The discharge characteristics of typical partial discharge source were analyzed for commercial switchgear. Transient Earth Voltage（TEV）and ultrasonic Partial Discharge（PD）detection technology were used to detect and analysis on the typical partial discharge source

and integrated compliance tested effectiveness of（TEV） and ultrasonic PD detection technology. Experimental results showed that different typical defects of discharge pulse have different phase distribution characteristics. The same typical defects of discharge pulse have different phase distribution characteristics with the different discharge energy. Ultrasonic detected signal spectrum was mainly concentrated in the fundamental and harmonic

components of 40 kHz due to the sensor frequency range

and the discharge more intense

the more harmonic component frequency. For insulation cavity discharge

the effectiveness of ultrasonic detection was poor. Ultrasonic detected signal spectrum was mainly concentrated between 3

8

0 MHz

high frequency component was less（above 150 MHz）. The spectrum of TEV detection partial discharge sources were different

and there were a large number of spectrum component in suspended electrode defect.