To understand the propagation characteristics of ultrasonic signal brought about by partial discharge inGIS

the finite element method is adopted to simulate the ultrasonic signal propagation characteristics of the partialdischarge in different locations of ultra-high voltage（UHV）GIS. A three-dimensional UHV GIS simulation model isestablished

and the monopole sound source is set at the surface o

f the GIS center conductor and the spacer respec-tively. Multiple ultrasonic sensors are arranged at different positions of the GIS enclosure to receive the ultrasonic sig-nal generated by partial discharge. The ultrasonic sound pressure distribution on GIS wall

which is generated by dif-ferent monopole sound sources

is obtained via simulation

and the characteristics of the ultrasonic signal in time-fre-quency domain are also obtained. The game process of different paths of the ultrasonic signal is discussed. By analyz-ing the time sequence of the received ultrasonic signals from different monopole sources

the ultrasonic signal trans-mission paths versus different source locations are determined. Simulation results show that: 1)when the monopolesound source is located in the center conductor remote from the spacer

the ultrasonic signal first reaches GIS enclosure with the shortest distance between the monopole sound source and GIS enclosure

then spreads to both sides;2)when the monopole sound source is located on the spacer or the center conductor near the spacer

the ultrasonicsignal spreads along the spacer to GIS enclosure and then spreads to both sides;3)the ultrasonic spectra received bythe sensors almost concentrates in the range of 30

4

0 k Hz

while the ultrasonic signals attenuate quickly in higherfrequency range of 60

8

0 k Hz;and 4)the attenuation process of the ultrasonic signals follows exponential functionwhen the sensor keeps away from the source

and the signals attenuate more seriously when they propagates acrossthe spacer.