Why Are Wedge-shaped Tension Clamps Easily Misdiagnosed As Flashovers At High Altitudes?

As altitude increases, atmospheric pressure decreases, significantly reducing the insulating strength of the air medium. In areas above 2000 meters, electrical clearances require correction, with the correction factor increasing with altitude. The clamp dead end insulation core, made of engineering plastic, has a withstand voltage rating and operational voltage margin designed for conventional sea level that are difficult to maintain under thin atmospheric conditions. This change in physical conditions may superficially appear as abnormal line operation, but it stems from a reduction in air breakdown voltage.

Flashover in overhead lines is caused by a combination of factors. In high-altitude areas, parameters such as the phase-to-phase distance of insulator strings, the electrical clearance between conductors and grounding bodies, and the spacing of insulating elements inside the dead and clamp insulator face more severe challenges due to the reduced air density. Workers often attribute problems to conductor displacement, flashover, or other external factors based on fault recording data and on-site investigation conclusions, neglecting the natural attenuation of material insulation properties under specific altitude conditions. In particular, the wedge core of the dead clamp uses insulating material, and the critical value of surface discharge and volume breakdown is significantly reduced at high altitudes. This makes it easy for micro-breakdown to occur at stress concentration points, eventually evolving into a detectable flashover event.