In this paper

a field application case of the acoustic-electrical combination method in partial discharge（PD）detection and localization of No.1 transformer in a 110 kV substation in Chengdu is introduced. For the abnor-mal discharge signal found in the acceptance test

a rough location is first performed using the detection impedancemethod to determine the approximate range of the discharge source. Secondly

based on the different propagationcharacteristics of acoustic-electrical signals of PD

and combined with ultrasonic testing technology

an acoustic-electric combination method is used to perform secondary accurate localization of the discharge source. Finally

therepetitive measurement of the PD signal after the defect processing and finite element method are performed to verify the accuracy and effectiveness of the acoustic-electrical combination method in the PD location of the transformer.