Development of an Online Detection Setup for Dissolved Gas in Transformer Insulating Oil

Abstract

The type and concentration of dissolved gases in transformer insulating oil are used to assess transformer conditions. In this paper, an online detection setup for measuring the concentration of multicomponent gases dissolved in transformer insulating oil is developed, which consists of an oil-gas separation system and an optical system for acquiring the transformer status in real time. The oil-gas separation system uses low pressure, constant temperature, and low-frequency stirring as working conditions for degassing large-volume oil samples based on modified headspace degassing. The optical system uses tunable diode laser absorption spectroscopy (TDLAS) to determine the gas concentration. Six target gases (methane, ethylene, ethane, acetylene, carbon monoxide, and carbon dioxide) were detected by three near-infrared lasers (1569, 1684, and 1532 nm). The stability of the optical system was improved by the common optical path formed by time-division multiplexing (TDM) technology. The calibration experiments show that the second harmonics and the concentrations of the six gases are linear. A comparison experiment with gas chromatography (GC) demonstrates that the error of acetylene reaches the nL/L level, while the other gases reach the μL/L level. The data conforms to the power industry testing standards, and the state of the transformer is analyzed by the detected six characteristic gases. The setup provides an effective basis for the online detection of dissolved gas in transformer insulating oil.

Experimental Research on Measuring the Concentration of CO2 in Gas-Liquid Solution Based on PZT Piezoelectric-Photoacoustic Spectroscopy

“…On the other hand, as is shown in Table 1, it is clear that the average value of the concentration of CO 2 in each solution was lower than that of the standard solution, which can be explained by the loss of CO 2 caused by the liquid pump at the very beginning of the experiment. Finally, figures in Table 1 demonstrate that the time of each measurement was less than 60 s, which saved at least 10 min compared with devices proposed in the literature [34,35].…”

Development of gas chromatography for dissolved gas in oil based on nitrogen plasma discharge detection principle

“…At present, in the national standard, the separation of oil and gas in transformer oil usually obtains the gas to be detected by incomplete separation combined with headspace gas extraction and oscillation separation [8,9]. For the detection of lower hydrocarbons, such as methane, ethylene, ethane, acetylene, etc., the hydrogen flame ionization detector is usually used for detection; for hydrogen, the thermal conductivity detector is used for detection; for oxides such as carbon monoxide and carbon dioxide, it is necessary to first convert them into flammable gases (converted by a Ni converter), and then use a hydrogen flame ionization detector for detection [10].…”

Rapid detection of dissolved acetylene in oil based on T‐type photoacoustic cell

“…The measurement accuracy of dissolved C 2 H 2 in oil reached 1 μL/L. 22 Whereas, gas chambers with large size and long optical paths need massive oil samples to ensure sufficient degassing.…”

“…In 2021, Chen et al developed a TDLAS‐based analytical instrument for dissolved gases in oil. The measurement accuracy of dissolved C 2 H 2 in oil reached 1 μL/L 22 . Whereas, gas chambers with large size and long optical paths need massive oil samples to ensure sufficient degassing.…”