Wang Jufeng

Use of Magnetic Links to Measure the Maximum Rate-of-Rise of Lightning Currents

The maximum rate-of-rise of lightning currents is a critical parameter in lightning protection. The study shows that with two magnetic links, which are prerecorded with calibrated signal, laid simultaneously nearby the lightning channel and in quadrature with each other, the maximum rate-of-rise of lightning currents can be measured directly. The physical and mathematical models are established to describe the demagnetization of the links. The signal-erased length for the link placed in parallel way is determined by the lightning field intensity as well as the inducted current in the link which is proportional to the maximum rate-of-rise; and the signal-erased length for perpendicularly placed link solely relates to the lightning field intensity, the inducted current effect is negligible in this case. So, by calculating the difference between two signal-erased lengths, the maximum lightning rate-of-rise can be determined. The experiments show that the measuring error of this method is less than 5%.

Vector Electric Geometry Model

The classical electric geometry model unifies the thunder and lightning flashover characteristic logical circuits structure size, very good explained the line shield expiration phenomenon. But the classical electric geometry model had not considered that the lightning leader the electrical field intensity influence, is being circled strikes the segmental arc is the zero hour, the line still had circles strikes the occurrence. Proposed originally the vector electric geometry model, considered fully the thunder stroke leader receives the electric field action of force, will have a better precision, in the article to the vector electric geometry model key elaboration.