Sensitivity analysis of hydrostatic test for defect-elimination in ultra-high voltage and large-tonnage insulators

Porcelain insulators are essential for the mechanical and electrical reliability of overhead transmission lines, especially in Ultra High Voltage (UHV) systems. Manufacturing defects such as pores, impurities, and microcracks can threaten their integrity under stress. Hydrostatic test is widely used as a quality control method, but its parameters are often based on experience, with limited understanding of its effectiveness in detecting specific defects. This study quantitatively evaluates the sensitivity of hydrostatic test to typical defect types in large-tonnage porcelain insulators. Finite element simulations were conducted to analyze how defect size, shape, and material properties influence stress distribution. The results provide insights into the defect elimination mechanisms of hydrostatic test and support the development of the more standardized and effective testing procedures.