The existing on-line monitoring system for switchgear is inefficient in economy

complex in installation

and insufficient in channels. To address these issues

this study developed a portable on-line partial discharge moni-toring system for switchgear. The system is based on TEV

and has a distributed architecture with multiple front endsand one terminal. The wireless communication based on Zig Bee was employed to expand the number of front endsand the detection range

and improve system reliability and economy. This paper introduces the architecture andmain design parameters of the on-line monitoring system

as well as the software’s functions and operation interfac-es. This monitoring system has been applied to some transformer substations

and a partial discharge defect was dis-covered in a 35 kV switchgear. It is concluded that the system is stable and reliable

and can satisfy the requirementfor on-line partial discharge monitoring of switchgear.