Photoacoustic detection of dissolved gases in transformer oil

Abstract

SUMMARYThis paper investigates the applications of photoacoustic spectrometry (PAS) to analyze dissolved gases in transformer oil. An inexpensive experimental device with an electric pulse infrared light and six filters has been developed to detect six main fault gases in transformer oil, namely, CH 4 , C 2 H 6 , C 2 H 4 , C 2 H 2 , CO, and CO 2 . The method of choosing the characteristic wavelengths for the above six fault gases is discussed in detail. A weighted least-square error method is proposed to analyze the measured data and to determine the component concentrations of dissolved gas in oil. Two sample sets of gas mixtures are analyzed by the experimental device for the purpose of verification. The PAS measurements are compared with the true values and the values measured by a conventional gas chromatograph (GC) method. The comparison results show that PAS is an effective way of analyzing dissolved gases in transformer oil, which exhibits some advantages in the gas detection such as consuming no gas, separating no gas, high accuracy, high stability, and rapid measurements.

Detection of Dissolved Carbon Monoxide in Transformer Oil Using 1.567 μm Diode Laser-Based Photoacoustic Spectroscopy

“…Photoacoustic spectrometry is a kind of calorimetric spectroscopy technique with high sensitive and dynamic range based on the gas photoacoustic effect [6]. The basic principle of gas photoacoustic effect is represented in Figure 1.…”

“…Gas detection with the PAS system mainly depends on the wavelength of the radiation light source; thus the radiation wavelength of the DFB diode laser should be well-matched with the characteristic spectrum line of the target gas [6]. The basic principles [14] for choosing the characteristic wavelengths of CO gas are as follows.…”

“…On the basis of the fluid mechanism and thermodynamics law, the gas PA signal PA can be expressed as follows [6,15]:…”

“…And it has been widely used in assessing the insulation state of running transformers. Online monitoring and analyzing the gas concentration and generation rate of dissolved CO gas in transformer oil plays a quite significant role in transformer condition assessment and fault diagnosis [6]. In recent years, interest in CO gas detection has been extremely simulated and many researchers have been immersed into this field [5][6][7][8][9].…”

“…Online monitoring and analyzing the gas concentration and generation rate of dissolved CO gas in transformer oil plays a quite significant role in transformer condition assessment and fault diagnosis [6]. In recent years, interest in CO gas detection has been extremely simulated and many researchers have been immersed into this field [5][6][7][8][9]. And metal oxide semiconductors, palladium gate field effect transistors, catalytic combustion sensors, and fuel cell sensors are the main conventional methods used to detect and analyze dissolved gases in transformer oil [5,7].…”