高灵敏度PMN-PT压电薄膜传感器的研制与发电机定子绕组局放监测OA

To monitor partial discharge ultrasonic signals near the stator winding slot of a generator and improve the in-sulation system state assessment capability,an implantable and highly sensitive PMN-PT piezoelectric thin-film sensor is developed for deployment at the end-winding slot.The effectiveness of this sensor is also validated.First,the PMN-PT thin film is fabricated using the sol-gel method,and the sensor performance is optimized through electrode structure de-sign and acoustic impedance matching materials.Second,the sensor's strong anti-interference capability,high sensitivity,and excellent frequency response characteristics are validated through needle-tip-pulse discharge experiment and acoustic emission lead-breakage experiment on the polyethylene plate.Finally,an artificial defect is created on the prototype stator winding bar to verify the effectiveness of PMN-PT piezoelectric thin-film sensor in discharge monitoring.The experi-mental results show that,for the partial discharge event with an apparent discharge of 3 746 pC,the designed PMN-PT sensor can detect a maximum output voltage of 0.4 V,its sensitivity is about 1.74 times higher than that of the traditional ceramic sensor,and the frequency response range is extended to 400 kHz.This study provides an innovative solution for the online monitoring technology of generators,which not only significantly improves the real-time monitoring capability of insulation status,but also lays the foundation for the safe operation of power equipment,demonstrating important ap-plication prospects.