Analyzing influences of snowfall on electric field at the interface of composite cross-arm with finite element method

Abstract

The composite cross-arm was used in large numbers in power systems due to its safety and economic advantages. The interfaces were the weak link in the property of composite cross-arm. However, the influence of severe weather such as ice and snow on the interface property was not clear, which would bring potential risks to operation safety for composite cross-arm. To this end, the finite element method was used to study the characteristics of the electric field at the FRP-silicone rubber and FRP-RPUF interfaces under snowfall conditions in this paper. Firstly, the snow and snowmelt models of the composite cross-arm were established by combining the natural snowfall conditions and the classical snowed model, then the influence of snowed degrees, snowmelt stages and dry-band on the interfaces electric field was analyzed. The results show that the snow without melting basically does not change the interface electric field. During the snowmelt stages, the average electric field intensity of the FRP-silicone rubber interface increases and the maximum electric field intensity of the two interfaces decreases. The distortion of the interface electric field caused by the dry-band in the middle snowmelt stage is the most serious, at this time, the electric fields at FRP-silicone rubber interfaces reach a maximum of 14.72 kV/cm and 8.53 kV/cm respectively. When the length of dry-band reaches or exceeds the distance between the high-voltage fitting and the eighth large umbrella skirt, it basically no longer causes the distortion of interface electric field. Compared to the FRP-RPUF interface, the FRP-silicone rubber interface is more severely affected by snowfall. The results can provide a reference for improving the interface property and ensuring the safety of the composite cross-arm in severe weather conditions.