Effect of droplet deformation on discharge at icicle tip of ice-covered insulators during melting period

Abstract

• The drop of melting water affects the gap discharge of ice-covered insulator. • The electric field of the gap varies with the deformation of the water droplets. • The effect of droplet deformation on gap discharge is related to icicle length. Existing studies show that icicle tip discharge of insulators is related to overhanging melting water droplets. However, the effect of dynamic deformation of droplets on the icicle tip discharge has not been studied. In this paper, the experiments of dynamic deformation of melting water droplets and discharge during melting period of composite insulators with a spacing of 70mm for big umbrella skirts are carried out. Furthermore, a fluid-electric field coupling simulation model under different icicle lengths corresponding to the experiment was established . The results show that the dynamic deformation of the melting water droplet increases the intensity of the air gap electric field and affects the discharge at the air gap. When the icicle length is 50 mm, the electric field intensity of the gap during the droplet breaking increases by more than 170%, and the air gap discharges at this time. When the icicle length increases to 60 mm, the length of the air gap decreases with the droplet deformation, and discharge occurs before the droplet is broken. When the icicle is almost bridged, the discharge phenomenon will be observed all the time at the air gap.