Unbalanced Tensions and Vertical Space Calculation of Tranmission Lines under Non-uniform Ice-coating and Ice-Shedding

The non-uniform thickness of ice coating and asynchronous ice shedding on overhead transmission lines in continuous spans cause changes of tension forces and collapse of tranmission towers. Unbanlanced tension forces are calculated using methods based ongraphic charts and matlab programming. The results show that unbalanced tensions are affected by non-uniform ice coating ratios, ice positions and conductor properties etc. With the suppressor of Hydro-Quebec, the bound height of transmission lines which endanger vertical spaces are analyzed under the drastic ice shedding. Anti-icing designers and de-icing workers should attach much more importances on the factors influencing unbanlanced tensions and on the calculation of vertical spaces.