 This study investigated the charge transfer properties at oil solid interfaces using an oil droplet triboelectric nanogenerator oil droplet ton. It was found that the electron species dominate the initial stage of the triboelectric charging process. Additionally, the charge transfer mechanism in multi-component liquid mixtures during the electric double layer EDL development process was proposed to explain the component competition effect. Furthermore, a tubular tongue was developed as a self-powered sensor for transformer oil trace water detection. The device demonstrated high water sensitivity with a detection limit of 10 muL slash L and a response range of 10 to 100 muL slash L. This research revealed the oil solid triboelectric and charge transfer competition mechanism in EDL, opening up a new channel for real-time online monitoring of trace water and transformer oil, which holds promise for information perception and intelligent operation of transformers in the power industry. This article was authored by Song Xiao, Hao Ying Wu, Nan Li, and others. We are article.tv, links in the description below.