At present

the methods for detecting partial discharge（PD）in switchgear include such as acoustic emission（AE）method

ultra high frequency（UHF）method

transient earth voltage（TEV）method and high-fre-quency current method. However

comparative analyses on their sensitivity and locating effect are not enough. In this study

a real switchgear was taken as the partial discharge test platform

and three kinds of insulation defect models were established. The switchgear was applied different voltages

and the discharge quantity of these defect models was measured by the above four different methods. Comparison among the measurements indicates that AE method is the best in sensitivity

TEV method obtains the largest amplitude of PD signal

and the four methods have varying degrees of locating effect on partial discharge. It is concluded that the union of AE and TEV methods can achieve the most effective measurement of partial discharge in the switchgear with high background noise.