Breakdown modeling of HVAC-GIL tri-post insulator subjected to electric field and mechanical loading

Abstract

This research develops a simulation model, aiming to study the breakdown process of the tri-post insulator when exposed to electric field and mechanical loadings. The insulator is subjected to external forces of varying magnitudes and directions, along with an applied 1100 kV AC voltage. Results show that the breakdown process is driven by the electrostatic energy density (Wele) under an AC voltage. As the length of the breakdown channel increases, Wele, also rises, thereby accelerating the extension of the breakdown channel. After applying a straight tension along the insulator post, the tensile stress and the corresponding strain energy density become concentrated near the tips of the lateral branches, thus promoting their expansion and even causing a transverse fracture under the condition of 100 kN. In the case of a small straight compression below 25 kN, the breakdown process can be restrained. But when it comes to 75 kN, the breakdown process is promoted again, and a shear fracture can be caused above 100 kN. Under diagonal tensile or compressive stress, the breakdown channel deviates towards the applied force due to asymmetric strain energy density distribution. The objective of this research is to improve the comprehension and forecasting of breakdown in dielectric materials.

Keywords

• Modeling
• breakdown
• insulator
• electrical
• mechanical
• HVAC-GIL