Numerical investigations of a new thermal de-icing method for overhead conductors based on high current impulses

The theoretical background of a thermal de-icing method for overhead bare conductors subjected to ice accumulation is presented. The proposed thermal method is based on Joule effect but uses current impulses superposed onto the AC nominal current of the conductor whose perimeter is half-covered by a semi-elliptic ice sleeve. The purpose is to study the influence of environmental parameters on the shedding time obtained. For theoretical investigations, a specific numerical model using finite elements, finite volumes and explicit finite differences was developed. Several numerical simulations were carried out in order to study the influence of characteristic environmental parameters such as air speed, air temperature and ice thickness on ice shedding time, number of required current impulses as well as temperature distribution along the ice/conductor composite. The results obtained showed that the use of current impulses allows the confinement of the Joule effect heat to the ice/conductor interface. By decreasing the current impulse duration or increasing the current impulse magnitude, a more efficient heat confinement can be obtained at the ice/conductor interface. Also, the results showed than this method is not sensitive to wind speed and that shedding time is decreased with thicker ice sleeves.