Point Discharge Currents from a Sharp-tipped Lightning Rod Due to Lightning
Simultaneous measurements of electrical field waveforms and point discharge currents from lightning rods have been conducted for the study of responses of lightning rods to nearby lightning discharges. The point discharge currents measuring system, which consists of a sharp 34 cm high copper rod earthed via a 10 kilo-ohm resistor, has a bandwidth of DC ~ 1 MHz and a gain of 100 μA per volt. A capacitive fast antenna system with a bandwidth of 70 Hz ~ 3.6 MHz and a gain of 665 V/m per volt is used for measuring the electric field waveforms. Results show that the point discharge current measuring system has much stronger responses to processes such as preliminary breakdowns and stepped leaders than the fast antenna when compare to return strokes. The point discharge currents associated with intensive electric fields are usually consisted of a series of irregular pulses superposed on a continuous component. Whilst those associated with weak electric fields are a series of narrow bipolar pulses with a regular interval of about 18 μs and uniform amplitude of about 30 μA. These regular narrow bipolar pulses may be interpreted as the result of the threshold of electrical field to trigger corona discharges, the height and sharpness of the lightning rod, and the dispersion of corona charges around the rod tip.
Mingli CHEN Yaping DU
Department of Building Services Engineering, The Hong Kong Polytechnic UniversityHung Hom, Kowloon, Hong Kong SAR of China
国际会议
第13届国际大气电学会议(The 13th International Conference on Atmospheric Electricity)
北京
英文
2007-08-13（万方平台首次上网日期，不代表论文的发表时间）