Lightning Parameters of a Tropical Region for Engineering Application: Statistics of 51 Flashes Measured at Morro do Cachimbo and Expressions for Peak Current Distributions

The statistics of lightning currents parameters of 51 negative cloud-to-ground flashes measured at Morro do Cachimbo Station was developed. The data comprising 51 currents of first return strokes and 77 currents of subsequent return strokes measured since 1985 composed the only database obtained in tropical regions with statistical significance. The previous result of median and maximum peak currents of about 40%–50% higher than the counterparts measured at Mount San Salvatore, obtained for 31 flashes, was confirmed. Median peaks of 43.3 and 17.3 kA and maximum peaks of 153 and 65 kA were found for first and subsequent return strokes, respectively. Expressions correlating the peak current and front time were developed for first return strokes. Formulae expressing the probability of peak-current occurrence of first and subsequent return strokes were derived from the respective cumulative distributions for direct application in the assessment of the lightning performance of electrical systems.