Statistics on tropical lightning and its interaction with power systems

Abstract

The CIGRE lightning flash counter is a standardized device, which, by registering the number of lightning flashes within a specified area, enables the density of lightning flashes to ground, per unit area and per unit time, to be estimated. Long-term average values for the number of lightning flashes per year were obtained for Papua New Guinea from a lightning flash counter network. These records are used with local storm observations to obtain the ground flash density N g . The average number of thunder-days (T) and lightning-days (L) are estimated. The values are compared with data from the literature of other regions used in transmission system design. Although route lengths and the number of system voltages in Papua New Guinea are limited, interesting indications of performance are obtained from an analysis of fault records in conjunction with flash counter data. In many cases performances were found to be less than would be acceptable elsewhere. Average values as high as about 20 lightning faults per 100 km per year were measured. It is apparent that designs from temperature countries would require adaptation for the higher incidence of lightning in this country, although the lower values of N g will compensate to some extent for the higher values of number of lightning flashes.