The Icing Mechanism On Insulators And A New De-icing Method

In recent years, the transmission lines were suffered from ice disaster all over the world. Compared with other natural disasters, long-term snow always brought more serious damages.In this paper, the causes of ice formation on power lines and insulators are studied. Some methods used to prevent icing on insulators are summarized. The construction of the climate room is described in detail.Ice coating is a complex process of the collision between overcooling water drops and insulators. Thus based on the thermal equation of ice covering, this paper had a research in the thermodynamics process of ice covering, analyzed the water loading of the air and the wind speed's impact on the ice coating process. In this paper, a combined method of silicone rubber with different volume resistivity was proposed for de-icing. The volume resistivity of RTV was adjusted by adding conductive fillers. The method was focused on the problem that if the insulators were coated merely by semiconducting silicone rubber, in the days without snow, the large leakage current will bring enormous energy loss and cause thermal ageing of coatings. With this method, the leakage current will be small in the normal operation days and increase rapidly in snowy days, the energy loss and thermal ageing will be both weakened. This kind of silicone coating is developed successfully based on the RTV silicone coating. The coating's characteristics of hydrophobicity and semiconductivity were tested by experiments. Experiments were carried out to validate the effectiveness of the semiconducting RTV coating in a climate-controlled chamber.In this paper, a finite element model of long porcelain insulator string was calculated to explain the mechanism of combined RTV, normal RTV and semiconducting silicone rubber on de-icing and electric field homogenization. The best thicknesses of coatings which should be painted were also discussed.