Study On Propagation Characteristics Of Ultrasonic Generated By Partial Discharge In Cable Accessory

In the large-scale power equipment for the local discharge research has been widespread concern,how can the local discharge occurs when the signal timely and effective capture and accurate positioning,the prevention of major accidents have important significance.In this dissertation,we study the propagation law of partial discharge acoustic signals in cable terminals and connectors,and explore a new method of PD detection using cable method.According to the basic theory of sound wave conduction,the cable terminal and joint model are established by using the finite element method of sound field,and the coupling propagation law of the partial ultrasonic wave at different media and interface is simulated.The influence of running temperature on the acoustic wave propagation characteristics was analyzed,and the modulus of the dielectric material at different temperatures was measured by dynamic thermall analysis(DMA).The density of the solid materials at different temperatures was measured.The ultrasonic waves propagation attenuation changes.were calculated at different temperatures.The simulation results show that the attenuation of the ultrasonic wave along the solid medium propagates along the temperature of the solid medium,but the change of the temperature of the silicone rubber with temperature is lower than that of other materials.The amplitude of the acoustic wave is close to the temperature Attenuation is small.Based on the analysis of the stress distribution of the solid medium in different positions,a high sensitivity detection method is proposed to install the optical fiber method-Perot ultrasonic sensor at the cable terminal flange.In addition,according to the simulation analysis of the PDS at different locations near the silicone rubber,two kinds of optical fiber partial discharge sensor installation scheme are proposed for the copper slot and the external connector of the adjacent connector cable outside the connector metal compression tube.And the sensitivity of the sensor acoustic response of the optical fiber sensor is simulated and analyzed.