Morphological characteristics of decay‑like core rods in composite insulators under multifactor effects

With the extensive application of composite insulators in power systems, decay-like fracture has become an urgent problem to be addressed. Based on statistical data of decay-like fracture incidents from the State Grid Corporation, this study analyzes the key factors contributing to the decay-like deterioration of composite insulators, designs a multi-factor aging experimental platform, and conducts multi-factor aging tests on composite insulators under combined conditions of electric field, alternating mechanical load, and humidity. Under environmental conditions of 70 °C, 80 %RH humidity, an applied voltage of 30 kV, a buckling compression of 20 mm, and a buckling frequency of 0.05 Hz, morphological analysis was performed on a core rod sample from a composite insulator subjected to 30,000 buckling cycles (equivalent to an aging duration of 166.67 h). The surface and cross-sectional morphological characteristics of the core rod indicate that mechanical loading is related to the progression of insulator deterioration. The experimental results correspond with the buckling simulation outcomes obtained from a simplified core rod model.