Ultrasonic sensor used for detecting transformer partial discharge signal

Abstract

The invention discloses an ultrasonic sensor used for detecting a transformer partial discharge signal, which can prevent a non-receiving face signal from being introduced and has strong anti-electromagnetic interference performance and high precision. The ultrasonic sensor comprises a metal shell (1), wherein the front end of the metal shell (1) is fixed with a piezoelectric vibrator (2); a protective film (3) is arranged on the front face of the piezoelectric vibrator (2); and the piezoelectric vibrator (2) is connected with an output connector (5) through a signal processing circuit (4). The ultrasonic sensor is characterized in that the piezoelectric vibrator (2) is an axial polarized piezoelectric vibrator, and the two axial ends thereof are plated with metal electrodes (6); the protective film (3) is a ceramic protective film, and the inner surface and the side face of the protective film (3) are plated with metal layers (7); and the metal layer (7) on the inner surface is connected with the metal electrode (6) on the front face of the piezoelectric vibrator (2), and the metal layer (7) on the side face is connected with the metal shell (1).

Description

Technical field: [0001] The invention relates to an ultrasonic sensor, in particular to an ultrasonic sensor for detecting the partial discharge signal of a transformer, which can avoid non-receiving surface signal input, has strong anti-electromagnetic interference performance and high precision. Background technique: [0002] As the voltage level increases, the internal insulation of the transformer bears a high electric field strength value, and partial discharge is easily generated at the weak insulation. Although this kind of discharge only exists in the partial position of the insulation, it will not immediately form the entire insulation penetration breakdown or flashover, but it is also very harmful: First, the insulating material adjacent to the partial discharge is directly impacted by the discharge particle. The bombardment causes local damage, and the second is that the heat, ozone, nitrogen oxide and other active gases generated by the discharge cause corrosion ...

AI Technical Summary

Problems solved by technology

At present, there are two types of protective films: ceramic and metal. Although the ceramic film protects the piezoelectric vibrator, it is easily interfered by external electromagnetic signals; although the metal protective film has good anti-electromagnetic interference performance, it is easy to be detected. The conductive connection of the metal part of the test object, the interference of the ground loop or the test object itself will affect the detection performance of the sensor

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