What is online monitoring of transformer oil spectroscopy? Photoacoustic Spectroscopy Technology Principle Explained

• Principles of Photoacoustic Spectroscopy: When a specific wavelength of modulated light irradiates a gas molecule, the gas molecule absorbs the light energy and then releases heat through a radiationless leap, causing the micro-region gas to expand to produce acoustic waves. The intensity of the acoustic signal is proportional to the gas concentration. By switching different wavelength filters, the concentration of each gas is detected one by one.
• Differences with chromatographyChromatography requires physical separation of gas mixtures in a column before detection, while photoacoustic spectroscopy uses spectral features to identify gases directly, eliminating the need for a column and carrier gas system.
• Core AdvantagesNo carrier gas, no column, low maintenance, fast detection speed, especially suitable for unattended sites with limited maintenance conditions.

1. In-depth technical rationale

The physical basis of photoacoustic spectroscopy is the photoacoustic effect. Gas molecules have characteristic absorption spectra - each gas has a unique absorption peak at a specific wavelength. The system selects different wavelengths to irradiate the gas to be detected by switching the narrow band filter. If the wavelength of light is absorbed, the gas molecules are excited to release heat through intermolecular collisions, which generates a periodic pressure wave (sound wave) under the frequency of the modulated light, which is detected by the high sensitivity microphone.

This "spectral identification" approach avoids the need to physically separate the gases before detection in chromatography and simplifies the system structure considerably - eliminating the need for a column thermostat, carrier gas cylinders, and a complex gas line system.

2. Strengths and scenarios

2.1 Maintenance-free operation--Not dependent on carrier gas and columns, minimizing the need for on-site consumable replacement. This is especially advantageous for remote substations, high altitude areas, or sites with limited transportation.

2.2 Rapid detection-Eliminates the need for chromatographic separations and provides faster detection in a single run. Provides more timely failure warnings in emergency scenarios that require quick judgment.

2.3 Compactness-Without gas line system and column thermostat, the size and weight of the equipment can be made smaller.

3. Frequently Asked Questions FAQ

3.1 Q. How many gases can be detected by photoacoustic spectroscopy?

A: Depends on the number of filters configured in the system. Mainstream products can cover 3~7 kinds of malfunction characteristic gases, and some models can detect less varieties than high-end gas chromatography systems.

3.2 Q. Is spectroscopy completely maintenance-free?

A: No need for carrier gas and column replacement is its biggest maintenance advantage, but the light source has a service life, filters need to be kept clean, and the oil circuit part still needs to be checked regularly.

3.3 Q. Can data from spectroscopy and chromatography be directly compared?

A: The two detection principles are different, the absolute value may have deviation. When doing trend analysis, the same equipment should be kept for continuous monitoring, and the detection method should not be changed frequently to ensure the consistency of the data.

Disclaimer: The content of this article is for technical exchanges and reference only, and does not constitute any form of procurement commitment or contract offer. Product technical parameters, configuration programs and prices are subject to the actual signed contracts and technical agreements.

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