Seismic fragility analysis of a 220 kV zinc oxide arrester
Arresters in substations are prone to damage during earthquakes,so it is necessary to conduct the seismic assessment.To investigate the seismic performance and vulnerability of a 220 kV surge arrester,a refined finite element model of the 220 kV zinc oxide surge arrester-bracket system was established.Through numerical simulations,seismic response analysis was conducted initially to study the seismic response characteristics and seismic resistance capability of the surge arrester.Subsequently,vulnerability analysis of the surge arrester was performed under multiple uncertainties,such as seismic motion,structural aspects of electrical equipment,and cognition.Finally,a probabilistic seismic demand model was established to fit the relationship curve between the failure probability and peak ground acceleration of the surge arrester.The results indicate that under the influence of a seismic action with a fortification intensity of 9 degrees,the 220 kV zinc oxide surge arrester exhibits strong seismic resistance,and the failure probability is only 0.03.The amplification factors for the bracket are 1.915,exceeding the minimum specified value of 1.2 in current standards.This suggests that the actual amplifying effect of the bracket should be considered in practical studies.Additionally,in seismic vulnerability analysis,the median seismic resistance capability of the surge arrester is 0.79 g.With the increase of the considered uncertain factors,when the seismic intensity encountered is below the median seismic resistance capability of the equipment,the probability of electrical equipment failure increases.Conversely,when the encountered seismic intensity is higher than the median seismic resistance capability of the equipment,the failure probability decreases.Therefore,the influence of multiple uncertainties should be considered when analyzing the seismic vulnerability of electrical equipment.The study in this article provides valuable reference and guidance for the seismic design of surge arresters and the assessment of failure probabilities under different seismic intensities.
arresterfinite element analysisseismic fragilityprobabilistic seismic demand modelmultiple uncertainties
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