Anti-Icing Technology Of An Overhead Line Based On Critical Current

The wire icing should be actively prevented because of its serious potential hazard in safe and in stable operation of electric power system.Based on the discussion of factors influencing the icing of an overhead line, formulas involved the critical current anti-icing method are theoretically derived and the Euler algorithm applied to calculate the local collection efficiency is mainly researched. Comparisons of the local collection efficiency, the kinetic energy of impinging droplet, the aerodynamic heating energy and the critical current for different ambient conditions are obtained by numerical simulation. It is shown from results that the distribution of local collection efficiency on the windward of a wire varies with the varying angle between the direction of wind and the horizontal plane; its value increases with the rising free airspeed or the increasing droplet diameter, but slightly influenced by the varying moisture content; the kinetic energy of impinging droplet increases with the rising air velocity, furthermore, the larger the moisture content, the larger the kinetic energy; the aerodynamic heating energy increases quickly with the rising air velocity and increases slightly with the rising ambient temperature; the critical current of a wire gradually increases with the falling ambient temperature, the increasing external diameter of a wire or the increasing moisture content under a certain air velocity.Based on the principle of network reconfiguration, a mathematical model of distribution network reconfiguration for wire icing is established. Illustrated with IEEE 16 nodes and IEEE 33 nodes standard distribution systems, verifying calculations for the feasibility of anti-icing reconfiguration on distribution network with a quick branch-exchange algorithm are done. It is shown from results that the active power losses after reconfiguration are decreased by 7.7% and by 31.5% respectively and currents in wires being in danger of icing are larger than critical currents. It means that preventing local wires from icing can be realized simultaneously while the network losses are decreased. The assumption that preventing wires from icing with distribution network reconfiguration is feasible in theory and the theoretical reference is supplied to the experimental investigation and the project application of the critical current anti-icing method.