elementos dispuestos en la misma. Por otra parte, se presenta un estudio de las instalaciones especiales del hotel, las cuales constarán del sistema de protección contra incendios (formado por sistema de detección, alarma, instalación de BIEs y extintores), así como las características básicas del sistema de voz-datos, radio, televisión, anti-intrusión y videoportero. Finalmente, se presenta el coste económico de dichas instalaciones, las cuales se han dividido en diferentes subproyectos para una mejor comprensión de estas. Con dicho proyecto y el resto de los documentos preceptivos ante los servicios territoriales de industria, quedará en disposición para su ocupación y explotación., [EN] The purpose of this project is to specify the technical, constructive and economic characteristics of the electrical installation, lightning protection, photovoltaic installation and special installations for a new 4-star hotel located in Malaga. The electrical installation is designed on the basis of the need for high voltage supply to the hotel complex, due to the power installed in it. Therefore, it will be necessary to have an independent switching centre and a subscriber transformation centre, from which the complex will be supplied at low voltage. The need for a lightning protection system located on the roof, which must be capable of minimising the destructive effects of atmospheric discharges, is also being studied. In order to comply with the basic energy saving document, the implementation of a photovoltaic generation system located on the roof is studied, the layout of which will depend on the volume of the roof and the elements on it. On the other hand, a study of the special installations of the hotel is presented, which will consist of the fire protection system (consisting of a detection system, alarm, installation of FHE and extinguishers), as well as the basic characteristics of the voice-data system, radio, television, anti-intrusion and video door entry system. Finally, the economic cost of these installations is presented, which have been divided into different subprojects for a better understanding of them. With this project and the rest of the documents required by the territorial industry services, it will be ready for occupation and operation.

Despite the significantly large number of deaths and injuries, the property loses and service downtime, lightning is not treated as a serious natural hazard in many countries of which lightning ground flash density is notably high. In this chapter, we highlight this lack of attention from both government and non-governmental sectors as a substantial barrier to curb lightning related losses. The ignorance of experts and statutory bodies that control the implementation of standards and guidelines have paved the way to the flooding of fraudulent products and technologies into the respective countries. The attitudinal issues and negligence of responsibilities of engineering and managerial capacities of both private and government sectors contributes to the mishaps and losses due to lightning-related incidents. The chapter finally discusses possible mechanisms of promoting lightning protection as business ventures in less-privileged communities by developing entrepreneurship among people having low to medium levels of technical know-how., QC 20220421

We investigated features of corona point discharges when a grounded conductive rod is subject to a high background electric field. In the laboratory, high voltage is applied to an upper plate in a plane-to-point experiment, and the discharges are observed from a grounded rod using an ultraviolet camera and a photosensor. The current is measured using a shunt resistor, a current transformer, and a high impedance ammeter. We have found that corona current pulses have fast rise time (tens of nanoseconds) and slow decay (hundreds of nanoseconds). For the initial stage of the discharges, above a certain threshold, the frequency of pulses increases with the voltage applied. In the field, one current sensor coupled to a grounded rod, 1.5 m above a roof, was installed in a site located at an altitude of 2525 m above sea level. The same pulses observed in the laboratory are recorded during periods of electric field enhancement caused by the movement of charged clouds or lightning activity near the sensor. For that specific installation, the frequency of pulses is correlated with the ambient electric field measured 250 meters away. To the best knowledge of the authors, this is the first time in which such correlation is made for outdoor measurements, seeing that other works correlate the electric field with the average current flow. Pulses of positive corona were no longer observed when the electric field magnitude was lower than 1.8 kV/m and pulses of negative corona were more atypical and presented a higher threshold, of about 3.8 kV/m. This study is relevant for understanding the production of corona and space charges in high structures, such as wind turbine blades, towers, and buildings in general., Peer Reviewed, Preprint

Проаналізований сучасний стан грозозахисту ПЛ шляхом розрахунку кількості відключень у рік. Розглянуто ефективність методу фіктивної сфери при проектуванні грозозахисту для ПЛ. Виконано порівняння методу фіктивної сфери , саме для ПЛ, зі стандартним методом захисного кута. Результати, що містяться в магістерській дисертації, мають як теоретичні, так і практичні наслідки і можуть слугувати основою для подальшого детального аналізу грозостійкості ПЛ та обґрунтованого вибору технічних рішень щодо їх захисту від небезпечних впливів блискавок. Аналізуючи результати магістерської дисертації, можна стверджувати, що компактні лінії мають більший захист від впливів блискавки, оскільки підрахунки показали, що для таких ліній характерна менша кількість грозових відключень і, як наслідок, це призведе до зменшення економічних втрат від непланових відключень споживачів, ремонтів та заміни пошкодженого обладнання., The current state of lightning protection of the transmission line is analyzed by counting the number of outages per year. The efficiency of the fictitious sphere method for lightning protection design is considered. The comparison of the fictitious sphere method, namely for the transmission line, with the standard method of the protective angle is performed. The results contained in the master's dissertation have both theoretical and practical consequences and can serve as a basis for further detailed analysis of lightning resistance of overhead lines and a reasonable choice of technical solutions to protect them from the dangerous effects of lightning. Analyzing the results of the master's dissertation, it can be argued that compact lines have greater protection against lightning, as calculations have shown that such lines are characterized by fewer lightning strikes and, consequently, reduce economic losses from unplanned power outages, repairs and replacement. equipment.

Lightning is one of the inevitable disastrous phenomena which in addition to damaging tall edifices, might also consequently endanger humans due to lightning-human interactions. This research focuses on analyzing lightning hazards to humans in the vicinity of heritage monuments in India and Sri Lanka. Five monuments which include three giant stupas namely Ruwanweliseya, Jethawanaramaya and Abayagiriya from Sri Lanka and two large temples namely Brihadishvara Temple and Gangaikonda Cholapuram from India have been chosen for investigation. Lightning-human interaction mechanisms namely direct strike, side flash, aborted upward leader, step and touch voltages have been investigated for the most onerous scenario on humans in the vicinity of the monuments. Firstly, the electro-geometric model as stipulated in standards has been implemented to ascertain the effectiveness of lightning protection to the structures. Subsequently, the study has been extended to the computation of step and touch voltages utilizing lightning current and electrostatic models based on Finite Element Method (FEM) using COMSOL Multi-physics(R). Detailed plots of electric field and voltage distribution of lightning on humans due to a typical lightning current of 30 kA have been obtained. The final study involves assessment of current through humans which is estimated based on lumped R-C human model representation using OrCAD Cadence(R). The analyses reveal that humans are invariably shielded against direct strikes whereas effects due to side flashes are minimal. During strikes to the monuments, high voltage may appear due to step and touch potential under dry conditions, though such effects could be mitigated by appropriate earthing system.

Lightning is one of the inevitable disastrous phenomena which in addition to damaging tall edifices, might also consequently endanger humans due to lightning-human interactions. This research focuses on analyzing lightning hazards to humans in the vicinity of heritage monuments in India and Sri Lanka. Five monuments which include three giant stupas namely Ruwanweliseya, Jethawanaramaya and Abayagiriya from Sri Lanka and two large temples namely Brihadishvara Temple and Gangaikonda Cholapuram from India have been chosen for investigation. Lightning-human interaction mechanisms namely direct strike, side flash, aborted upward leader, step and touch voltages have been investigated for the most onerous scenario on humans in the vicinity of the monuments. Firstly, the electro-geometric model as stipulated in standards has been implemented to ascertain the effectiveness of lightning protection to the structures. Subsequently, the study has been extended to the computation of step and touch voltages utilizing lightning current and electrostatic models based on Finite Element Method (FEM) using COMSOL Multi-physics(R). Detailed plots of electric field and voltage distribution of lightning on humans due to a typical lightning current of 30 kA have been obtained. The final study involves assessment of current through humans which is estimated based on lumped R-C human model representation using OrCAD Cadence(R). The analyses reveal that humans are invariably shielded against direct strikes whereas effects due to side flashes are minimal. During strikes to the monuments, high voltage may appear due to step and touch potential under dry conditions, though such effects could be mitigated by appropriate earthing system.

Lightning is one of the inevitable disastrous phenomena which in addition to damaging tall edifices, might also consequently endanger humans due to lightning-human interactions. This research focuses on analyzing lightning hazards to humans in the vicinity of heritage monuments in India and Sri Lanka. Five monuments which include three giant stupas namely Ruwanweliseya, Jethawanaramaya and Abayagiriya from Sri Lanka and two large temples namely Brihadishvara Temple and Gangaikonda Cholapuram from India have been chosen for investigation. Lightning-human interaction mechanisms namely direct strike, side flash, aborted upward leader, step and touch voltages have been investigated for the most onerous scenario on humans in the vicinity of the monuments. Firstly, the electro-geometric model as stipulated in standards has been implemented to ascertain the effectiveness of lightning protection to the structures. Subsequently, the study has been extended to the computation of step and touch voltages utilizing lightning current and electrostatic models based on Finite Element Method (FEM) using COMSOL Multi-physics(R). Detailed plots of electric field and voltage distribution of lightning on humans due to a typical lightning current of 30 kA have been obtained. The final study involves assessment of current through humans which is estimated based on lumped R-C human model representation using OrCAD Cadence(R). The analyses reveal that humans are invariably shielded against direct strikes whereas effects due to side flashes are minimal. During strikes to the monuments, high voltage may appear due to step and touch potential under dry conditions, though such effects could be mitigated by appropriate earthing system.

Lightning is one of the inevitable disastrous phenomena which in addition to damaging tall edifices, might also consequently endanger humans due to lightning-human interactions. This research focuses on analyzing lightning hazards to humans in the vicinity of heritage monuments in India and Sri Lanka. Five monuments which include three giant stupas namely Ruwanweliseya, Jethawanaramaya and Abayagiriya from Sri Lanka and two large temples namely Brihadishvara Temple and Gangaikonda Cholapuram from India have been chosen for investigation. Lightning-human interaction mechanisms namely direct strike, side flash, aborted upward leader, step and touch voltages have been investigated for the most onerous scenario on humans in the vicinity of the monuments. Firstly, the electro-geometric model as stipulated in standards has been implemented to ascertain the effectiveness of lightning protection to the structures. Subsequently, the study has been extended to the computation of step and touch voltages utilizing lightning current and electrostatic models based on Finite Element Method (FEM) using COMSOL Multi-physics(R). Detailed plots of electric field and voltage distribution of lightning on humans due to a typical lightning current of 30 kA have been obtained. The final study involves assessment of current through humans which is estimated based on lumped R-C human model representation using OrCAD Cadence(R). The analyses reveal that humans are invariably shielded against direct strikes whereas effects due to side flashes are minimal. During strikes to the monuments, high voltage may appear due to step and touch potential under dry conditions, though such effects could be mitigated by appropriate earthing system.

Currently, wind power production is undergoing rapid growth due to the escalating interest in green energy generation. As a result, generators are now choosing to locate wind turbine generators (WTGs) in areas where there is more lightning activity, and earthing problems can be exacerbated further by the soil resistivity being higher than where turbines are usually located. In addition, the desire to capture more energy from the wind has given way to larger WTGs, further increasing the probability of lightning strikes to the structure. This heightened regularity has emphasized the need for an effective grounding system, capable of dissipating the large currents discharged by the lightning into the lightning protection system. This “effective grounding system” must offer a low impedance by limiting the ground potential rise, which is critical due to the wider frequency content of the lightning discharge currents (ranging from DC to several MHz). The design of an effective grounding system for WTGs depends on the calculation of the minimum length of the earth electrodes, soil resistivity and its frequency-dependency, and the impact of WTG foundation. The calculation of the length of earth electrodes needs an accurate measurement of soil resistivity and modeling of the measured resistivity. Hence, this research considers the measured soil resistivity values of an Australian wind farm and presents an analysis of the soil stratification to identify the optimum soil models. The influence of the soil layers on the WTG grounding system is also investigated to install the earth electrodes. As the resistivity of the soil is frequency-dependent, an analysis is performed to evaluate the effect of the frequency-dependent soil parameters on the WTG grounding system at various frequencies of lightning discharge current. In addition, the impact of the rebar of the WTG foundation on the grounding system is evaluated as the rebar shares the lightning discharge currents. The effective

Currently, wind power production is undergoing rapid growth due to the escalating interest in green energy generation. As a result, generators are now choosing to locate wind turbine generators (WTGs) in areas where there is more lightning activity, and earthing problems can be exacerbated further by the soil resistivity being higher than where turbines are usually located. In addition, the desire to capture more energy from the wind has given way to larger WTGs, further increasing the probability of lightning strikes to the structure. This heightened regularity has emphasized the need for an effective grounding system, capable of dissipating the large currents discharged by the lightning into the lightning protection system. This “effective grounding system” must offer a low impedance by limiting the ground potential rise, which is critical due to the wider frequency content of the lightning discharge currents (ranging from DC to several MHz). The design of an effective grounding system for WTGs depends on the calculation of the minimum length of the earth electrodes, soil resistivity and its frequency-dependency, and the impact of WTG foundation. The calculation of the length of earth electrodes needs an accurate measurement of soil resistivity and modeling of the measured resistivity. Hence, this research considers the measured soil resistivity values of an Australian wind farm and presents an analysis of the soil stratification to identify the optimum soil models. The influence of the soil layers on the WTG grounding system is also investigated to install the earth electrodes. As the resistivity of the soil is frequency-dependent, an analysis is performed to evaluate the effect of the frequency-dependent soil parameters on the WTG grounding system at various frequencies of lightning discharge current. In addition, the impact of the rebar of the WTG foundation on the grounding system is evaluated as the rebar shares the lightning discharge currents. The effective

Currently, wind power production is undergoing rapid growth due to the escalating interest in green energy generation. As a result, generators are now choosing to locate wind turbine generators (WTGs) in areas where there is more lightning activity, and earthing problems can be exacerbated further by the soil resistivity being higher than where turbines are usually located. In addition, the desire to capture more energy from the wind has given way to larger WTGs, further increasing the probability of lightning strikes to the structure. This heightened regularity has emphasized the need for an effective grounding system, capable of dissipating the large currents discharged by the lightning into the lightning protection system. This “effective grounding system” must offer a low impedance by limiting the ground potential rise, which is critical due to the wider frequency content of the lightning discharge currents (ranging from DC to several MHz). The design of an effective grounding system for WTGs depends on the calculation of the minimum length of the earth electrodes, soil resistivity and its frequency-dependency, and the impact of WTG foundation. The calculation of the length of earth electrodes needs an accurate measurement of soil resistivity and modeling of the measured resistivity. Hence, this research considers the measured soil resistivity values of an Australian wind farm and presents an analysis of the soil stratification to identify the optimum soil models. The influence of the soil layers on the WTG grounding system is also investigated to install the earth electrodes. As the resistivity of the soil is frequency-dependent, an analysis is performed to evaluate the effect of the frequency-dependent soil parameters on the WTG grounding system at various frequencies of lightning discharge current. In addition, the impact of the rebar of the WTG foundation on the grounding system is evaluated as the rebar shares the lightning discharge currents. The effective

Lightning is one of the inevitable disastrous phenomena which in addition to damaging tall edifices, might also consequently endanger humans due to lightning-human interactions. This research focuses on analyzing lightning hazards to humans in the vicinity of heritage monuments in India and Sri Lanka. Five monuments which include three giant stupas namely Ruwanweliseya, Jethawanaramaya and Abayagiriya from Sri Lanka and two large temples namely Brihadishvara Temple and Gangaikonda Cholapuram from India have been chosen for investigation. Lightning-human interaction mechanisms namely direct strike, side flash, aborted upward leader, step and touch voltages have been investigated for the most onerous scenario on humans in the vicinity of the monuments. Firstly, the electro-geometric model as stipulated in standards has been implemented to ascertain the effectiveness of lightning protection to the structures. Subsequently, the study has been extended to the computation of step and touch voltages utilizing lightning current and electrostatic models based on Finite Element Method (FEM) using COMSOL Multi-physics(R). Detailed plots of electric field and voltage distribution of lightning on humans due to a typical lightning current of 30 kA have been obtained. The final study involves assessment of current through humans which is estimated based on lumped R-C human model representation using OrCAD Cadence(R). The analyses reveal that humans are invariably shielded against direct strikes whereas effects due to side flashes are minimal. During strikes to the monuments, high voltage may appear due to step and touch potential under dry conditions, though such effects could be mitigated by appropriate earthing system.

Магістерська дисертація складається з пояснювальної записки та графічної частини. Пояснювальна записка виконана на 127 сторінках формату А4, яка включає в себе 52 рисунків, 40 таблиць, 34 джерел використаної літератури. Графічна частина містить 8 аркушів технічних креслень форматом А1. В дисертації розглянуто процес формування грозових перенапруг, їх вплив на повітряні лінії електропередавання, а також засоби підвищення грозостійкості електричних мереж. Проведено моделювання варіантів встановлення нелінійних обмежувачів перенапруги на повітряних лініях електро-передавання номінальною напругою 10 кВ при різних випадках розряду блискавки. Сформовано рекомендації щодо вибору оптимальних місць встановлення нелінійних обмежувачів перенапруги для забезпечення захисту електричних мереж від грозових перенапруг., Master’s thesis consists of an explanatory note and graphical part. The explanatory note is made up of 150 pages of A4 format; it includes 129 figures, 15 tables, 25 references. The graphical part contains 8 sheets of A1 format technical drawings. In the thesis the process of formation of lightning overvoltages, their influence on overhead transmission line, as well as means for increasing the lightning resistance of electric networks is considered. Modeling of variants of installation of surge arresters on 10 kV overhead transmission lines for different cases of lightning discharge is carried out. Recommendations on the selection of the optimal sites for installation surge arresters to protect electrical networks from the lightning overvoltages are formulated.

Магістерська дисертація складається з пояснювальної записки та графічної частини. Пояснювальна записка виконана на 113 сторінках формату А4, яка включає в себе 37 рисунків, 59 таблиць, 10 джерел використаної літератури. Графічна частина містить 8 аркушів технічних креслень форматом А1. Дисертація присвячена питанню розрахунків усталених режимів роботи електричної мережі номінальною напругою 110 кВ. Виконано пошук оптимальної конфігурації електричної мережі. Знайдено значення рівнів напруги в незалежних вузлах мережі, потокорозподіл потужності по ділянкам районної мережі, втрати потужності в елементах мережі., Master’s thesis consists of an explanatory note and graphical part. The explanatory note is made up of 113 pages of A4 format; it includes 37 figures, 59 tables, 10 references. The graphical part contains 8 sheets of A1 format technical drawings. The dissertation is devoted to the question of calculations of the established modes of operation of the electrical network with a nominal voltage of 110 kV. Search for the optimal configuration of the electrical network. The values of the voltage levels in the independent nodes of the network, the flow distribution of power in the areas of the district network, the loss of power in the network elements were found.

The Sustainable Energy Development Authority of Malaysia (SEDA) received complaints on damaged components and distribution boards of PV systems due to lightning strikes. Permanent and momentary interruptions on distribution circuits may also occur from the disturbance. In this research, a solar PV Rooftop system (3.91 kWp) given by SEDA is modelled in the PSCAD/EMTDC. The Heidler function is used as lightning current waveform model to analyse the transient current and voltage at two different points under the influence of lightning events. These include different lightning current waveshape, standard lightning current and non-standard lightning current. The effect of the system components when lightning direct strikes at two different points of the installation are examined in this study. The two points lies between the inverter and the solar PV array and between inverter and grid. Extremely high current and voltage due to the direct lightning strike on a certain point at PV Rooftop system are also studied. The results of this case study are observed with the inclusion of surge protective devices (SPDs) and without SPDs. The parameters used were 31 kA peak current, 10 meters length of cable and the lightning impulse current waveshape of 8/20μs. The high current and voltage at P1 striking point are 31 kA and 2397 kV, respectively. As for the AC part, the current and voltage values were found to be 5.97 kA and 5392 kV, respectively. Therefore, SPD with suitable rating provided by SEDA were deployed. Results show that high transient current voltage is expected to clamp sharply at the values of 1.915 kV and 0 A at the P1 striking point. As for the AC part, the current and voltage values were found to be 0 kA and 0.751 V, respectively. Varying lightning impulse current waveshapes at striking point P2 showed that the highest voltage was obtained at waveshape 10/350 μsat 11277 kV followed by waveshapes of 2/70 μs, 8/20 μs and 0.7/6 μs. The high value of transient voltage w

Lightning Surge protection of large structures is done under zonal concept due to the requirement of a system with high current handling capacity and low voltage protection level. Induction of transient voltage in the wiring system within the building is another reason for such. However, in the case of compact structures such as base transmission stations (BTS) of tower sites, outside broadcast vehicles (OBV), various stages of railway systems etc. there are no sufficient lengths in the wiring network for implementing SPDs in such zonal-segment scenario. Also due to the remoteness of most BTSs and need for regular and/or continuous usage of OBVs and railway systems, the time-consuming replacement of outof-order fixed SPDs is most often not warranted. In this backdrop, it was proposed to develop a portable/pluggable system of coordinated SPDs with high current handling capacity and low voltage protection level. A compact SPD system that is capable of handling high currents (50 kA) with low let through voltage (1 kV) was designed using PSCAD and a thorough market research was conducted to identify products that satisfied the requirements of the system designed in PSCAD. Type I and III SPDs capable of handling 50 kA and 2.5 kA respectively, were identified and used for the hardware implementation of the system. Elimination of the type II SPD made the design more compact and better suited for applications at space-restricted locations., QC 20211025

Oil palm is one of the largest crop industries in South East Asia, thus, it is of importance to use all parts of the Oil palm trees. Recently Oil Palm Trunks (OPT) have been used to make veneer, which can be processed to produce plywood. Even though OPT plywood doesn't have the same mechanical properties as timber, with proper treatment and adhesives during the processing of veneer to plywood, it can be made to compete with hardwood. OPT plywood has been used in various applications from wooden appliances to housing and roofing structures. These structures are at risk of surface flashovers through lightning and electrical breakdowns. However, no study has been conducted on the effects or characteristics of OPT plywood. In this paper, the effects of impulse surface flashover under different conditions on three-layered OPT plywood has been analyzed. Experiments were conducted to identify the characteristics of OPT under clean and dry, clean and wet, and contaminated surface conditions for both parallel and perpendicular fiber orientations. The 50% breakdown voltage was determined by the up and down method. Results identified the importance of the fibre orientation and the decrease in breakdown voltage under contaminants., QC 20190403

Low-level currents measured prior to return strokes can potentially provide information about the properties of upward leaders during lightning flashes. However, these currents need to be properly analysed and interpreted in order to be useful for evaluating upward connecting leaders. In this paper, low-level currents measured before return strokes in two lightning events to two structures in Brazil are analysed and interpreted as case studies. The discharge current estimated from one of these events is used as input to a detailed thermohydrodynamic model with an extensive kinetic scheme for N2/O2 mixtures. The model allows the evaluation of the physical and chemical properties of upward connecting leaders. Estimates of the temperature, mass density, electric field and radius of the channel are presented for an upward connecting leader propagating in a lightning event. In addition, estimates of the axial density of electrons, ions and neutral particles (including NO and NO2) are also reported., QC 20211025

We present in this paper lightning current measurements and LMA (Lightning Mapping Array) data associated with upward flashes observed at the Sàntis Tower during Summer 2017. The LMA network consists of six stations located in the vicinity of the tower at distances ranging from 100 m to 11 km from it. 20 flashes simultaneously recorded by the current measurement system and the LMA are analyzed. Based on the lightning activity derived from the European Lightning Detection Network (EUCLID) in an area within 30 km from the tower and in a 5-second time window before the start of the flash, all the 20 flashes were classified as 'self-triggered' (ST). However, the investigations based on the LMA data reveal that 3 of the flashes were preceded by nearby activity and should be therefore classified as 'other-triggered' (OT) flashes. The results suggest that the number of OT flashes inferred from LLS data can be underestimated. © 2018 IEEE., Peer Reviewed, Postprint (published version)

Lightning striking tall towers is mainly of the upward lightning type, which is characterized by the absence of a first return stroke and the presence of an initial continuous current (ICC) with or without superimposed pulses. The Säntis Tower is 124 m tall and it is located on the top of the Säntis Mountain (2502 m ASL) in the eastern Swiss Alps. The Tower location exhibited the highest lightning flash density in Switzerland during the period from 1999 to 2006. The Tower was instrumented in May 2010 for the measurement of lightning current parameters. In order to complement these data, a Lightning Mapping Array (LMA) was deployed around the Tower during the Summer 2017. The LMA system locates the sources of radio emissions in the very high frequency range (VHF, 60-66 MHz) in three dimensions by a time-of-arrival analysis. The LMA system allows detailed analysis of individual flashes, through the mapping of the lightning channels in the cloud with sufficient time resolution and spatial precision to locate the origin and propagation of each flash. With the help of the LMA, we intend to further investigate the initiation and propagation characteristics of upward lightning emerging from the Tower. From June 29 to August 15, 2017, 33 upward flashes initiated from the Säntis tower were registered by the LMA network. These records are the first set of VHF total lightning mapping obtained in Switzerland. Preliminary results of the campaign are presented in this paper. © 2018 IEEE., Peer Reviewed, Postprint (published version)

A case study of winter upward lightning is analysed. In particular, the study focuses on the meteorological aspects that favoured the triggering of upward lightning by an instrumented tower in the eastern Pyrenees. Starting from the lightning currents measured at the Eagle Nest Tower, and taking advantage of other singular meteorological instruments deployed in the region, the obtained results showed how a small winter thunderstorm can create the necessary conditions for the inception of self-initiated upward lightning from a small tower. Beyond the particularities of the present case study, the results provide new evidence on the necessity to include upward flashes in risk assessment. © 2018 IEEE., Peer Reviewed, Postprint (published version)

The first edition of the standard IEC 61400-24, Wind Generator Systems-Part 24 Lightning Protection, was issued in June 2010, and the scope was to reflect the experiences and technical understanding of lightning protection of wind turbines by manufacturers, certification organizations, research institutes and universities. It presented background statistical information on lightning damage to wind turbines, and it provided guidance on lightning protection best practices. Since then, the wind power industry has further developed towards even larger onshore and offshore wind turbines and into a mature industry. This is the background for the current draft of the 2018 revision of the IEC 61400-24, which transforms the 2010 edition into an evolution of the previous issued standard based on improved technical experience and expertise., Peer Reviewed, Postprint (published version)

Modeling the lightning attachment process is required on any method to design the air-termination elements of a lightning protection system. An attachment model that adopts the leader progression concept is used to evaluate the three-dimensional attractive zone of a lightning rod on a common 54-m tall building in Sao Paulo, Brazil. Electric field and scalar potential distributions are calculated numerically with a finite element method. The result is compared with the interception volume predicted by the electro-geometric model, as applied by the rolling sphere method. The results show that the electrogeometric theory underestimates the striking distance and the attractive radius. Moreover, in the presence of upward connecting leaders, the striking distance varies according to the field enhancement on the geometry of the structure and the lateral displacement of the stepped leader. The simulated propagated distances and speeds of the downward and upward leaders are compared with a recently published high-speed video analysis of a natural lightning attachment case observed on the evaluated lightning rod. A reasonable agreement between the simulated and measured leader characteristics has been found.

Wind turbines are prone to damages due to lightning strikes and the blades are one of the most vulnerable components. Even though the blade tip is usually protected in standard designs, lightning damages several meters away from it have also been observed in some field studies. However, these damages inboard from the tip cannot be explained by the attachment of downward stepped leaders or the initiation of upward lightning alone. In this paper, the attachment of dart leaders in an upward lightning flash is investigated as a mechanism of strikes to inboard sections of the blade and the nacelle of large wind turbines. Dart leaders in an upward lightning flash use the channel previously ionized by the preceding stroke or the continuous current. The analysis is performed with the self-consistent leader inception and propagation model (SLIM). A commercial large wind turbine with 45 m long blades and hub height of 80 m is analysed as a case study. The impact of the prospective return stroke peak current, the rotation angle of the blade and the wind on the location of lightning strikes on this mechanism is analysed. The probability of lightning attachment of dart leaders along the blade for the case study is also calculated. It is shown that this damage mechanism could create a new strike point only when the blade of a wind turbine rotates sufficiently from its initial position (at the inception of the initial upward leader) until the start of the dart leader approach. Thus, dart leader attachment is a mechanism that can explain lightning strikes to the nacelle and to the inboard region several meters away from the blade tip in large wind turbines. However, dart leader attachment cannot explain the lightning strikes observed in the close vicinity of the blade tip (in the region between 1.5 and 6 m from it)., QC 20180115

Down conductor is one of the pivotal parts of the Lightning Protection System. It plays a key role in rerouting lightning captured by the air termination system to the earth termination system. In Malaysia, the standard practice for lightning protection is adapted from the International Electrotechnical Commission, which consists of the IEC 62305 series. For the enhancement and safe protection from lightning, external and internal lightning protection is compulsory for each protected structure (building). A straight down conductor, is ideally suited for the best-case scenario regarding reliability and safety protection. One to aesthetical aspects, down conductor is undesirably bent in most current buildings. However, only the primary bare type of a down conductor is undergone such process, and bent at a certain degree which depending on the structure itself. Neither the Malaysian Standard, IEC, nor Institute of Electrical and Electronics Engineers has ever specified the permitted bending degree of the down conductor. Therefore, the purpose of this research is to evaluate the bending degree effect on down conductors, by looking at electric field distribution around the bent area with the presence of concrete wall and reinforcement bar. The numerical analysis performed in this study referenced the implied (not formalised) manufacturing down conductor specifications which use entirely copper materials for the down conductor. The use of aluminum and galvanised iron types are also evaluated in this study. Three conditions of angles of the down conductor; smaller than 90º angles, 90º and wider than 90º angles are modelled with a minimum cross-sectional area according to the standard for the worst-case scenario with the implementation of the lightning protection system. Experimental work is further conducted to validate the results from conducting the numerical analysis. This is to ensure accuracy and completeness of the results. A thorough evaluation of the electric field

Down conductor is one of the pivotal parts of the Lightning Protection System. It plays a key role in rerouting lightning captured by the air termination system to the earth termination system. In Malaysia, the standard practice for lightning protection is adapted from the International Electrotechnical Commission, which consists of the IEC 62305 series. For the enhancement and safe protection from lightning, external and internal lightning protection is compulsory for each protected structure (building). A straight down conductor, is ideally suited for the best-case scenario regarding reliability and safety protection. One to aesthetical aspects, down conductor is undesirably bent in most current buildings. However, only the primary bare type of a down conductor is undergone such process, and bent at a certain degree which depending on the structure itself. Neither the Malaysian Standard, IEC, nor Institute of Electrical and Electronics Engineers has ever specified the permitted bending degree of the down conductor. Therefore, the purpose of this research is to evaluate the bending degree effect on down conductors, by looking at electric field distribution around the bent area with the presence of concrete wall and reinforcement bar. The numerical analysis performed in this study referenced the implied (not formalised) manufacturing down conductor specifications which use entirely copper materials for the down conductor. The use of aluminum and galvanised iron types are also evaluated in this study. Three conditions of angles of the down conductor; smaller than 90º angles, 90º and wider than 90º angles are modelled with a minimum cross-sectional area according to the standard for the worst-case scenario with the implementation of the lightning protection system. Experimental work is further conducted to validate the results from conducting the numerical analysis. This is to ensure accuracy and completeness of the results. A thorough evaluation of the electric field

In this paper, the Self-Consisting Leader Inception and Propagation Model -SLIM- is used to analyze the shielding performance of transmission lines, with special attention on the terrain topography effect. Transverse and Longitudinal terrain profiles are considered. It is found that a transmission line can be more vulnerable to be struck by lightning on any terrain that leads to increase the height of the conductors. In addition, the striking distance to the phase conductors strongly depends on the landform and the tower geometry, which suggests changes in the current lightning protection standards., QC 20170302

Based on the well-known rolling sphere method, international standards recommend the location of the external lightning protection system of structures. The design of the external lightning protection system of structures of height of less than 60 m can be done by installing a mesh on top of a roof of the structure or by creating a mesh with wires at certain distance from the roof of the structure. The prospective downward leader current that the mesh can incept depends on the size of the mesh and the current magnitude is given as recommendation in the international standards. This paper analyses the relation prospective negative downward leader current vs. mesh size from a lightning attachment model. The model is applied to a perfectly grounded structure with maximum height of 50 m protected by two different external lightning protection systems recommended by the international standards. The results showed difference on magnitude of the prospective downward leader current the standards recommend and the ones obtained using the lightning attachment model for meshes of shorter size. Discrepancies concerning the minimum downward leader current that can be incepted by a mesh made by wires located at certain distance from the ground structure and a mesh located on top of the building are obtained.

CFRP is becoming in an important material for the future blades due to alternative renewable energy industry plans to increase the length of the blades. This work shows some analytical results about potential distribution on a CFRP coupon obtained after applying an impulse current with different rise time. Effects around electrodes are, symmetry behavior and some interesting comments about the influence of the rise time appear. A FDTD simulation is done and a comparison between FDTD and analytical results. The aim is to evaluate how useful can be this technique when current distribution is over an anisotropic material since tests are not always possible., Preprint

Negative downward leaders that produced lightning strokes to wind turbines are identified by means of the Lightning Mapping Array data of the Ebro Valley Laboratory (NE Spain). Four cases are analyzed together with weather radar imagery. All flashes hitting wind turbines were originated in small convective cells with moderate development. Notwithstanding the moderate convection, all cases occurred under what can be called “out of season conditions”, where the ‘‘charging zone’’ is located closer to the ground and may favour downward leaders to tall structures. Cloud charge structures showed negative region from 3 km to more than 5 km with a low positive charge below (not always detectable)., Preprint

The paper presents winter lightning maps on specific regions in the northern hemisphere. Four different degrees of winter lightning activity are defined based on information derived from Japanese case. Based on this reference case it is possible to determine regions where winter lightning can be a threat to specific structures. Guidance on risk assessment to tall structures and wind turbines are described as well., Preprint

Multi-megawatt wind turbines are a special type of tall structures. Two characteristics stand out from other tall objects such as buildings and telecommunication towers. The first particularity is that a large part of the structure is rotating, and the second, is the extensive use of composite materials in the rotor blades. Due to these two factors, the protection against lightning requests very special attention. Wind turbines installed all over the world have shown how a particular design of their lightning protection system (LPS) can perform very different in areas with different thunderstorm climatology. Up to now, the most severe damages are reported in those areas affected by winter thunderstorms such as Japan and Europe (e.g. Honjo, 2015). These type of storms pose the most favorable conditions for upward lightning initiation from tall structures. That is because the heights of charge regions of winter thunderstorms are significantly low (e.g. Montanyà et al., 2007). On the other hand, most wind turbine blades are built wind composite materials such as glass fibers (GF) and carbon reinforced plastics (CFRP). Blades are typically composed of two shells enclosing a spar. The lighting protection system consists of one or several air terminals connected to a down conductor that brings lightning currents to ground (e.g. IEC 61400-24, 2010). However, the insulation provided by the shells is not perfect and it is possible to experience lightning attachments to non-desired locations. Some blades are equipped with electrically conductive carbon fiber reinforced plastics (CFRP), these components shall be bonded to the lightning protection system (IEC 61400-24, 2010). CFRP laminates are poor conductive presenting high anisotropy. Moreover, electrical connections to CFRP can be very complex because in most of the cases it is not possible to use bolted connections. In the first part of this work lightning interactions to wind turbines are described according to the types, Postprint (published version)

Earth’s atmospheric potential rapidly increases up to few tens of kilovolts below 200 m altitude. This potential drop will induce charge to tall objects at ground by virtue of electrostatic induction. In this work we investigate the induced electric charges in fair weather to a 1.5 MW and 5 MW wind turbines. The effect of rotation is included and the current calculated result in currents of few micro-amps. The production of point discharge and corona is investigated and some experiments are conducted by means of instrumented kites., Preprint

The size and duration of lightning flashes are examined. Data from the Ebro Valley Laboratory Lightning Mapping Array is used as reference. Additional data from the VLF/LF LINET network is included. In the analysis, each flash is simplified by a confidence ellipse fitting most of the detected sources. The major axis of the ellipse is adopted as the flash length. Flash durations are computed too. The analysis of 778 flashes results in a median flash length of ¿14 km with a median duration of ¿0.3 s. The results presented, besides characterizing the storm activity, they can be useful to define stroke grouping criteria, lightning flash density calculations and lightning warning purposes., Postprint (published version)

The major role of protection against lightning are to secure structures and every component connected to it from lightning damage by directing the high currents and dispersed it to the ground safely. Lightning protection of structures and premises becomes crucial in order to provide the safety and to ascertain that the installation of Lightning Protection System (LPS) is reliable and comply with the standards and specification assigned by the authority to assure the quality of services. LPS have been designed deliberately to get the overall protection via an external grid arrangement depends on the building constructions and level of protection needed as per standard. A LPS is composed of three main parameters which are the air termination network, the down conductor and the earth termination. The down conductor is the medium to divert the lightning current from the air termination to the earth termination system of protected structures. This research focused on the down conductor and its effects when it meets the bending part in the LPS installation. According to the standards and specifications, the down conductor shall be installed as short and straight as possible with particular attention shall be carried out eliminating sharp bends and curves to provide a low impedance path between the air termination network to the earth termination. However, due to the modern architecture and to fulfill aesthetical requirement of the building, the bending seems unavoidable. The aim of the research is to investigate and analyze the effect of the bending degree of the down conductor in the LPS installation since no particular experiment has been channeled away to this topic so far. Numerical (simulation) analysis has been applied using Ansoft Maxwell software. The down conductor in concern for the simulation is an Annealed Copper Tape that was injected with lightning impulse current waveforms as per standard at the various bending degree.The potentials and the fields involved

The major role of protection against lightning are to secure structures and every component connected to it from lightning damage by directing the high currents and dispersed it to the ground safely. Lightning protection of structures and premises becomes crucial in order to provide the safety and to ascertain that the installation of Lightning Protection System (LPS) is reliable and comply with the standards and specification assigned by the authority to assure the quality of services. LPS have been designed deliberately to get the overall protection via an external grid arrangement depends on the building constructions and level of protection needed as per standard. A LPS is composed of three main parameters which are the air termination network, the down conductor and the earth termination. The down conductor is the medium to divert the lightning current from the air termination to the earth termination system of protected structures. This research focused on the down conductor and its effects when it meets the bending part in the LPS installation. According to the standards and specifications, the down conductor shall be installed as short and straight as possible with particular attention shall be carried out eliminating sharp bends and curves to provide a low impedance path between the air termination network to the earth termination. However, due to the modern architecture and to fulfill aesthetical requirement of the building, the bending seems unavoidable. The aim of the research is to investigate and analyze the effect of the bending degree of the down conductor in the LPS installation since no particular experiment has been channeled away to this topic so far. Numerical (simulation) analysis has been applied using Ansoft Maxwell software. The down conductor in concern for the simulation is an Annealed Copper Tape that was injected with lightning impulse current waveforms as per standard at the various bending degree.The potentials and the fields involved

The effect of structure height on the lightning striking distance is estimated using a lightning strike model that takes into account the effect of connecting leaders. According to the results, the lightning striking distance may differ significantly from the values assumed in the IEC standard for structure heights beyond 30m. However, for structure heights smaller than about 30m, the results show that the values assumed by IEC do not differ significantly from the predictions based on a lightning attachment model taking into account the effect of connecting leaders. However, since IEC assumes a smaller striking distance than the ones predicted by the adopted model one can conclude that the safety is not compromised in adhering to the IEC standard. Results obtained from the model are also compared with Collection Volume Method (CVM) and other commonly used lightning attachment models available in the literature. The results show that in the case of CVM the calculated attractive distances are much larger than the ones obtained using the physically based lightning attachment models. This indicates the possibility of compromising the lightning protection procedures when using CVM.

Meteorological parameters associated with the initiation of upward lightning discharges from a tall tower were investigated. The parameters, including temperature, wind speed, air pressure, and relative humidity, were measured at the Gaisberg Tower top and at a distance of 170 m from the tower. A comparison of parameters associated with self-initiated upward flashes (initiated without any nearby preceding lightning activity) and nearby-lightning-triggered upward flashes (triggered by nearby preceding lightning activity) was made. It shows that at the Gaisberg Tower (GBT), relatively low ambient temperature facilitates to initiate upward flashes without any nearby preceding lightning activity. Relatively high ambient temperature (8.5 °C to 15.5 °C) facilitates to initiate upward positive stepped leaders, rather than the common continuous leaders, in the self-initiated upward negative flashes. No reliable correlation between wind speed and upward initiation of lightning was found., QC 20150608

The heavy haul rail network in Queensland Australia generally adopts a lightning impulse withstand voltage rating of 250 kV for the switchgear and autotransformers within its 50 kV ac traction feeder stations. The aging switchgear across a number of feeder stations in this network are undergoing upgrade and the rail network operator is considering the possibility of using 200 kV rating for the upgraded switchgear. This paper investigates the lightning over-voltages that could occur at the feeder stations under review. Fast front transient models of the feeder stations and the associated traction corridors are developed in PSCAD/EMTDC software. Simulations are conducted to evaluate the likely over-voltages under various scenarios and the results are presented. Finally, the required lightning impulse withstand voltage rating for the switchgear is determined based on the simulation results.

Transients from lightning strikes can enter underground cables at overhead line to power cable transitions. Possible overvoltages on these surges at cross-bonding connections of the cable screens are of major concern. A model is developed for modelling overvoltages from transient signal propagation through a combined cross-bonding cable and box. This model is applied to the first Dutch 400 kV cable connection. Such model incorporates model parameters whose values depend on design details of the cross-bonding box. The values for these model parameters are extracted from the measured transmission and reflection signal on steep pulses injected into the actual cross-bonding box configuration. The model combines transmission line description for the cross-bonding cables with mainly inductive behaviour of the cross-bonding box. The obtained results are verified by measurements. The model is applied to investigate overvoltages induced at the cross-bonding cable and box on 1.2/50 ?s impulse voltage injection representing a lightning impulse voltage applied to the core conductor of the cross-bonding cable. Furthermore, the effectiveness of surge arresters to reduce overvoltages at the cross-bonding cable screen is demonstrated by simulations with this model in PSCAD., Electrical Sustainable Energy, Electrical Engineering, Mathematics and Computer Science

Wind turbines emit lightning flashes upwards, producing these electrical discharges at regular intervals relative to the turbine’s rotation, and can do so tens of kilometres away from an active thunderstorm area., Peer Reviewed, Postprint (published version)