Partial Discharge (PD) is one of the main causes of degradation in polymer insulation materials under high-voltage systems. To enhance the insulation resistance against PD, an impregnation process using Polydimethylsiloxane (PDMS) filled with nano-sized silicone dioxide (SiO₂) particles was conducted. This study aims to evaluate the effect of SiO₂ concentration variation on the viscosity of…