Modeling of AC arc inside wet snow

Overhead transmission lines traverse long distances and generally pass over a variety of regions with different kinds of relief (earth topography, altitude, etc), climate (temperature, pressure, wind, etc), and environment (industrial parks, coastal areas, etc). In this regard, high voltage outdoor equipment is subjected to various forms of constraint. Among those, pollution, wet snow and atmospheric icing of outdoor insulators are recognized as being the major factors at the origin of power outages recorded on the transmission lines, and appear to be factors of very high importance in the quality and the reliability of energy distribution. Indeed, outdoor insulators can be covered with dust (slightly conducting but hygroscopic), with atmospheric ice or melting snow. Electric arcs can be initiated under certain conditions, and develop until they cause the total flashover of the insulator. Thus, within the framework of the activities aiming at increasing our basic knowledge of the initiation of electric discharges inside snow and their development into flashover, the Industrial Chair CRSNG/Hydro-Quebec/UQAC on atmospheric icing of power network equipment (CIGELE) undertook a vast research program based on the study and the modeling of the flashover of snow-covered insulators. The main objective of this PhD project consists of establishing a mathematical model able to predict the flashover voltage of snow-covered insulator surfaces. An important project for the adequate design of the insulators intended for cold regions. The comparison of the results obtained by the mathematical model with those obtained in experiments shows a very good agreement.