Principle of Piezoelectric Sensors

Principle of Piezoelectric Sensors

Piezoelectric sensor piezoelectric material as a sense of power equipment discharge important materials, widely used in electric power equipment vibration monitoring, temperature measurement, voltage sensing and other fields, the core of which is the mutual conversion of mechanical and electrical energy, piezoelectric material subject to mechanical vibration, piezoelectric sensors, acoustic wave conduction, and other mechanical external forces, such as lattice aberration caused by the polarization state of the changes in the output sensor electrical signals, or measurement of the electric field effect Or measure the electric field on the piezoelectric material and the resulting deformation to reflect the size of the electric field voltage.

Acoustic signals can well realize the coupling and mutual conversion with electrical signals. Piezoelectric sensors can be divided into piezoelectric sensors, acoustic surface wave sensors, electro-acoustic pulse sensors, pressure wave sensors and so on according to the acoustic wave excitation, propagation and coupling methods.

According to the different ways of sensor coupling, piezoelectric sensors can be divided into contact and non-contact, contact piezoelectric sensors are mainly used for transformers, composite appliances and other large-scale power equipment monitoring, non-contact piezoelectric sensors are mainly used for power cables, switchgear and other power equipment detection.

Defects such as internal bubbles, surface cracks, etc., due to limitations in the manufacturing process, installation errors, etc., which result in partial discharges, are mainly detected by piezoelectric sensors for partial discharges of power equipment in the transmission cycle of the power grid.

After the insulating portion of the power equipment is discharged internally, ultrasonic signals are generated accordingly, and the ultrasonic signals propagate along the insulating medium and the metal conductor to the casing, and then propagate through the medium to the outside, and the piezoelectric ultrasonic sensors shown can be combined with the ultrasonic signals generated by partial discharges to be collected by setting up in the casing and the vicinity of the equipment of the power equipment and judging the discharging condition of the power equipment.

In addition, for the accurate positioning of piezoelectric sensor partial discharge problem, developed a 1616 array device planar ultrasonic phased array piezoelectric sensor array, the sensor center frequency of 150kHz, the bandwidth reaches 100kHz, the results show that the sensor can be sensitive to receive and locate the ultrasonic signals generated by the transformer partial discharge, but in the specific application of ultrasonic propagation of reflection, refraction and other complex issues need to be further studied. , refraction and other complex problems need to be further studied.

Piezoelectric sensors are also widely used in the detection of internal defects in power equipment, the principle is to detect the propagation characteristics of ultrasonic guided waves in the specimen to achieve a variety of material specimens of macroscopic defects, organizational structure, mechanical properties changes in the detection and characteristics of the high sensitivity, attenuation is small, and positioning is feasible.

Through the above introduction, we know the principle of piezoelectric sensors, if you still want to know the content of the micro acceleration sensors, general acceleration sensors, you can pay attention to us.

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