A variety of online detection techniques are used to diagnose abnormal discharges in the gas chamber of a quick earthing switch in a 220 kV substation.Through technical means such as ultra-high frequency partial discharge detection

ultrasonic partial discharge detection

and acoustic imaging

the type of abnormal discharge in the quick earthing switch's gas chamber is determined to be suspension discharge.It is decided to deenergize and disassemble the faulty gas chamber in light of the detection of decomposition byproducts such as SO2 and H2S

as well as signs of overheating in the SF6 gas during sampling tests.Subsequently

an in-depth analysis and discussion of the causes of the abnormal discharge are conducted.The results indicate that the primary cause of the suspension discharge in the earthing switch is an excessive gap between the square joint of the transmission shaft and the transmission insulator's shaft hole within the gas chamber.Additionally

the absence of the equipotential bonding springs between the metal insert grooves at the connecting points prevents the formation of a stable equipotential field between them.