Bird-body short-circuit faults is a primary type of bird-related faults on overhead transmission lines of 110 kV and above

severely affecting line operational safety.To analyze the underlying mechanism

a "tower-insulator-conductor-bird body" simulation model was established based on a 110 kV line tower and actual field conditions.The electric field distributions on the insulator

grading ring

and bird body surface were simulated under different flight postures.The results indicate that when the bird’s feather tips contact the grading ring

different flight postures significantly influence the surface electric field of the insulator and grading ring.Specifically

the field strength on the grading ring surface exceeds the standard limit of 20 kV/cm

making it prone to corona discharge.When the angle between the bird body and the insulator is 90°(insulator-tower plane)and 30°(insulator-conductor plane)

the feather tip surface field strengths reach 93.46 kV/cm and 100.7 kV/cm

respectively

which are likely to trigger bird-body short-circuit faults.Based on these characteristics

protective measures to enhance the insulation strength between high- and low-voltage ends of insulators are proposed.