Analysis of Failure Causes for O-Ring Seals in the Converter Station and Study of Countermeasures

O-ring seals are particularly popular due to their small size, ease of installation, good sealing performance, and ability to provide bi-directional sealing with a single piece, they are widely used in converter station equipment. They are commonly used for sealing oil, water, and gas circuits in equipment such as transformers, valves, and GIS. The failure of the O-ring may cause SF6 gas leakage, damp in the circuit of the measuring device, leakage of the cooling medium, and insulation failure caused by the failure of the rubber ring into the equipment, it has become an important factor affecting the safe and stable operation of converter station equipment. The article introduces the common sealing structure and sealing principle of O-ring seals, and analyzes the causes of O-ring seal failure based on three cases of failure in UHV converter stations. Finally, several suggestions for preventing failure are put forward from the selection of seal ring material, assembly process, storage of spare parts and so on.