资源环境科技发展态势分析平台

Return-stroke current and electric field play important roles in atmospheric electricity research. Aim of this paper is to examine the empirical formulas for calculating return-stroke peak-current in lightning location system according to sensored peak-electric-field, and to evaluate the detection efficiencies and the peak-current estimation of the Foshan Total Lightning Location System (FTLLS). Lightning was initiated artificially by rocket triggering procedure and the current waveform was recorded at the lightning channel-base. A total of 43 return-strokes in 8 flashes were triggered succesfully in 2014. Nine different regression formulas providing the best fit to the measured current-and-field data were derived. The empirical formulas were based on the directly measured return-stroke current and electric fields of 38 return-strokes within 4 flashes. The empirical formulas analyzed in the present study demonstrate the regional difference of the empirical formulas for various geographical-distributed stations of the FTLLS in Foshan, China. On the other hand, the return-stroke speeds were theoretically derived though the transmission line model considering the already known parameters of the corresponding measured-peak-current at triggering lightning site. The nine empirical formulas from the nine stations of the FTLLS were analyzed by the fact that the values of the inferred return-stroke speeds for each return-stroke and for each station are reasonable compared to those in the previous literatures. In addition, the detection efficiencies and peak-current estimation of the FTLLS and the LLS of Guangdong power grid in Guangdong Province were examined and were compared based on the directly measured current data at the triggering lightning site. It is shown that the detection efficiencies of the FTLLS for flashes and for return-strokes were 87.5% (7/8) and 93.0% (40/43), respectively. The peak-current estimation error reported by the FTLLS was 8% on average. The absolute value of the maximum error for the individual return-strokes were around 28%. Performance comparison to other global/regional lightning location systems are also presented.