HV power line overvoltage protector - has annular gap of specified width between active elements and has porcelain insulator

摘要

The excess voltage protector for power lines transmitting e.g. 125 kV has a cylindrical porcelain tube (3) with insulating ribs (5) sloping downwards around the inside. At the top is a metal cap (7) with a boss (8) on top for the conductor wire (9) connecting it to the power line. At the bottom is a metal flange (6) in contact with earth. Inside the cylindrical interior (4) is a stack of active elements (11), and the annular space (12) between is filled with nitrogen. The surfaces of the upper ribs have a coating for protection from dirt. The distance (A) across the space (12) inside is between 0.04 and 0.05 cm/kV.