Monte Carlo Simulation-Based Method for Evaluating Sample Thickness Variation to Improve Reliability of Dielectric Strength Assessment

This study investigated the thickness effect (the influence of sample thickness variation) on the assessment of the dielectric breakdown strength in XLPE and PP insulators. A Monte Carlo simulation (MCS) was conducted to quantify the impact of voltage and thickness on the dielectric strength. Aimed at improving power system reliability, the study sought to provide a quantitative basis for the thickness effect and propose a reasonable range of thickness variation, specifically between 0.2 mm and 1.1 mm. The simulation was repeated 1,000 times by modeling thickness deviations ranging from 1% to 10%. Levene’s test was used to assess the homogeneity of variance between an ideal group with a 1% thickness deviation and comparison groups with larger deviations. The proportion of cases where Levene’s test produced a p-value below the significance level reduced below 80% when the thickness variation exceeded 2.5%. This verified that the variance differences were statistically significant. This result (particularly for samples with thicknesses of at most 1 mm) provides a scientific basis for establishing tolerance standards for thickness variation. Thereby, it contributes to enhancing the reliability of dielectric strength testing methods.