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Multiple strokes are the main factors affecting the safe and stable operation of power equipment. As the core lightning protection equipment, arresters are also frequently thermally collapsed due to multiple strokes. This paper investigates thermal effects of polymer-housed metal-oxide surge arrester (PMOSA) under multiple strokes. The comparative experiments of PMOSA lightning impulse are carried out through multiple strokes of experiment platform, including continuous lightning stroke and multiple strokes. Furthermore, the temperature distribution of the housing surface is obtained by infrared imager for thermal effect analysis. Subsequently, some typical DC parameters are tested to explore the association of impulse aging and thermal effects of the arrester under multiple strokes. Finally, a thermal-electric coupling model (TECM) is constructed to investigate the influence of some factors on the temperature of PMOSA from the perspective of materials and structure. The research in this paper can provide a theory reference and brief data support for improving the heat dissipation performance of arresters under multiple strokes based on structural optimization design and material modification. [ABSTRACT FROM AUTHOR]

This paper evaluates the lightning-induced voltages of two typical multiconductor lines configurations with or without shielding wires over lossy ground for striking the cone-shaped mountain top, by means of a cylindrical two-dimensional finite-difference time-domain method and Agrawal coupling model. It is found that the lightning-induced voltages both for the vertical and the horizontal configurations can be enhanced obviously for striking to the cone-shaped mountain, compared with the case of flat terrain, especially for the lower finite ground conductivity. The larger mountain inclining angle results in the higher peak values of lightning-induced voltages, which can be explained by the enhancement of lightning electromagnetic fields due to wave reflection of the transition between mountain terrain and flat ground. Moreover, the shielding wires can effectively reduce the voltages induced at both ends of the phase lines. [ABSTRACT FROM AUTHOR]