Identification of Hoarfrost Corona Losses Events Based on Advanced Operational Data Analysis and Weather Modelling

Corona losses on overhead line conductors due to hoarfrost lead to the highest corona losses in comparison to other weather conditions initiating corona (e.g. rain or wet snow). In this paper a promising methodology for identification and calculation of corona losses induced by hoarfrost using operational measurements, as well as a numerical weather model to predict hoarfrost on overhead transmission lines, is proposed. The methodology comprises the practical simplified procedure including operational measurements of the total line losses, subtraction of resistive losses, evaluation and subtracting of a measuring error from operational data. The results are further verified by application of advanced modelling using atmospheric data from a numerical weather prediction model and tested for actual overhead lines. The proposed hoarfrost model confirms its feasibility in identifying of observed corona loss events due to hoarfrost.