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Evaluation of lightning return stroke parameters using measured magnetic flux density and pso algorithm

Izadi M., Ab Kadir M. Z., Gomes C., Askari M. T.

Przegląd Elektrotechniczny

2012

R. 88, nr 10a

201-204

Return stroke current along lightning channel is reckoned as a fundamental factor for the prediction of electromagnetic fields at observation points, whilst it can be simulated by current models. The most common current model is the engineering model which is more dependent on the height dependent attenuation factor and the return stroke velocity. Yet, the estimation of constant parameters at attenuation factor and return stroke velocity value are complicated. Using measured values and the PSO (particle swarm optimization) optimization method, this paper aimed at determining the values of current velocity along lightning channel and constant parameters in MTLE and MTLL engineering current models and the behaviour of both current models with respect to measured field were processed where the observation point is set at intermediated distance from lightning channel. Moreover, the results were compared with the previous results and were validated with the measured fields. The results illustrated that the MTLL model cannot be as an appropriate current model compared to MTLE current model for the intermediate distance case. Also, the results based on the MTLE model and the initial data determined by PSO algorithm were in good agreement with the measured fields. The proposed method was also capable of setting up appropriate values for unknown parameters in return stroke current models. In addition, the simulated field using the MTLE current model and initial data from PSO algorithm improved the average difference in percent between simulated field and measured field compared to the initial data from previous studies.

W artykule analizuje się prędkość prądu w kanale wyładowania piorunowego. Do tego celu wykorzystuje się dane pomiarowe i algorytm PSO. Metodę tę porównano z klasyczną metodą bazującą na określaniu tłumienia i szybkości uderzenia powrotnego. (Analiza prądu w kanale wyładowania piorunowego na podstawie pomiaru indukcji magnetycznej z wykorzystaniem algorytmu PSO)

Analytical Field Expressions due to Inclined Lightning Channel

Izadi M., Ab Kadir M. Z., Gomes Ch., Wan Ahmad W. F.

Przegląd Elektrotechniczny

2011

R. 87, nr 11

277-280

In order to have a fast determination of electromagnetic fields peaks associated with inclined lightning channel, the analytical electromagnetic field expressions were proposed, assuming a pulse shaped return stroke current at channel base and by considering the channel angle and the observation point angle effects on the electromagnetic fields. Also, the return stroke velocity effects on the peaks of electromagnetic fields were processed. The results were compared with the perpendicular lightning channel case. The proposed fields' expressions are very useful in determining the peak values of electromagnetic fields, since they are considered as critical parameters in estimation of lightning induced voltage peak on the power line.

Zaproponowano analityczną metodę wyznaczania pola elektromagnetycznego towarzyszącego odchylonemu kanałowi wyładowania. Przyjęto impulsowy kształt uderzeniowego prądu. Przeprowadzono obliczenia dla różnych kątów kanału wyładowania.