Corrosion of Epoxy-Sealed Aluminum Tail-pipe of High-Voltage Cable Terminal

The corrosion defect of some epoxy-sealed aluminum tail-pipes of high-voltage cable terminal in Shanghai was analyzed from several aspect, including investigation of rainwater composition in Shanghai area, chemical composition and corrosion resistance analysis of aluminum sheath and aluminum tail-pipe, solidification conditions, compatibility and sealing performance of epoxy paste, terminal leakage current. The main causes of the corrosion of the terminal tail-pipe were summarized. The results showed that the poor epoxy-sealing caused acid moisture or water to invade and remain on the surfaces of aluminum tail-pipe and sheath for a long time. In addition, the leakage current through copper braid generated induced voltage. Under the combined action of water and electric field, the passivation protective film on aluminum surface was damaged, finally leading to corrosion of aluminum tail-pipe and other structures.