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A recognition method of the thunder signal based on the end-point detection method with a noise-estimation algorithm for highly non-stationary environments is proposed. To determine the parameter of the algorithm and verify the effectiveness and accuracy of the method we analyze the acoustic signals obtained from two microphone arrays installed at the top platform on a seven-floor building in Wuhan. In this paper, we have chosen two acoustic signals to test the endpoint detection method. It is revealed from the recognition result that the method can find out the accurate beginning and ending time of the thunder signal from the acoustic signals.

A single-station-based three-dimensional (3D) acoustic lighting mapping system comprising a microphone array has been developed and used for lightning observations, in which a new broadband direction-of-arrival (DOA) estimation techniques namely incoherent signal-subspace method are proposed for thunder signals in the far-field. Two cloud-to-ground (CG) flashes with highly branch channels recorded by the system are analyzed and presented in this paper. The acoustic mapping results can not only locate on the main channel produced by the return stroke process but also depict the branch channels. Moreover, the located thunder sources by the mapping system and the photography of the high speed camera agree well with each other demonstrating the effectiveness and correctness of the estimation techniques and the mapping system.

In order to obtain optical path photographs of lightning strike with a higher resolution, providing the necessary technical means for the accurate identification of 500kV transmission line lightning fault in mountain area, we developed an embedded, low-power remote online Lightning Optical Path Monitoring System based on 3G communication technology. Then, a case containing a lightning which struck the transmission line was analyzed in this paper combined with the results of the Lightning Optical Path Monitoring System, State Grid Lightning Location System and the Transmission Line Distributed Fault Diagnosis System.

Almost all modern buildings use steel mesh, when a large current occurs nearby, such as a lightning return stroke happens, for the law of electromagnetic induction, electromagnetic fields generated by the lightning would certainly be affected. In general case, lightning detection stations are generally placed near the buildings, so the received signal would be affected by the buildings nearby. In this paper, we use FEKO to make geometric models of buildings, with MOM method to calculate whether or how the buildings impact the lightning magnetic field radiation.

Lightning warning is an essential means and a key technology for lightning disaster reduction. Passivity is the main drawback of existing lightning warning methods. This paper present a lightning prediction technology based on spatial clustering method to predict lightning motion by utilizing realtime and historical lightning monitoring data of lightning location system. On the contrary to the existing passive lightning prediction and warning methods, this technology initiatively predicts the prospective lighting area. The independent, discrete, random-happen flashes are aggregated to different thunderstorm groups similar to thunderclouds by the spatial clustering method presented in this paper. The position prediction of lightning can be achieved by tracking these thunderstorm groups and calculating the movement direction and speed of them. The lightning prediction method is applied to a certain region of central China. The experiment result shows that the predicted and real positions of lightning are approximately consistent. The average prediction accuracy is around 75%. Important support will be provided for improving the accuracy and reducing the false alarm rate of lightning warning by the presented technology.

There are complicated climate and geographical environment in the Three Georges Area. Besides, there are frequently lightning activities in this area. Therefore, the lightning protection performance of transmission line is very weak. In order to improve power supply stable and reliable, it is very important to improve the evaluation and rebuilding levels of lightning protection for transmission lines. This paper researches on the lightning protection of 220kV typical transmission line based on differentiation technology and strategy of lightning protection. In detail, analyzing the differences of lightning activities, terrains and topographic features, line's structures and insulation configurations, lightning risk can be evaluated. Then, differentiation scheme of lightning protection can be proposed based on evaluation result.

In order to analyze the correlativity between the lightning flashover amount and the time factors, about 425 times lightning flashover on 187 lines in 10 power supply companies of 220 kV and 500 kV transmission lines during 2000~2007 are investigated in this paper. The correlativity between the lightning flashover amount and the time factors is analyzed. According to the lightning stroke accidents investigation records, the lightning flashover amount of transmission line increases from the year of 2000 to 2007. In each year lightning flashovers mostly happen in the month of June, July and August. Similarly in each day the flashover amount also varies with the time of day obviously. These lightning flashovers mainly occur during 14:00~21:00 in the afternoon. The analysis results in this paper have a good agreement with the meteorological observations. And these results provide good reference for the lightning protection work in power system.