变压器局部放电监测用压电传感器的压电材料特性及器件尺寸对灵敏度的影响研究

Aiming at the contact piezoelectric ultrasonic sensor with the core sensing element of piezoelectric ceramic cylinder，the influence of piezoelectric material properties and size of element on the sensitivity of acoustoelectric conversion is studied. Based on physical field finite element simulation，the model of piezoelectric ultrasonic sensor is set up.Then，influence of the piezoelectric material characteristic parameters and the sensor structure parameters on the sensor acoustoelectric conversion sensitivity and resonant frequency in the frequency range of partial discharge of transformer is analyzed. And the design method to improve acoustoelectric conversion sensitivity of the sensor is proposed.The simulation results show that within the frequency range of 20-250 kHz，the sensitivity is maximum with selection of piezoelectric material of PZT-2，diameter of 6 mm and thickness of 12 mm.When selecting the piezoelectric material of the sensor，the piezoelectric material with large constant d₃₃ shall be selected firstly，and short circuit elastic compliance constant s^E₁₃ and s^E₁₃ of the material are modified through performance improvement so to achieve adjustment of the resonant frequency of the sensor.Finally，the simulation results of the structure optimization are verified by experiments，and the experimental results and the simulation results are in agreement.