The outdoor insulation of the transmission lines of Hunan Power Grid is checked in this paper

the result displays that there are 66. 05% of 220kV transmission lines can not meet the demand of prevent ice-melting flashover

and for 500kV transmission lines

the percentage is 36. 17%. And in the superposition region of heavy icing area and e class pollution area

there are 1. 03% of towers can not meet the demand of prevent ice-melting flashover for 220kV transmission lines

and for 500kV transmission lines

the percentage is 0. 45%. Self-defect and insufficient of anti-icing improvement are the primary causes of the poor prevent ice-melting flashover capacity for the overhead transmission lines. The strategy of prevent ice-melting flashover by improving forecast accuracy ment

reinforcing the manager of ice condition observation

classifying and focusing on the poor prevent ice-melting flashover capacity facility are proposed. And the operation and improvement advice for prevent ice-melting flashover is also proposed in the paper.