The ground wire of a 800 kV DC transmission line broke due to heavy icing

which resulted in single pole blocking fault and a single pole operation state for a long time. Through the comprehensive analysis and calculation of the unbalanced ice covering tension of the ground wire

the dip angle of the ground wire

the ice breaking jump and other aspects by the electrical calculation software of the transmission line

it is concluded that the unbalanced ice covering tension of the ground wire and the slip of the ground wire after the damage of the suspension clamp are the main causes of the accident. According to the analysis of the accident

some suggestions are put forward to avoid similar accidents again

which also provides reference for the follow-up engineering design.