Investigation the Parameters of Non-Cylindrical Ice Load on Power Transmission Lines

Abstract

Ice load on transmission lines is a critical factor that affects their cost and operation. National standards specify how ice load is considered in the design of power lines and poles. These standards generally use empirical relations that assume that the ice load on each phase accumulates uniformly and cylindrically. However, field tests and fault records show that the actual ice load on conductors is often not cylindrical due to altitude, wind strength and direction, and terrain topography. This study firstly defines several parameters to describe asymmetrical ice load. This load can cause additional vertical force on the line, conductor swing angle deviation, and sag changes. Since empirical equations are only valid for cylindrical ice load, the cross-sectional shape of the conductor must be transferred to millimeter paper, and calculations performed using one of several numerical integral methods. The coefficients for asymmetric ice are calculated in kg⁄m (N⁄m) using an AutoCAD model in the numerical study.