Navegando por Assunto "Densidade de raios"

Agora exibindo 1 - 2 de 2

Acesso aberto (Open Access)
Análise de sensores de descargas atmosféricas: protótipo de um detector de raios com estimativa de densidade de raios para região amazônica utilizando PSoC
(Universidade Federal do Pará, 2014-02-24) LEAL, Adônis Ferreira Raiol; ROCHA, Brigida Ramati Pereira da; http://lattes.cnpq.br/9943372249006341
This work proposes the design of a prototype for detect lightning, which will, count the number of lightning detected, calculate the density of lightning to the area of operation of the sensor and to estimate the peak of the variation of the electric field for the instant occurrence of discharge. A study of atmospheric electricity, types of lightning, emission of electromagnetic waves during the occurrence of the lightning , types of electromagnetic sensors and lightning detection networks gave subsidy to the design of the prototype . The prototype consists of two antennas, one loop antenna and a flat plate antenna , and electronic circuits , these electronic circuits are implemented mostly in PSoC device ( Programmable System -on - Chip ) , which is a relatively new technology that works with analog and digital signals and also has a CPU to perform the processing of these signals . The validation of the data obtained and estimated coverage area of the sensor, were based on data from STARNET network (sferics Timing And Ranging NETwork). The prototype was designed to be low cost, have a simple and straightforward interface and can be installed in the Amazon region.
Acesso aberto (Open Access)
Processo de attachment, densidade de raios e a ocorrência de flashover em linhas de transmissão de eletricidade
(Universidade Federal do Pará, 2014-12-19) PEREIRA, Carlos Simões; ROCHA, Brigida Ramati Pereira da; http://lattes.cnpq.br/9943372249006341
This thesis refers to the use of leaders attachment model (Leader Progression Model - LPM) in the estimation of striking distance values and jointly use of lightning density data gathered by a LLS System to estimate the flashover rate of electricity transmission lines in the Amazon region. The leader progression model developed here is called ModSalto, and to estimate the striking distance, it: integrate the linear density of the leader electric charge proportional to the prospective lightning first stroke (Ip) to estimate the electric field produced by the descending leader, in the tip of the structure under study (arrester, electric conductor, etc.); makes integration of the image leader charge distribution and makes use of the power of tips as a stimulus and intensification factor for the electric field due to the streamers on the edge of the structure under study, to time the attachment process. The trigger of the descending leader is hypothesized to be on behalf of packets of charges turbulent domains in cloud, and the leader's behavior on the descending path is hypothesized to obey the equation of the Lorentz force in the space of movement of electric charges of the leader, influenced by crossed electric field due to the electrification of the clouds and the Earth's magnetic field, which imprints a cycloid motion on the leader’ tip electric charges which may explain the stepped and tortuous nature of the downward leader. The LFR parameters (Lightning Flashover Rate) is presented as an estimate of the probability of occurrence of flashover induced by lightning on an electric transmission line, that may be derived by a defined parameter Jv (Vulnerability Window) as a quantifying factor to the probability of insufficient protection provided by the EGM model to the transmission line, protected against lightning with use of shielding conductors (shield wire). With the aim to get a usable lightning density data, we do a reanalyze of the dataset of occurrence of lightning collected by LLS SIPAM, from October 2006 to July 2008 in the amazon region, with over 3 million hits, comparing them with data from instrumented towers allowing an assessment of the quality of such data. Terrain elevation data (SRTM) from NASA are used to generate attraction radius (Ra) formulas that takes into account the height of the structures and jointly with Log Normal distribution parameters describing the statistical behavior of first pulse current values (stroke) of the lightning, as estimated by LLS SIPAM, to generate a summation or integration area of attraction formula, used in the quantification of the number of lightning which are likely to hit a given structure, depending on the density of lightning (lightning / km2 / year) at the study site.