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In order to overcome the shortcomings of traditional methods for corrosive sulfur detection in transformer oil, Raman spectroscopy based detection is proposed in this paper. The widely concerned corrosive sulfur, Dibenzyl Disulfide (DBDS), was chosen as the characteristic molecule to be detected. A series of oil samples with different DBDS concentr...
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... They have been successfully applied in the detection of trace gases in various scenarios [12][13][14][15][16][17]. Furthermore, they have gradually been applied in the field of dissolved gas detection and have shown promising application prospects [18][19][20][21]. Raman spectroscopy technology determines the presence and concentration of gases by measuring the frequency shift of Raman scattered light after it interacts with gases in water. ...
A R T I C L E I N F O Keywords: Dissolved gases in seawater Dissolved carbon dioxide analysis Photoacoustic spectroscopy Trace gas sensor A B S T R A C T A miniature mid-infrared photoacoustic (PA) gas sensor with a chamber volume of approximately 73 μL for detection of dissolved gases in seawater was presented. This sensor offers several advantages: small size, high sensitivity, low cost, and low power consumption. The strong absorption band of carbon dioxide (CO 2) near 4.26 µm was targeted by utilizing a mid-infrared microelectromechanical system (MEMS) thermal light source and a narrow bandwidth optical filter. The thermal light source was electrically modulated, which simplified the sensor structure. Double-pass absorption was implemented to enhance the PA signal, which was detected by a small and low-cost MEMS electric microphone. The gas entered the sensor through a small hole in a diffusion manner without the need for valves or an air pump. This design feature contributes to a compact structure with dimensions of only 2.43 cm × 1.25 cm × 1.8 cm. The analysis results showed that the minimum detection limit (MDL) of CO 2 reached 0.72 ppm with an averaging time of 100 s. A polydimethylsiloxane (PDMS) membrane was used as the water-gas separation unit. The performance of the designed PA sensor for detecting dissolved gases in seawater has been verified. When the flow rate of the water pump was 600 mL/min, the time for water-gas equilibrium was only 3.5 min. This can be attributed to the small size of the gas chamber and the rapid water exchange.
... However, the generated gas from the passivation reaction tends to result in the erroneous detection of the DBDS content by the characterisations of gas in the oil (GC-MS) [8,11]. Recently, non-destructive testing (NDT) and other detection technologies were introduced to characterise the sulfur corrosion degree: high-performance liquid chromatography (HPLC) [12], X-ray fluorescence spectroscopy [13], the terahertz (THz) time-domain spectrum (TDS) [14], Raman spectroscopy [15] etc. Nevertheless, how to achieve a feasible real-time monitoring technique of sulfur corrosion progression in insulating oils still needs wide recognition [13]. ...
As a typical failure phenomenon in transformers, sulfur corrosion has garnered significant attention in the field of high‐voltage engineering. Grain boundary character distribution (GBCD) copper windings have been introduced to enhance sulfur corrosion resistance by slowing down intergranular corrosion. In this study, the sulfur corrosion behaviour and mechanisms of the GBCD copper windings under various temperatures were experimentally and theoretically studied. Results show that GBCD can enhance the corrosion resistance of copper in liquid environments. With the increase in temperatures, the insulating properties of oil and papers in traditional copper windings experience notable degradation, while GBCD copper windings show more stable insulating behaviours. In addition, modelling of grain boundary energy indicates that the grain boundary structure of GBCD copper windings has a lower average interface energy of 0.170 eV/Ų. Calculations of reaction thermodynamics show that GBCD copper windings possess a higher failure temperature (135.2°C) and inhibition degree (activation energy) of the sulfur corrosion (32,557.62 J/mol), revealing the stability and enhanced sulfur corrosion resistance at elevated temperatures.
... Raman spectroscopy, as a noninvasive, nonsample consuming, and nonsample pretreatment optical detection method, is more and more widely used in many fields. 13 It has an excellent linear relationship between the intensity of the spectrum and the content of the objects to be measured. This makes it a great advantage in the field of quantitative analysis of substances, but due to its low intensity and weak signal, the lower limit of detection is often unsatisfactory. ...
Oil-paper insulated equipment is integral in power conversion and supports low-loss electricity transport. As a characteristic byproduct of the oil-paper insulation system, the realization of efficient detection of furfural in oil is crucial to the safe operation of the power grid. We proposed a novel approach using dual-enhanced Raman spectroscopy for sensing trace liquid components. This method employs a centrifugal extractor to separate and enrich the targeted components, achieving selective enhancement. The optimal phase ratio was determined to be 30:1. A liquid-core fiber was used to optimize the laser transmission efficiency and Raman signal collection efficiency, resulting in a nonselective signal enhancement of 44.86. It also investigated the impact of intermolecular interactions on the shift of Raman spectra, identifying the reasons for the differences in Raman signals between pure furfural, furfural in oil, and furfural in water. A batch of samples with furfural dissolved in insulation oil was measured using this system and achieved a limit of detection of 0.091 mg/L. The stability of the dual-enhanced Raman platform was experimentally verified with a spectral intensity fluctuation of 0.68%. This method is fast, stable, adaptable, and suitable for the detection of a wide range of liquid ingredients.
... Toyama et al. [9] proposed a highly sensitive analytical method to detect DBDS and its by-products by measuring the chemical reaction rate. Various optical spectroscopy methods like X-ray fluorescence [10] and Raman spectroscopy [11] were used to detect corrosive sulfur in transformer oil. Cong et al. [12] considered DBDS, dodecyl mercaptan, and dibenzyl sulfide as corrosive sulfur species and developed a generic formula to quantitatively estimate the degree of sulfur contamination in transformer oil. ...
Dibenzyl disulfide (DBDS) is the most prevalent corrosive sulfur in transformer oil. It reacts with the transformer windings to produce copper sulfide (Cu2S) and gets deposited on the insulating paper’s surface, leading to interturn faults within the transformer windings. Hence, this article proposes a deep neural network (DNN) to predict the DBDS content in transformer oil. The parameters like interfacial tension (IFT), breakdown voltage (BDV), water content (WC), oxygen, neutralization number (NN), color, furan content, and specific gravity (SG) were used as features to train and test the DNN model. The performance of the regression model was evaluated using mean absolute error (MAE), root mean square error (RMSE), and coefficient of determination (
${R}^{{2}}{)}$
. Moreover, extensive analysis is carried out by varying feature combinations and test-train ratios to obtain the best prediction model. The values of DBDS predicted by DNN were further used to determine the corrosive sulfur concentration in transformer oil. The proposed method is validated on real-life transformer data obtained from the online dataset and on data obtained from the local power utilities. A comparative study showed better efficacy of the proposed DNN model than other prediction models for accurate DBDS prediction.
