Observational validation of a numerical model to simulate snow accretion on a transmission line conductor with moment of inertia and torsion compliance

We have developed the SNOVAL computational code to numerically simulate snow accretion on the conductor wire of a transmission line. Here, we present the theoretical aspects of SNOVAL version 2 such as the derivations of the model equations based on the physical process of snow accretion and conductor wire torsion, and the derivations of the mathematical form of the spatial and temporal discretization of the model equations. The validity of SNOVAL is examined using observational data obtained using a sector model apparatus designed to mimic snow accretion and wire rotation at the center of an actual transmission line. Field observations indicate that the SNOVAL snow accretion model is appropriate, although the SNOVAL results depend strongly on certain computational conditions such as the sticking efficiency, the accreted snow density, and an assumed mass-weighted terminal fall speed of wet snowflakes. Finally, the applicability of SNOVAL to snow accretion on a transmission line is demonstrated via numerical simulation of the dynamic behavior of wire rotation such as the snap-through phenomenon of a conductor wire equipped with counterweights.