Indirect electrode or direct electrode? A revisitation of electrode configuration in simulated lightning damage testing

The damaged area and depth of materials caused by lightning are key parameters in laboratory lightning testing, but these results are influenced by the experimental setup. This work studies the advantages and drawbacks of the use of a direct electrode or indirect electrode by combining experimental results and numerical modeling. Using the indirect electrode, the impacts of the arc energy and over-pressure wave are constrained by the dielectric electrode head. Net emission coefficient, electrical and thermal conductivity of arc channel are altered with added metal vapor from the ignition wire. These reasons lead to milder damaged area and depth of materials in lightning testing. Using the direct electrode overcomes the aforementioned deficiencies but faces an obstacle of self-melting. A special tungsten-copper electrode may be taken as a compromised solution. This work contributes to diminishing the misinterpretation from the testbed in laboratory lightning certification.