Study on the Protective Effect of the Defective Insulating Sheath Used for Transmission Lines

In recent years, bird damage has occurred frequently. Among the current bird prevention measures, insulating sheaths have gradually been promoted due to their advantages of convenient installation and excellent protection effects. However, when the wire is covered with the insulating sheath, there may be defects such as weak bonding, air gaps between the wire and the sheath; also considering that the sheath is running outdoors for a long time, severe climate changes will cause the sheath to crack and harden, etc. However, in actual projects, there may be cases where maintenance is not timely or it is difficult to find small defects in the sheath. Therefore, it is necessary to study the protective effect of the defective insulating sheath used for transmission lines. In this paper, a rod-plate model and a model of wire-coated defective sheath are established. Through analysis of the gap breakdown experiment and the test data, it is concluded that the defective insulating test piece and the defective insulating sheath can play a certain protective effect under the condition of a small gap distance.