In this paper

the detailed process

defect treatment

causes a

nalysis and subsequent rectification measures of partial discharge live detection abnormality of 1 000 kV GIS circuit breaker is introduced. Maintenance personnel analyzes abnormal signal characteristics of ultrasonic and UHF partial discharge by way of such works as partial discharge live detection and SF

6

decomposition detection for 1 000 kV GIS equipment

locks position of the abnormal signal and judges that the slight fault possibly exists inside the GIS. Then

the existence of the fault is confirmed by the inspection at site

the faulty circuit breaker is replaced and the faulty circuit breaker is stored as it is and returned to the manufacturer for analysis. Finally

the reason of abnormal partial discharge is found out by way of opening the enclosure at site

disassembly at factory and detection of foreign matters. The reason of abnormal partial discharge of the 1 000 kV GIS circuit breaker is due to shield breakage and the looseness of the tightening screws. The main reason for the shield breakage is due to the looseness of the tightening screw of shield

uneven stress of the shield which causing metal fatigue and breakage near the mounting hole of the shield. While the the reason of the looseness of the screw is caused by incorrect application of the locking agent and nonconformity of the tightening torque to the requirement. Later on

the same type of equipment is rectified

the structure of the shield at the stationary side is optimized

and the overall strength of the shield is increased. The semicircular washer at the bolt connection of the shield is added

and the tightening screw washer of the shield is replaced by the special washer with larger external diameter so to improve tightening reliability of the shield. Throughout treatment and analysis of the defect

the corresponding countermeasures in such aspects as GIS installation

acceptance

operation and maintenance is formulated so to prevent recurrence of such defects.