Typical Fault Case Analysis of SF6 Densimeter

Sulfur hexafluoride (SF6) is widely used in modern power equipment due to its excellent insulating and electrical properties. Accurate measurement of its gas density is crucial for the reliable operation of the equipment. However, SF6 density meters may experience various malfunctions, leading to false alarms or delayed alarms. Therefore, it is necessary to analyze SF6 meter malfunctions, identify the causes, and develop countermeasures. Regarding the malfunction where the electrical contact resistance is approximately infinite during the calibration process of the density meter, this paper first conducted an on-site investigation and performed real-loop simulations on the faulty density meter samples, as well as electrical contact performance checks. Finally, through characterization and analysis of the terminal samples, it was concluded that the cause of the approximately infinite electrical contact resistance was electrical corrosion of the terminals, which subsequently led to excessive resistance and contact failure in the relay during calibration. The research conclusion indicates that electrical corrosion is a key factor leading to SF6 density meter malfunctions. It is recommended to optimize equipment design (enhancing sealing performance) and improve operation and maintenance strategies (high-frequency inspections and digital transformation) to systematically enhance equipment reliability and prevent potential risks.