A novel protection method for icing lines of ring network

Serious ice covering on transmission line will make the line overload. As a result, it may cause many problems to equipments of the power system, such as power towers falling down, lines broken, icing flashover, network disconnecting and so on. With the development of power grid, there are more and more ring networks in the grid. Considering the unique structure of this network, this paper proposes a novel protection method for the icing line by choosing an optimal breaking point and gives an optimal mathematical model. The method could obtain a larger current for the icing line by disconnecting an optimal line and redistributing the power flow. If the obtained current is larger than the critical icing current, the ice covering on the line may stop growing and the line would be protected. Additionally, the ice could melt as the current is large enough. Finally, the simulation analysis by PSASP shows that this method is feasible and correct.