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Keywords

continuous lightning strike, conductive concrete, thermal effect, ATP‑EMTP

Abstract

Conductive concrete applied as power transmission tower foundation grounding has been piloted in many domestic engineering projects. However, the temperature rise characteristics of conductive concrete foundation under continuous lightning impact still need further theoretical analysis and experimental research. In this paper, the spark effect of soil ionization under continuous lightning impact and its cumulative effect are considered. An ATP-EMTP simulation model for the dispersion effect of conductive concrete tower foundation is established. The thermal stability of the conductive concrete foundation suffering continuous lightning strike is calculated, which provides theoretical reference for engineering practice. The results show that the thermal effect of conductive concrete foundation changes the salinity and water content of the surrounding soil under lightning impulse. Thus, the resistivity of the surrounding soil is improved, which results in 6.56% increase of the grounding resistance. When the number of continuous lightning impulse n≤2, the temperature rise of conductive concrete foundation Δt=287.06<300 ℃, the conductive concrete foundation of tower is safe and stable. Once n≥3, the temperature rise Δt>300 ℃, the structure of conductive concrete foundation may be destructed, which may bring safety risks to the stable operation of power system. Therefore, in actual engineering applying conductive concrete foundation grounding, the resistivity of the soil around the foundation should be reduced to improve the dissipative heat capacity.

DOI

10.19781/j.issn.1673-9140.2024.02.028

First Page

249

Last Page

254

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