Switchgear partial discharge is an important factor which causes switchgear insulation aging that leads to power accident. Combined with lumbar station substation project

3 ultrasonic sensors are mounted on the joint of 35kV switchgear and cable channel

and switchgear partial discharge is on-line detected. The partial discharge phenomenon occurs with the process of sound physical transformation

according to quantitative and qualitative relations of ultrasonic wave characteristics and partial discharge

insulation condition of switchgear will be detected and diagnosed. Monitoring data show that ultrasonic wave sensor numerical range is 204

422mV. In a certain extent

data curves reflects change of switchgear partial discharge

and provi

des effective support for further power fault forecasting.