In the process of mechanical de-icing of overhead lines

excessive impact load may induce severe shock of the conductor and ground wire

and even lead to the collapse of the tower. To determine the reasonable range of de-icing impact load

the critical value of strain energy density factor Sc at the tip of the icing crack is given in this study

and the criterion of icing shedding is further proposed. The criterion stipulates that the impact load acceleration when the strain energy density factor of the iced conductor reaches the critical value Sc is the critical acceleration

and the strain energy density factor S reaches or exceeds the critical value Sc (the impact load acceleration reaches or exceeds the critical acceleration) to determine the ice shedding. To verify the validity of the criterion

an impact de-icing experiment and a finite element calculation of the conductor segment model were conducted. Based on the criterion

the critical acceleration of ice shedding was determined and compared with the experimental data. Furthermore

taking the de-icing experiment of the whole-span real line in Quebec as the object

the finite element model of the whole-span conductor de-icing is created

and the critical acceleration

de-icing rate

and other key parameters are calculated by using the criterion of ice shedding. It is found that the critical acceleration of 15 mm

20mm and 25 mm icing shedding is 1817m/s2

1207m/s2 and 849m/s2 (compared with the experiment

the maximum error is 4.94%). The deicing rate of the calculation model is 70.6% (compared with the experiment

the error is 0.96%).