Optical fiber photoacoustic sensing system and method for detecting dissolved gas in oil

Abstract

The invention discloses an optical fiber opto-acoustic sensing system for detecting dissolved gas in oil, which comprises a laser light source, a sensing channel, a detection light source, an optical fiber coupler, a reference channel, a high-speed spectrograph and a signal collecting and processing module. A sensing optical fiber is arranged on the sensing channel, a hole is formed in the side surface of the sensing optical fiber, and the sensing optical fiber is immersed in transformer oil. Laser emitted by the laser light source enters the sensing optical fiber of the sensing channel. The signal collecting and processing module collects spectral signals of the high-speed spectrograph, calculates the optical path difference between a reference channel and the sensing channel, obtains the amplitude of photoacoustic signals in the sensing optical fiber according to the change of the optical path difference, and obtains the concentration of dissolved gas in oil according to the corresponding relation between the amplitude of the photoacoustic signals and the concentration of dissolved gas in oil. The system has the advantages that the anti-interference performance is good, the dissolved gas in oil can be directly measured, and the adopted sensing optical fiber can be arranged in insulation equipment such as a transformer.

Description

technical field [0001] The invention relates to the technical field of on-line monitoring of high-voltage electrical equipment, and more particularly relates to an optical fiber photoacoustic sensing system and method for detecting dissolved gas in oil. Background technique [0002] During the operation of oil-immersed power transformers, faults such as overheating or discharge cause the insulating oil molecules to crack to produce small molecular characteristic gases, such as methane, ethane, ethylene and acetylene. Gas chromatography and photoacoustic spectroscopy are usually used in the analysis of these fault characteristic gases. Among them, photoacoustic spectroscopy is gradually replacing gas chromatography because of its high sensitivity and maintenance-free characteristics. [0003] In 2003, the British Kelman Company took the lead in developing the photoacoustic spectrum analysis equipment for dissolved gas in oil based on blackbody radiation infrared broad-spectr...

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Problems solved by technology

[0004] The technical problem to be solved by the present invention lies in the problem that the optical fiber photoacoustic sensor in the prior art has poor anti-interference performance, cannot directly measure the dissolved gas of oil and gas, and the metal sensor used cannot be placed inside insulating equipment such as transformers.

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