Search results for "Lightning"
showing 10 items of 54 documents
Lightning-current distribution in MV grids interconnected earthing systems
2017
The paper presents first investigations results on the effects of lightning stroke on medium voltage (MV) installations' earthing systems, connected together with the metal shields of the MV distribution grid cables. The study enables to evaluate the distribution of the lightning current among interconnected earth electrodes in order to assess if the interconnection, usually done for reducing earth potential rise during an earth fault, can give place to dangerous situations far from the installation hit by the lightning stroke. Two case studies of direct lightning stroke are presented and discussed: two interconnected MV substations of the MV grid; a high voltage/medium voltage (HV/MV) stat…
Finite-Difference Time-Domain Simulation of Tower and Grounding Subjected to Lightning
2015
In this paper the behavior of a tower and its grounding system, subjected to a lightning, is faced. Finite difference time domain (FDTD) method has been chosen in order to study the non-linear time domain behavior of the system. The electromagnetic problem has been described by using two type of first order time derivative equations: Maxwell's equations and Telegraph equations. Aim of this work is to evaluate the possibility of a flashover between tower and power line, by considering different cases of study.
Transmission line meshes for computational simulation of electromagnetic modes in the Earth's atmosphere
2007
PurposeTwo transmission line meshes to simulate electromagnetic waves in the Earth's atmosphere are developed, one with the link transmission lines connected in parallel and the other with connections in series.Design/methodology/approachThe equations describing propagation of waves through these parallel or series meshes are equivalent to the Maxwell equations for TEr or TMr modes in a spherical cavity with lossy dielectric material between the external conducting surfaces, respectively.FindingsThe transmission line meshes are used for a numerical study of the natural electromagnetic noise due to lightning discharges in the Earth‐ionosphere cavity.Originality/valueThe numerical algorithm f…
Finite-Difference Time-Domain Simulation of Towers Cascade Under Lightning Surge Conditions
2015
In this paper, the simulation of towers cascade under lightning surge conditions is presented. Finite-difference time-domain method is used to solve both the Maxwell's and telegraph equations. Maxwell's equations and the time-domain resistivity model of Darveniza are used to simulate the nonlinear behavior of the grounding system. Telegraph equations are used to describe the propagation in the overhead lines. Multiple ionizations, on different grounding electrodes belonging to various towers, can be implemented simultaneously, without making assumptions on the shape of the ionized areas.
A new population of terrestrial gamma‐ray flashes in the RHESSI data
2015
Terrestrial gamma-ray flashes (TGFs) are the most energetic photon phenomenon occurring naturally on Earth. An outstanding question is as follows: Are these flashes just a rare exotic phenomenon or are they an intrinsic part of lightning discharges and therefore occurring more frequently than previously thought? All measurements of TGFs so far have been limited by the dynamic range and sensitivity of spaceborne instruments. In this paper we show that there is a new population of weak TGFs that has not been identified by search algorithms. We use the World Wide Lightning Location Network (WWLLN) to identify lightning that occurred in 2006 and 2012 within the 800 km field of view of Reuven Ra…
Enhanced detection of terrestrial gamma-ray flashes by AGILE
2015
Abstract At the end of March 2015 the onboard software configuration of the Astrorivelatore Gamma a Immagini Leggero (AGILE) satellite was modified in order to disable the veto signal of the anticoincidence shield for the minicalorimeter instrument. The motivation for such a change was the understanding that the dead time induced by the anticoincidence prevented the detection of a large fraction of Terrestrial Gamma‐Ray Flashes (TGFs). The configuration change was highly successful resulting in an increase of one order of magnitude in TGF detection rate. As expected, the largest fraction of the new events has short duration (<100 μs), and part of them has simultaneous association with light…
Development of a Low-Cost IoT System for Lightning Strike Detection and Location
2019
Lightning and thunder are some of the most violent natural phenomena. They generate a great deal of expenditure and economic loss, especially when they strike in cities. The identification of the concrete geographic area where they strike is of critical importance for emergency services in order to enhance their effectiveness by doing an intensive coverage of the affected area. To achieve this purpose at the city scale, this paper proposes the design, prototype, and validation of a distributed network of Internet of Things (IoT) devices. The IoT devices are empowered with lightning detection capabilities and are synchronized with the other devices in the sensor network. All of them cooperat…
Development of a low-cost IoT system to detect and locate lightning strikes
2020
Lightnings are violent natural phenomena and can generate many expenditures, specially when they strike in urban areas. The identification of the concrete geographic area where they strike is of critical importance for emergency services in order to enhance their effectiveness by doing an intensive coverage of the affected area. To achieve this aim, this paper proposes a design, prototype and validation of a distributed network of Internet of Things (IoT) devices to enable detection and location of lightning strikes. The IoT devices are empowered with lightning detection capabilities and are synchronized with the other devices in the sensor network. All of them cooperate within a network th…
Remote Sensing Observations of Thunderstorm Features in Latvia
2017
AbstractThunderstorms are the most hazardous meteorological phenomena in Latvia in the summer season, and the assessment of their characteristics is essential for the development of an effective national climate and weather prediction service. However, the complex nature of convective processes sets specific limitations to their observation, analysis and forecasting. Therefore, the aim of this study is to analyse thunderstorm features associated with severe thunderstorms observed in weather radar and satellite data in Latvia over the period 2006–2015. The obtained results confirm the applicability of the selected thunderstorm features for thunderstorm nowcasting and analysis in Latvia. The …
New circuital models of grounding systems and PDS for EMI analysis during a lightning strike
2005
In this paper circuital models of a Power Drive System (PDS) and of grounding systems are proposed in order to analyse Electromagnetic Interferences (EMI) induced in a PDS when a lightning current flows in the grounding system. The models have been developed adopting the network approach with lumped parameters and have been implemented using the software MATLAB. A High Frequency (HF) model suitable to simulate the impulse response of a PDS is described and a generalized method in order to calculate the lumped parameters values of grounding system models is presented. The new method takes into account the burial depth of electrodes as regards their length. The validation results of this new …