Non-contact type fiber ultrasonic sensor

Abstract

The invention provides a non-contact type fiber ultrasonic sensor. The side wall height central plane of a fiber installation ring is provided at its left side with a fiber fixing tube in the radial direction. The fiber fixing tube is provided therein with a single-mode fiber and a fiber collimating mirror superposing the central line. The right end of the single-mode fiber is mounted at the left end face of the fiber collimating mirror; the inner side wall height central plane is provided at its right side with a reflection mirror. The reflection mirror forms an angle of 45 degrees with the horizontally incoming laser beams; the lower end of the fiber installation ring is provided with a hollow plug; and the upper end of the hollow plug inside the fiber installation ring is provided with a sensing diaphragm. According to the testing, the non-contact type fiber ultrasonic sensor of the invention responds well, stably and sensitively to the ultrasonic signals in 300KHz wave band. In a real-time acquisition mode, the spectral signal to noise ratio is high, making it suitable to detect the ultrasonic waves generated by partial discharge of a transformer and to acquire ultrasonic waves in real time.

Description

technical field [0001] The invention belongs to the technical field of sensors, and in particular relates to ultrasonic sensors. Background technique [0002] The power transformer is an important electrical equipment in the power system. It is in a pivotal position in the power system. Once a fault occurs, a large-scale power outage may occur, which will bring great losses to the power system and the national economy. Therefore, the power system attaches great importance to the power transformer. state, especially the health of its insulating media. Since the insulation structure of power transformers usually adopts oil-immersed composite insulation with good insulation performance, with the development of power systems and the increase of voltage levels, partial discharge has become an important cause of insulation degradation of power transformers, so the detection and evaluation of partial discharges is also important. It has become an important means of monitoring its ...

AI Technical Summary

Problems solved by technology

Although the electric pulse method is the basis of partial discharge research, the electric pulse signal will have a lot of interference (usually above several thousand PCs) when it is detected in the field, and it is difficult to obtain the discharge signal correctly. In addition, the problem of online calibration and online results Equivalence with offline results and other issues have long plagued the online detection of transformer partial discharge by electric pulse method. At present, in the field, engineers and technicians often pay more attention to the detection of partial discharge of operating transformers, especially when the discharge capacity is large. , by detecting partial discharge to determine the degree of damage to the transformer insulation

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