Enhancement by Spark Discharge in LIBS Detection of Copper Particle Contamination in Oil-Immersed Transformer
Zhe Ye, Wei Ke, Wanting Wang, Huan Yuan, Xiaonan Wang, Xiaohua Wang, Dingxin Liu, Aijun Yang, Mingzhe Rong
Abstract
The detection of copper particles in transformer oil based on laser-induced breakdown spectroscopy (LIBS) technology has been preliminarily studied, but its limit of detection (LOD) needs to be further strengthened. Therefore, spark-discharge assistant method was used to solve the problem, and its enhancement mechanism has been studied in the research. The study of the correlation between spark-discharge-assisted LIBS (SD-LIBS) spectral intensity and Cu concentration shows that spark discharge has a significant increase in plasma size and spectral intensity; for Cu atomic lines at 324.75 and 327.39 nm, the determination coefficient <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${R}^{{2}}$ </tex-math></inline-formula> between their internal standard correction intensity and Cu concentration is promoted to 0.996 and 0.997, respectively; spark-discharge assistant method improves the LOD of LIBS from 0.775 to 0.112 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{g}$ </tex-math></inline-formula> /g. Due to the great improvement in detection performance, the application prospect of LIBS as fine particles detection method in transformer oil has become practical.