Lightning Induced Overvoltages Caused by Non-Vertical Lightning and Earth Current Behavior (original) (raw)
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11th International Symposium on High-Voltage Engineering (ISH 99), 1999
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IEEE Transactions on Electromagnetic Compatibility, 2012
Effects of lightning channel tortuosity and tilt on lightning electric fields and voltages induced on overhead conductors are examined. Overall inclination of the bottom few hundred meters of the lightning channel can appreciably change both the ground-level vertical electric field at distances less than 1 km or so and induced voltage peak relative to the vertical-channel assumption. Smaller-scale tortuosity is responsible for the fine structure of field and induced voltage waveforms. This fine structure can be pronounced at some hundreds of meters and beyond, but is insignificant at shorter ranges. Index Terms-Electromagnetic (EM) coupling, lightninginduced voltages, overhead lines.
Evaluation of Lightning Horizontal Electric Fields Over a Finitely Conducting Ground
Lightning electromagnetic fields radiated during the return stroke phase may induce overvoltages on overhead conductors. These transients can damage sensitive electronic equipment and provoke line flashovers, thus degrading the performance of distribution and telecommunication networks. This paper presents and discusses the characteristics of the horizontal component of the electric field produced by negative cloud-to-ground flashes during the return stroke phase. The analysis considers the influences of the distance between the return stroke location and the observation point, the soil type and the stroke current propagation velocity. The TL model is adopted for the determination of the current distribution along the return stroke channel, whereas the effect of the finite ground conductivity is taken into account by using the Cooray-Rubinstein approximation. The results show that, regardless of the ground conductivity, the distance from the lightning strike point has a great influe...
IEEE Transactions on Electromagnetic Compatibility, 2000
Currents induced in: 1) a 100 m×30 m buried rectangular loop conductor (counterpoise) and 2) a grounded vertical conductor of 7-m height by natural and rocket-triggered lightning at distances ranging from 60 to 300 m were recorded in 2005 at the International Center for Lightning Research and Testing (ICLRT). The peak values of 12 triggered lightning channel-base currents and the peak values of the induced currents in the counterpoise are strongly correlated. The first few microseconds of the current induced in the vertical conductor by triggered lightning return strokes 100 m away resemble electric field time-derivative waveforms simultaneously measured at the ICLRT. During a close natural lightning flash, five pre-first-return-stroke current pulses with peak currents up to 140 A were measured in the vertical conductor. These are apparently associated with multiple attempts of an upward-moving unconnected leader occurring in response to the charge lowered by downward-propagating leader steps.